Re: Increasing Motor RPM via VFD
Woodworkers Tool Works in Melrose WI will sharpen birds mouth.? Call to verify as I've not had it done for several years.? Dave
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Brian,
My results were fine with 14mm in Cypress but I took small steps. If endmill won’t allow a bigger step (depth of cut per pass) then i have no interest unless it was cheaper and bits would last longer. I don’t know if end mills can be sharpened
but no luck finding anyone to sharpen birdsmouth.
The previous owner demo in hard maple was not good. I don’t plan to get carbide but wanted to compare apples to apples.?
20mm birdsmouth in HSS is still over $100.
Lastly, my perception is that i will get clean bottom holes with end mills. Not sure if that is true.
Imran
On Jan 30, 2021, at 11:41 AM, Brian Lamb <blamb11@...> wrote:
?Are your existing results bad? I doubt it. I wouldn’t spend the money on carbide for the occasional mortise… a 3/4” carbide extended length end mill will set you back north of $100 and carbide is pretty easy to snap off, especially on these
comparatively flexible and rickety machines we are talking about. It would be a different story on a 10,000lb machining center.
Your best bet for 3/4” mortises would be an extended length HSS or Cobalt end mill. 4 flute would be stiffer, but because of less room for chip evacuation, it will tend to burn more, so I’d probably try a 2 flute version… stiffness in wood isn’t
the big issue anyway.
I just want to try and see if better results can be had. Jonathan mentioned center cutting, 4 flute end mills. Does anyone have a recommendation for 3/4” end mill? Felder supplied birds mouth is 100mm long for 20mm.
Generic end mills may be more affordable as well. Felder 18mm HW is $150.
Imran?
On Jan 30, 2021, at 11:07 AM, Brian Lamb < blamb11@...> wrote:
?VFD rated motors can generally run up to 200hz, CNC router motors up to 400hz. Torque does drop dramatically over about 90hz.?
OK, I’ll probably start a war… but you don’t need huge rpm on router bits or on these mortisers. You can’t manually move the cutters at a rate that justifies all this rpm, all you will get is burning. Now, on a CNC router, different story, it
has the capability to move the cutters at 500-1000ipm and can make use of all that rpm. I have machined mortises on my old Deckel mill and routinely done them at 1200 rpm and they come out great.?
On Jan 30, 2021, at 7:54 AM, David Kumm < davekumm@...> wrote:
Given the FD is direct drive, I would think the speed is closer to 3400 in the 60 hz market.? Generally you can overspeed a 2 pole motor to about 90 hz assuming the motor is decent quality.? Downside is that torque will be reduced because you aren't maintaining
the volts/hz ratio.? The benefit and need for higher speed is really for small diameter bits so the reduction in torque might not be a big deal.? 5/8" bits are not a great choice for more speed and less torque.
4 pole or 6 pole motors are good for higher hz and vector duty motors are good for something like 5000-6000 rpm or up to 240 hz.? When you do that you usually oversize the motor to compensate for the loss of torque on the high end.? You also need to realize
you may have way more torque on the low end than what the machine is designed for so care must be taken.??
Thank?Brian for straightening me out on this years ago when we had a discussion here about Rong Fu mills.? Dave
After realizing that people have used end mills on their mortising attachment, I was curious if there is a way to increase the RPM of FD250. The bit on morticing attachment is likely running around 5000 RPM, whereas FD250 is around
3000 RPM.
This article says it can be done as long as motor does not exceed it’s FLA, is not electrically overloaded and operating with it’s mechanical design limits.
Anyone got an idea how much more speed might be possible?
Electrical parts can be measured but I have no clue on mechanical side of what margin might exist.
This may not result in anything meaningful but I like to learn. One thing leads to another ....
Imran
|
Re: Increasing Motor RPM via VFD
I use two flute upcut spiral solid carbide end mills in my Multirouter using a variable speed motor 8000-24000rpm. I'm guessing I run it in the 10-12000rpm ballpark. Most often using 1/2 or 3/8" diameters. No burning at all, even at 24,000. Jason Holtz
J. Holtz Furniture
3307 Snelling Ave. South
Minneapolis, MN 55406
612.432.2765 -- Jason J. Holtz Furniture 3307 Snelling Ave. South Minneapolis, MN 55406
|
Re: Increasing Motor RPM via VFD
Joe,
I had to use supplemental holding when I just had single eccentric clamp. When I made clamps for K975, I intentionally used vertical shaft design same as FD250 and bought two extra vertical shafts. This allows me to remove clamps off the vertical shaft of saw and place them on FD250. Have yet to use them and still need to figure out air connections.
Imran
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On Jan 30, 2021, at 12:55 PM, bacchus6015 via groups.io <joeinno@...> wrote: ? I did not find the speed with the FD250 at 60 Hz to be a problem and had no issue with quality of cut or flat bottoms using birdsbeak bits. I liked the back and forth motion of cutting mortises with BB bits. ?When I first got the FD250 I used to cut a lot of loose tenon joinery and toward the end of having a shop I cut mortises for locking mechanisms on on doors and windows. ?I moved to dowels for the joinery.
Calibration is critical.
Workholding is critical to good results too. ?Adding pneumatic clamps makes the FD250 much faster and helps to get better results. ?I would get pneumatic clamps before I would add a VFD if better results are what you are looking for. ?
If anything I though being able to run more slowly to use Forstner bits would have been nice. ?I did run Forstner bits up to 2 3/8" knowing that they could fail at any minute. ?I was ready with the off switch and had good luck to avoid failure.
John Ferandin and I looked for a Spindle motor to replace the FD250 motor but did not have success as the motors that would spin slowly enough for large bits and still have power were large and expensive. ?Another limiting factor of spindle motors was the size of the collet that was available for a given HP of motor. ?Small spindle motors that would be nice for the FD250 usually had an ER collet of 25 which mould not accommodate a large enough shank size. ?Motors that had an ER32 collet became too responsive to make the mod worth it.?
Hess makes horizontal mortisers with very nice features. ? I looked at lots of companies offerings at LIGNA year after year. ?It seems that the balancing act is between cost and moving to a CNC router. ?If you are going to spend $30k on a horizontal mortiser then moving to a router with much greater capability is reasonable. ?If you are making the same thing over and over like windows and doors then the dedicated horizontal mortiser will probably work better but will be less flexible. ?
As hobbyists with money to spend on very nice industrial machines the flexibility vs dedicated use creates conflicts with machines to add to our shops.
Joe
Brian,
My results were fine with 14mm in Cypress but I took small steps. If endmill won’t allow a bigger step (depth of cut per pass) then i have no interest unless it was cheaper and bits would last longer. I don’t know if end mills can be sharpened but no luck finding anyone to sharpen birdsmouth.
The previous owner demo in hard maple was not good. I don’t plan to get carbide but wanted to compare apples to apples.?
20mm birdsmouth in HSS is still over $100.
Lastly, my perception is that i will get clean bottom holes with end mills. Not sure if that is true.
Imran On Jan 30, 2021, at 11:41 AM, Brian Lamb < blamb11@...> wrote: ? Are your existing results bad? I doubt it. I wouldn’t spend the money on carbide for the occasional mortise… a 3/4” carbide extended length end mill will set you back north of $100 and carbide is pretty easy to snap off, especially on these comparatively flexible and rickety machines we are talking about. It would be a different story on a 10,000lb machining center.
Your best bet for 3/4” mortises would be an extended length HSS or Cobalt end mill. 4 flute would be stiffer, but because of less room for chip evacuation, it will tend to burn more, so I’d probably try a 2 flute version… stiffness in wood isn’t the big issue anyway.
I just want to try and see if better results can be had. Jonathan mentioned center cutting, 4 flute end mills. Does anyone have a recommendation for 3/4” end mill? Felder supplied birds mouth is 100mm long for 20mm.
Generic end mills may be more affordable as well. Felder 18mm HW is $150.
Imran?
On Jan 30, 2021, at 11:07 AM, Brian Lamb < blamb11@...> wrote: ? VFD rated motors can generally run up to 200hz, CNC router motors up to 400hz. Torque does drop dramatically over about 90hz.?
OK, I’ll probably start a war… but you don’t need huge rpm on router bits or on these mortisers. You can’t manually move the cutters at a rate that justifies all this rpm, all you will get is burning. Now, on a CNC router, different story, it has the capability to move the cutters at 500-1000ipm and can make use of all that rpm. I have machined mortises on my old Deckel mill and routinely done them at 1200 rpm and they come out great.?
On Jan 30, 2021, at 7:54 AM, David Kumm < davekumm@...> wrote:
Given the FD is direct drive, I would think the speed is closer to 3400 in the 60 hz market.? Generally you can overspeed a 2 pole motor to about 90 hz assuming the motor is decent quality.? Downside is that torque will be reduced because you aren't maintaining the volts/hz ratio.? The benefit and need for higher speed is really for small diameter bits so the reduction in torque might not be a big deal.? 5/8" bits are not a great choice for more speed and less torque.
4 pole or 6 pole motors are good for higher hz and vector duty motors are good for something like 5000-6000 rpm or up to 240 hz.? When you do that you usually oversize the motor to compensate for the loss of torque on the high end.? You also need to realize you may have way more torque on the low end than what the machine is designed for so care must be taken.??
Thank?Brian for straightening me out on this years ago when we had a discussion here about Rong Fu mills.? Dave
After realizing that people have used end mills on their mortising attachment, I was curious if there is a way to increase the RPM of FD250. The bit on morticing attachment is likely running around 5000 RPM, whereas FD250 is around 3000 RPM.
This article says it can be done as long as motor does not exceed it’s FLA, is not electrically overloaded and operating with it’s mechanical design limits.
Anyone got an idea how much more speed might be possible?
Electrical parts can be measured but I have no clue on mechanical side of what margin might exist.
This may not result in anything meaningful but I like to learn. One thing leads to another ....
Imran
|
Re: Increasing Motor RPM via VFD
Here is video of the FD250 cutting a mortise with Pneumatic clamps and carbide birdsbeak bit.
Joe
|
Re: Increasing Motor RPM via VFD
Brian,
Not having a reference or working experience makes it difficult to determine what you is good or not. Buying used machine with used bits (previous owner had a small business) another uncertainty. I do know that plunging as you said and cleaning after sounds like a lot faster than my current experience of side to side slitting in small steps.
Imran?
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On Jan 30, 2021, at 12:41 PM, Brian Lamb <blamb11@...> wrote: ? I don’t know that end mills will be any different in depth of cut on side to side passes, but they will plunge better than a birdsmouth bit. I’ve done mortises where you plunge 2” deep, step over 1/2 the diameter of the cutter, do it again, then when the whole mortise is plunged, finish it side to side at about 1” depth per pass, that’s with a 1/2” cutter.
You will get clean bottoms with either cutter, no difference there as long as you are sliding side to side at the bottom.?
Sharpening? How many thousands of mortises do you intend to do? Even a cheap HSS end mill should cut close to a thousand mortises before it gets dull… that would be a lifetime of mortises for me.
Brian,
My results were fine with 14mm in Cypress but I took small steps. If endmill won’t allow a bigger step (depth of cut per pass) then i have no interest unless it was cheaper and bits would last longer. I don’t know if end mills can be sharpened but no luck finding anyone to sharpen birdsmouth.
The previous owner demo in hard maple was not good. I don’t plan to get carbide but wanted to compare apples to apples.?
20mm birdsmouth in HSS is still over $100.
Lastly, my perception is that i will get clean bottom holes with end mills. Not sure if that is true.
Imran On Jan 30, 2021, at 11:41 AM, Brian Lamb < blamb11@...> wrote: ? Are your existing results bad? I doubt it. I wouldn’t spend the money on carbide for the occasional mortise… a 3/4” carbide extended length end mill will set you back north of $100 and carbide is pretty easy to snap off, especially on these comparatively flexible and rickety machines we are talking about. It would be a different story on a 10,000lb machining center.
Your best bet for 3/4” mortises would be an extended length HSS or Cobalt end mill. 4 flute would be stiffer, but because of less room for chip evacuation, it will tend to burn more, so I’d probably try a 2 flute version… stiffness in wood isn’t the big issue anyway.
I just want to try and see if better results can be had. Jonathan mentioned center cutting, 4 flute end mills. Does anyone have a recommendation for 3/4” end mill? Felder supplied birds mouth is 100mm long for 20mm.
Generic end mills may be more affordable as well. Felder 18mm HW is $150.
Imran?
On Jan 30, 2021, at 11:07 AM, Brian Lamb < blamb11@...> wrote: ? VFD rated motors can generally run up to 200hz, CNC router motors up to 400hz. Torque does drop dramatically over about 90hz.?
OK, I’ll probably start a war… but you don’t need huge rpm on router bits or on these mortisers. You can’t manually move the cutters at a rate that justifies all this rpm, all you will get is burning. Now, on a CNC router, different story, it has the capability to move the cutters at 500-1000ipm and can make use of all that rpm. I have machined mortises on my old Deckel mill and routinely done them at 1200 rpm and they come out great.?
On Jan 30, 2021, at 7:54 AM, David Kumm < davekumm@...> wrote:
Given the FD is direct drive, I would think the speed is closer to 3400 in the 60 hz market.? Generally you can overspeed a 2 pole motor to about 90 hz assuming the motor is decent quality.? Downside is that torque will be reduced because you aren't maintaining the volts/hz ratio.? The benefit and need for higher speed is really for small diameter bits so the reduction in torque might not be a big deal.? 5/8" bits are not a great choice for more speed and less torque.
4 pole or 6 pole motors are good for higher hz and vector duty motors are good for something like 5000-6000 rpm or up to 240 hz.? When you do that you usually oversize the motor to compensate for the loss of torque on the high end.? You also need to realize you may have way more torque on the low end than what the machine is designed for so care must be taken.??
Thank?Brian for straightening me out on this years ago when we had a discussion here about Rong Fu mills.? Dave
After realizing that people have used end mills on their mortising attachment, I was curious if there is a way to increase the RPM of FD250. The bit on morticing attachment is likely running around 5000 RPM, whereas FD250 is around 3000 RPM.
This article says it can be done as long as motor does not exceed it’s FLA, is not electrically overloaded and operating with it’s mechanical design limits.
Anyone got an idea how much more speed might be possible?
Electrical parts can be measured but I have no clue on mechanical side of what margin might exist.
This may not result in anything meaningful but I like to learn. One thing leads to another ....
Imran
|
Re: Increasing Motor RPM via VFD
I did not find the speed with the FD250 at 60 Hz to be a problem and had no issue with quality of cut or flat bottoms using birdsbeak bits. I liked the back and forth motion of cutting mortises with BB bits. ?When I first got the FD250 I used to cut a lot of loose tenon joinery and toward the end of having a shop I cut mortises for locking mechanisms on on doors and windows. ?I moved to dowels for the joinery.
Calibration is critical.
Workholding is critical to good results too. ?Adding pneumatic clamps makes the FD250 much faster and helps to get better results. ?I would get pneumatic clamps before I would add a VFD if better results are what you are looking for. ?
If anything I though being able to run more slowly to use Forstner bits would have been nice. ?I did run Forstner bits up to 2 3/8" knowing that they could fail at any minute. ?I was ready with the off switch and had good luck to avoid failure.
John Ferandin and I looked for a Spindle motor to replace the FD250 motor but did not have success as the motors that would spin slowly enough for large bits and still have power were large and expensive. ?Another limiting factor of spindle motors was the size of the collet that was available for a given HP of motor. ?Small spindle motors that would be nice for the FD250 usually had an ER collet of 25 which mould not accommodate a large enough shank size. ?Motors that had an ER32 collet became too responsive to make the mod worth it.?
Hess makes horizontal mortisers with very nice features. ? I looked at lots of companies offerings at LIGNA year after year. ?It seems that the balancing act is between cost and moving to a CNC router. ?If you are going to spend $30k on a horizontal mortiser then moving to a router with much greater capability is reasonable. ?If you are making the same thing over and over like windows and doors then the dedicated horizontal mortiser will probably work better but will be less flexible. ?
As hobbyists with money to spend on very nice industrial machines the flexibility vs dedicated use creates conflicts with machines to add to our shops.
Joe
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Show quoted text
Brian,
My results were fine with 14mm in Cypress but I took small steps. If endmill won’t allow a bigger step (depth of cut per pass) then i have no interest unless it was cheaper and bits would last longer. I don’t know if end mills can be sharpened but no luck finding anyone to sharpen birdsmouth.
The previous owner demo in hard maple was not good. I don’t plan to get carbide but wanted to compare apples to apples.?
20mm birdsmouth in HSS is still over $100.
Lastly, my perception is that i will get clean bottom holes with end mills. Not sure if that is true.
Imran On Jan 30, 2021, at 11:41 AM, Brian Lamb < blamb11@...> wrote: ? Are your existing results bad? I doubt it. I wouldn’t spend the money on carbide for the occasional mortise… a 3/4” carbide extended length end mill will set you back north of $100 and carbide is pretty easy to snap off, especially on these comparatively flexible and rickety machines we are talking about. It would be a different story on a 10,000lb machining center.
Your best bet for 3/4” mortises would be an extended length HSS or Cobalt end mill. 4 flute would be stiffer, but because of less room for chip evacuation, it will tend to burn more, so I’d probably try a 2 flute version… stiffness in wood isn’t the big issue anyway.
I just want to try and see if better results can be had. Jonathan mentioned center cutting, 4 flute end mills. Does anyone have a recommendation for 3/4” end mill? Felder supplied birds mouth is 100mm long for 20mm.
Generic end mills may be more affordable as well. Felder 18mm HW is $150.
Imran?
On Jan 30, 2021, at 11:07 AM, Brian Lamb < blamb11@...> wrote: ? VFD rated motors can generally run up to 200hz, CNC router motors up to 400hz. Torque does drop dramatically over about 90hz.?
OK, I’ll probably start a war… but you don’t need huge rpm on router bits or on these mortisers. You can’t manually move the cutters at a rate that justifies all this rpm, all you will get is burning. Now, on a CNC router, different story, it has the capability to move the cutters at 500-1000ipm and can make use of all that rpm. I have machined mortises on my old Deckel mill and routinely done them at 1200 rpm and they come out great.?
On Jan 30, 2021, at 7:54 AM, David Kumm < davekumm@...> wrote:
Given the FD is direct drive, I would think the speed is closer to 3400 in the 60 hz market.? Generally you can overspeed a 2 pole motor to about 90 hz assuming the motor is decent quality.? Downside is that torque will be reduced because you aren't maintaining the volts/hz ratio.? The benefit and need for higher speed is really for small diameter bits so the reduction in torque might not be a big deal.? 5/8" bits are not a great choice for more speed and less torque.
4 pole or 6 pole motors are good for higher hz and vector duty motors are good for something like 5000-6000 rpm or up to 240 hz.? When you do that you usually oversize the motor to compensate for the loss of torque on the high end.? You also need to realize you may have way more torque on the low end than what the machine is designed for so care must be taken.??
Thank?Brian for straightening me out on this years ago when we had a discussion here about Rong Fu mills.? Dave
After realizing that people have used end mills on their mortising attachment, I was curious if there is a way to increase the RPM of FD250. The bit on morticing attachment is likely running around 5000 RPM, whereas FD250 is around 3000 RPM.
This article says it can be done as long as motor does not exceed it’s FLA, is not electrically overloaded and operating with it’s mechanical design limits.
Anyone got an idea how much more speed might be possible?
Electrical parts can be measured but I have no clue on mechanical side of what margin might exist.
This may not result in anything meaningful but I like to learn. One thing leads to another ....
Imran
|
Re: Felder Feeder for Sale
Good price, you might mention where you are… shipping could kill the deal.
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I bought this a few years ago but it was too big and heavy a feeder to mount on my Hammer C 331, so I never used it. The fellow I bought it from also had a home workshop. He used it very little; hardly at all? he said. It is in good working condition. It has the tilting device and extension horzontal tube. I hope the photos give most of the info you need, but I can get you more. I have the manuals etc. I want to get $550. U.S for it. <20210122_151251.jpg>
<20210122_151200.jpg>
<20210122_151251.jpg><20210122_151200.jpg>
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Re: Increasing Motor RPM via VFD
I don’t know that end mills will be any different in depth of cut on side to side passes, but they will plunge better than a birdsmouth bit. I’ve done mortises where you plunge 2” deep, step over 1/2 the diameter of the cutter, do it again, then when the whole mortise is plunged, finish it side to side at about 1” depth per pass, that’s with a 1/2” cutter.
You will get clean bottoms with either cutter, no difference there as long as you are sliding side to side at the bottom.?
Sharpening? How many thousands of mortises do you intend to do? Even a cheap HSS end mill should cut close to a thousand mortises before it gets dull… that would be a lifetime of mortises for me.
toggle quoted message
Show quoted text
Brian,
My results were fine with 14mm in Cypress but I took small steps. If endmill won’t allow a bigger step (depth of cut per pass) then i have no interest unless it was cheaper and bits would last longer. I don’t know if end mills can be sharpened but no luck finding anyone to sharpen birdsmouth.
The previous owner demo in hard maple was not good. I don’t plan to get carbide but wanted to compare apples to apples.?
20mm birdsmouth in HSS is still over $100.
Lastly, my perception is that i will get clean bottom holes with end mills. Not sure if that is true.
Imran On Jan 30, 2021, at 11:41 AM, Brian Lamb < blamb11@...> wrote: ? Are your existing results bad? I doubt it. I wouldn’t spend the money on carbide for the occasional mortise… a 3/4” carbide extended length end mill will set you back north of $100 and carbide is pretty easy to snap off, especially on these comparatively flexible and rickety machines we are talking about. It would be a different story on a 10,000lb machining center.
Your best bet for 3/4” mortises would be an extended length HSS or Cobalt end mill. 4 flute would be stiffer, but because of less room for chip evacuation, it will tend to burn more, so I’d probably try a 2 flute version… stiffness in wood isn’t the big issue anyway.
I just want to try and see if better results can be had. Jonathan mentioned center cutting, 4 flute end mills. Does anyone have a recommendation for 3/4” end mill? Felder supplied birds mouth is 100mm long for 20mm.
Generic end mills may be more affordable as well. Felder 18mm HW is $150.
Imran?
On Jan 30, 2021, at 11:07 AM, Brian Lamb < blamb11@...> wrote: ? VFD rated motors can generally run up to 200hz, CNC router motors up to 400hz. Torque does drop dramatically over about 90hz.?
OK, I’ll probably start a war… but you don’t need huge rpm on router bits or on these mortisers. You can’t manually move the cutters at a rate that justifies all this rpm, all you will get is burning. Now, on a CNC router, different story, it has the capability to move the cutters at 500-1000ipm and can make use of all that rpm. I have machined mortises on my old Deckel mill and routinely done them at 1200 rpm and they come out great.?
On Jan 30, 2021, at 7:54 AM, David Kumm < davekumm@...> wrote:
Given the FD is direct drive, I would think the speed is closer to 3400 in the 60 hz market.? Generally you can overspeed a 2 pole motor to about 90 hz assuming the motor is decent quality.? Downside is that torque will be reduced because you aren't maintaining the volts/hz ratio.? The benefit and need for higher speed is really for small diameter bits so the reduction in torque might not be a big deal.? 5/8" bits are not a great choice for more speed and less torque.
4 pole or 6 pole motors are good for higher hz and vector duty motors are good for something like 5000-6000 rpm or up to 240 hz.? When you do that you usually oversize the motor to compensate for the loss of torque on the high end.? You also need to realize you may have way more torque on the low end than what the machine is designed for so care must be taken.??
Thank?Brian for straightening me out on this years ago when we had a discussion here about Rong Fu mills.? Dave
After realizing that people have used end mills on their mortising attachment, I was curious if there is a way to increase the RPM of FD250. The bit on morticing attachment is likely running around 5000 RPM, whereas FD250 is around 3000 RPM.
This article says it can be done as long as motor does not exceed it’s FLA, is not electrically overloaded and operating with it’s mechanical design limits.
Anyone got an idea how much more speed might be possible?
Electrical parts can be measured but I have no clue on mechanical side of what margin might exist.
This may not result in anything meaningful but I like to learn. One thing leads to another ....
Imran
|
Re: Increasing Motor RPM via VFD
Some have electric fans, some have motor mounted fans. My 5hp mill has a motor mounted fan, my son has a 7.5hp mill and his has electric fans. Most VFD rated motors have heavier windings and insulation to deal with extra heat, as I said below.
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I thought they also have fan control so fan can run appropriate speed at low RPM.
Imran On Jan 30, 2021, at 11:43 AM, Brian Lamb < blamb11@...> wrote: ? I don’t think balance is the issue, the VFD rated motors are heavier windings and shellac on the windings, the higher frequencies tend to break down the insulation on the motors and overheat them.
On Jan 30, 2021, at 9:23 AM, David Kumm < davekumm@...> wrote:
That brings up the question, are inverter duty motors balanced for higher speeds than regular motors?? The standard is 125% of rated speed for 2 pole motors or 75 hz.? 4 pole motors are generally balanced to the same specs as 2 pole so in effect to 150 hz.?
My 1800 rpm motor is rated to 6000 rpm, but that is noted on the plate.? Dave
VFD rated motors can generally run up to 200hz, CNC router motors up to 400hz. Torque does drop dramatically over about 90hz.?
OK, I’ll probably start a war… but you don’t need huge rpm on router bits or on these mortisers. You can’t manually move the cutters at a rate that justifies all this rpm, all you will get is burning. Now, on a CNC router, different story, it
has the capability to move the cutters at 500-1000ipm and can make use of all that rpm. I have machined mortises on my old Deckel mill and routinely done them at 1200 rpm and they come out great.?
On Jan 30, 2021, at 7:54 AM, David Kumm < davekumm@...> wrote:
Given the FD is direct drive, I would think the speed is closer to 3400 in the 60 hz market.? Generally you can overspeed a 2 pole motor to about 90 hz assuming the motor is decent quality.? Downside is that torque will be reduced because you aren't maintaining
the volts/hz ratio.? The benefit and need for higher speed is really for small diameter bits so the reduction in torque might not be a big deal.? 5/8" bits are not a great choice for more speed and less torque.
4 pole or 6 pole motors are good for higher hz and vector duty motors are good for something like 5000-6000 rpm or up to 240 hz.? When you do that you usually oversize the motor to compensate for the loss of torque on the high end.? You also need to realize
you may have way more torque on the low end than what the machine is designed for so care must be taken.??
Thank?Brian for straightening me out on this years ago when we had a discussion here about Rong Fu mills.? Dave
After realizing that people have used end mills on their mortising attachment, I was curious if there is a way to increase the RPM of FD250. The bit on morticing attachment is likely running around 5000 RPM, whereas FD250 is around
3000 RPM.
This article says it can be done as long as motor does not exceed it’s FLA, is not electrically overloaded and operating with it’s mechanical design limits.
Anyone got an idea how much more speed might be possible?
Electrical parts can be measured but I have no clue on mechanical side of what margin might exist.
This may not result in anything meaningful but I like to learn. One thing leads to another ....
Imran
|
I bought this a few years ago but it was too big and heavy a feeder to mount on my Hammer C 331, so I never used it. The fellow I bought it from also had a home workshop. He used it very little; hardly at all? he said. It is in good working condition. It has the tilting device and extension horzontal tube. I hope the photos give most of the info you need, but I can get you more. I have the manuals etc. I want to get $550. U.S for it.
|
Re: Increasing Motor RPM via VFD
Brian,
My results were fine with 14mm in Cypress but I took small steps. If endmill won’t allow a bigger step (depth of cut per pass) then i have no interest unless it was cheaper and bits would last longer. I don’t know if end mills can be sharpened but no luck finding anyone to sharpen birdsmouth.
The previous owner demo in hard maple was not good. I don’t plan to get carbide but wanted to compare apples to apples.?
20mm birdsmouth in HSS is still over $100.
Lastly, my perception is that i will get clean bottom holes with end mills. Not sure if that is true.
Imran
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On Jan 30, 2021, at 11:41 AM, Brian Lamb <blamb11@...> wrote: ? Are your existing results bad? I doubt it. I wouldn’t spend the money on carbide for the occasional mortise… a 3/4” carbide extended length end mill will set you back north of $100 and carbide is pretty easy to snap off, especially on these comparatively flexible and rickety machines we are talking about. It would be a different story on a 10,000lb machining center.
Your best bet for 3/4” mortises would be an extended length HSS or Cobalt end mill. 4 flute would be stiffer, but because of less room for chip evacuation, it will tend to burn more, so I’d probably try a 2 flute version… stiffness in wood isn’t the big issue anyway.
I just want to try and see if better results can be had. Jonathan mentioned center cutting, 4 flute end mills. Does anyone have a recommendation for 3/4” end mill? Felder supplied birds mouth is 100mm long for 20mm.
Generic end mills may be more affordable as well. Felder 18mm HW is $150.
Imran?
On Jan 30, 2021, at 11:07 AM, Brian Lamb < blamb11@...> wrote: ? VFD rated motors can generally run up to 200hz, CNC router motors up to 400hz. Torque does drop dramatically over about 90hz.?
OK, I’ll probably start a war… but you don’t need huge rpm on router bits or on these mortisers. You can’t manually move the cutters at a rate that justifies all this rpm, all you will get is burning. Now, on a CNC router, different story, it has the capability to move the cutters at 500-1000ipm and can make use of all that rpm. I have machined mortises on my old Deckel mill and routinely done them at 1200 rpm and they come out great.?
On Jan 30, 2021, at 7:54 AM, David Kumm < davekumm@...> wrote:
Given the FD is direct drive, I would think the speed is closer to 3400 in the 60 hz market.? Generally you can overspeed a 2 pole motor to about 90 hz assuming the motor is decent quality.? Downside is that torque will be reduced because you aren't maintaining the volts/hz ratio.? The benefit and need for higher speed is really for small diameter bits so the reduction in torque might not be a big deal.? 5/8" bits are not a great choice for more speed and less torque.
4 pole or 6 pole motors are good for higher hz and vector duty motors are good for something like 5000-6000 rpm or up to 240 hz.? When you do that you usually oversize the motor to compensate for the loss of torque on the high end.? You also need to realize you may have way more torque on the low end than what the machine is designed for so care must be taken.??
Thank?Brian for straightening me out on this years ago when we had a discussion here about Rong Fu mills.? Dave
After realizing that people have used end mills on their mortising attachment, I was curious if there is a way to increase the RPM of FD250. The bit on morticing attachment is likely running around 5000 RPM, whereas FD250 is around 3000 RPM.
This article says it can be done as long as motor does not exceed it’s FLA, is not electrically overloaded and operating with it’s mechanical design limits.
Anyone got an idea how much more speed might be possible?
Electrical parts can be measured but I have no clue on mechanical side of what margin might exist.
This may not result in anything meaningful but I like to learn. One thing leads to another ....
Imran
|
Re: Increasing Motor RPM via VFD
Inverter duty does deal with the winding and insulation issues but the mechanical limits of higher speed must also be factored.? 4500 rpm seems to be the standard for at least 2 and 4 pole motors.? I'm wondering if inverter duty raises that limit.? Vector duty,
in addition to reducing the safe hz limit to something like .06 hz on the bottom, also increases the speed limit which is often on the plate.? Dave
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I don’t think balance is the issue, the VFD rated motors are heavier windings and shellac on the windings, the higher frequencies tend to break down the insulation on the motors and overheat them.
On Jan 30, 2021, at 9:23 AM, David Kumm < davekumm@...> wrote:
That brings up the question, are inverter duty motors balanced for higher speeds than regular motors?? The standard is 125% of rated speed for 2 pole motors or 75 hz.? 4 pole motors
are generally balanced to the same specs as 2 pole so in effect to 150 hz.? My 1800 rpm motor is rated to 6000 rpm, but that is noted on the plate.? Dave
VFD rated motors can generally run up to 200hz, CNC router motors up to 400hz. Torque does drop dramatically over about 90hz.?
OK, I’ll probably start a war… but you don’t need huge rpm on router bits or on these mortisers. You can’t manually move the cutters at a rate that justifies all this rpm, all you will get is burning. Now, on a CNC router, different story, it
has the capability to move the cutters at 500-1000ipm and can make use of all that rpm. I have machined mortises on my old Deckel mill and routinely done them at 1200 rpm and they come out great.?
On Jan 30, 2021, at 7:54 AM, David Kumm < davekumm@...> wrote:
Given the FD is direct drive, I would think the speed is closer to 3400 in the 60 hz market.? Generally you can overspeed a 2 pole motor to about 90 hz assuming the motor is decent quality.? Downside is that torque will be reduced because you aren't maintaining
the volts/hz ratio.? The benefit and need for higher speed is really for small diameter bits so the reduction in torque might not be a big deal.? 5/8" bits are not a great choice for more speed and less torque.
4 pole or 6 pole motors are good for higher hz and vector duty motors are good for something like 5000-6000 rpm or up to 240 hz.? When you do that you usually oversize the motor to compensate for the loss of torque on the high end.? You also need to realize
you may have way more torque on the low end than what the machine is designed for so care must be taken.??
Thank?Brian for straightening me out on this years ago when we had a discussion here about Rong Fu mills.? Dave
After realizing that people have used end mills on their mortising attachment, I was curious if there is a way to increase the RPM of FD250. The bit on morticing attachment is likely running around 5000 RPM, whereas FD250 is around
3000 RPM.
This article says it can be done as long as motor does not exceed it’s FLA, is not electrically overloaded and operating with it’s mechanical design limits.
Anyone got an idea how much more speed might be possible?
Electrical parts can be measured but I have no clue on mechanical side of what margin might exist.
This may not result in anything meaningful but I like to learn. One thing leads to another ....
Imran
|
Re: Increasing Motor RPM via VFD
Fan cooled motors can have issued with low speed operation.? I've seen some people add a computer type fan that a vfd turns on when hz drops below a set amount to move air.? There are also motors that don't rely on fans to cool ( TENV is one ).? Dave
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I thought they also have fan control so fan can run appropriate speed at low RPM.
Imran
On Jan 30, 2021, at 11:43 AM, Brian Lamb <blamb11@...> wrote:
?I don’t think balance is the issue, the VFD rated motors are heavier windings and shellac on the windings, the higher frequencies tend to break down the insulation on the motors and overheat them.
On Jan 30, 2021, at 9:23 AM, David Kumm < davekumm@...> wrote:
That brings up the question, are inverter duty motors balanced for higher speeds than regular motors?? The standard is 125% of rated speed for 2 pole motors or 75 hz.? 4 pole motors
are generally balanced to the same specs as 2 pole so in effect to 150 hz.? My 1800 rpm motor is rated to 6000 rpm, but that is noted on the plate.? Dave
VFD rated motors can generally run up to 200hz, CNC router motors up to 400hz. Torque does drop dramatically over about 90hz.?
OK, I’ll probably start a war… but you don’t need huge rpm on router bits or on these mortisers. You can’t manually move the cutters at a rate that justifies all this rpm, all you will get is burning. Now, on a CNC router, different story, it
has the capability to move the cutters at 500-1000ipm and can make use of all that rpm. I have machined mortises on my old Deckel mill and routinely done them at 1200 rpm and they come out great.?
On Jan 30, 2021, at 7:54 AM, David Kumm < davekumm@...> wrote:
Given the FD is direct drive, I would think the speed is closer to 3400 in the 60 hz market.? Generally you can overspeed a 2 pole motor to about 90 hz assuming the motor is decent quality.? Downside is that torque will be reduced because you aren't maintaining
the volts/hz ratio.? The benefit and need for higher speed is really for small diameter bits so the reduction in torque might not be a big deal.? 5/8" bits are not a great choice for more speed and less torque.
4 pole or 6 pole motors are good for higher hz and vector duty motors are good for something like 5000-6000 rpm or up to 240 hz.? When you do that you usually oversize the motor to compensate for the loss of torque on the high end.? You also need to realize
you may have way more torque on the low end than what the machine is designed for so care must be taken.??
Thank?Brian for straightening me out on this years ago when we had a discussion here about Rong Fu mills.? Dave
After realizing that people have used end mills on their mortising attachment, I was curious if there is a way to increase the RPM of FD250. The bit on morticing attachment is likely running around 5000 RPM, whereas FD250 is around
3000 RPM.
This article says it can be done as long as motor does not exceed it’s FLA, is not electrically overloaded and operating with it’s mechanical design limits.
Anyone got an idea how much more speed might be possible?
Electrical parts can be measured but I have no clue on mechanical side of what margin might exist.
This may not result in anything meaningful but I like to learn. One thing leads to another ....
Imran
|
Re: Increasing Motor RPM via VFD
I thought they also have fan control so fan can run appropriate speed at low RPM.
Imran
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Show quoted text
On Jan 30, 2021, at 11:43 AM, Brian Lamb <blamb11@...> wrote: ? I don’t think balance is the issue, the VFD rated motors are heavier windings and shellac on the windings, the higher frequencies tend to break down the insulation on the motors and overheat them.
On Jan 30, 2021, at 9:23 AM, David Kumm < davekumm@...> wrote:
That brings up the question, are inverter duty motors balanced for higher speeds than regular motors?? The standard is 125% of rated speed for 2 pole motors or 75 hz.? 4 pole motors are generally balanced to the same specs as 2 pole so in effect to 150 hz.?
My 1800 rpm motor is rated to 6000 rpm, but that is noted on the plate.? Dave
VFD rated motors can generally run up to 200hz, CNC router motors up to 400hz. Torque does drop dramatically over about 90hz.?
OK, I’ll probably start a war… but you don’t need huge rpm on router bits or on these mortisers. You can’t manually move the cutters at a rate that justifies all this rpm, all you will get is burning. Now, on a CNC router, different story, it
has the capability to move the cutters at 500-1000ipm and can make use of all that rpm. I have machined mortises on my old Deckel mill and routinely done them at 1200 rpm and they come out great.?
On Jan 30, 2021, at 7:54 AM, David Kumm < davekumm@...> wrote:
Given the FD is direct drive, I would think the speed is closer to 3400 in the 60 hz market.? Generally you can overspeed a 2 pole motor to about 90 hz assuming the motor is decent quality.? Downside is that torque will be reduced because you aren't maintaining
the volts/hz ratio.? The benefit and need for higher speed is really for small diameter bits so the reduction in torque might not be a big deal.? 5/8" bits are not a great choice for more speed and less torque.
4 pole or 6 pole motors are good for higher hz and vector duty motors are good for something like 5000-6000 rpm or up to 240 hz.? When you do that you usually oversize the motor to compensate for the loss of torque on the high end.? You also need to realize
you may have way more torque on the low end than what the machine is designed for so care must be taken.??
Thank?Brian for straightening me out on this years ago when we had a discussion here about Rong Fu mills.? Dave
After realizing that people have used end mills on their mortising attachment, I was curious if there is a way to increase the RPM of FD250. The bit on morticing attachment is likely running around 5000 RPM, whereas FD250 is around
3000 RPM.
This article says it can be done as long as motor does not exceed it’s FLA, is not electrically overloaded and operating with it’s mechanical design limits.
Anyone got an idea how much more speed might be possible?
Electrical parts can be measured but I have no clue on mechanical side of what margin might exist.
This may not result in anything meaningful but I like to learn. One thing leads to another ....
Imran
|
Re: Increasing Motor RPM via VFD
I’m sure Amana or Onsrud will have cutting data on their cutters for wood. You don’t have enough rpm to run the theoretical amounts for wood, none of us do. I’ll say it again, what’s the problem with running slower? You get less burning, better finishes and less chatter.
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David,
My machine label says 50 Hz. I remember speaking to Felder about it and perhaps mentioned it here as well but was told it should be fine. I will check the motor label when I am in shop to see if it states RPM specific to Hz.
It is hard to find end mill info for wood. I found this for uncoated carbide (requiring lowest RPM). If wood equates to plastics than 3/4” bit equates to 4100 RPM. So I may be able to try end mills on my FD250 for larger dia. Not sure if they are produced in lengths needed for FD250.
<image0.jpeg>
I know this is a much deeper subject.
Imran On Jan 30, 2021, at 9:55 AM, David Kumm < davekumm@...> wrote: ?
Given the FD is direct drive, I would think the speed is closer to 3400 in the 60 hz market.? Generally you can overspeed a 2 pole motor to about 90 hz assuming the motor is decent quality.? Downside is that torque will be reduced because you aren't maintaining
the volts/hz ratio.? The benefit and need for higher speed is really for small diameter bits so the reduction in torque might not be a big deal.? 5/8" bits are not a great choice for more speed and less torque.
4 pole or 6 pole motors are good for higher hz and vector duty motors are good for something like 5000-6000 rpm or up to 240 hz.? When you do that you usually oversize the motor to compensate for the loss of torque on the high end.? You also need to realize
you may have way more torque on the low end than what the machine is designed for so care must be taken.?
Thank Brian for straightening me out on this years ago when we had a discussion here about Rong Fu mills.? Dave
After realizing that people have used end mills on their mortising attachment, I was curious if there is a way to increase the RPM of FD250. The bit on morticing attachment is likely running around 5000 RPM, whereas FD250 is around 3000 RPM.
This article says it can be done as long as motor does not exceed it’s FLA, is not electrically overloaded and operating with it’s mechanical design limits.
Anyone got an idea how much more speed might be possible?
Electrical parts can be measured but I have no clue on mechanical side of what margin might exist.
This may not result in anything meaningful but I like to learn. One thing leads to another ....
Imran
|
Re: Increasing Motor RPM via VFD
I don’t think balance is the issue, the VFD rated motors are heavier windings and shellac on the windings, the higher frequencies tend to break down the insulation on the motors and overheat them.
toggle quoted message
Show quoted text
On Jan 30, 2021, at 9:23 AM, David Kumm < davekumm@...> wrote:
That brings up the question, are inverter duty motors balanced for higher speeds than regular motors?? The standard is 125% of rated speed for 2 pole motors or 75 hz.? 4 pole motors are generally balanced to the same specs as 2 pole so in effect to 150 hz.?
My 1800 rpm motor is rated to 6000 rpm, but that is noted on the plate.? Dave
VFD rated motors can generally run up to 200hz, CNC router motors up to 400hz. Torque does drop dramatically over about 90hz.?
OK, I’ll probably start a war… but you don’t need huge rpm on router bits or on these mortisers. You can’t manually move the cutters at a rate that justifies all this rpm, all you will get is burning. Now, on a CNC router, different story, it
has the capability to move the cutters at 500-1000ipm and can make use of all that rpm. I have machined mortises on my old Deckel mill and routinely done them at 1200 rpm and they come out great.?
On Jan 30, 2021, at 7:54 AM, David Kumm < davekumm@...> wrote:
Given the FD is direct drive, I would think the speed is closer to 3400 in the 60 hz market.? Generally you can overspeed a 2 pole motor to about 90 hz assuming the motor is decent quality.? Downside is that torque will be reduced because you aren't maintaining
the volts/hz ratio.? The benefit and need for higher speed is really for small diameter bits so the reduction in torque might not be a big deal.? 5/8" bits are not a great choice for more speed and less torque.
4 pole or 6 pole motors are good for higher hz and vector duty motors are good for something like 5000-6000 rpm or up to 240 hz.? When you do that you usually oversize the motor to compensate for the loss of torque on the high end.? You also need to realize
you may have way more torque on the low end than what the machine is designed for so care must be taken.??
Thank?Brian for straightening me out on this years ago when we had a discussion here about Rong Fu mills.? Dave
After realizing that people have used end mills on their mortising attachment, I was curious if there is a way to increase the RPM of FD250. The bit on morticing attachment is likely running around 5000 RPM, whereas FD250 is around
3000 RPM.
This article says it can be done as long as motor does not exceed it’s FLA, is not electrically overloaded and operating with it’s mechanical design limits.
Anyone got an idea how much more speed might be possible?
Electrical parts can be measured but I have no clue on mechanical side of what margin might exist.
This may not result in anything meaningful but I like to learn. One thing leads to another ....
Imran
|
Re: Increasing Motor RPM via VFD
Are your existing results bad? I doubt it. I wouldn’t spend the money on carbide for the occasional mortise… a 3/4” carbide extended length end mill will set you back north of $100 and carbide is pretty easy to snap off, especially on these comparatively flexible and rickety machines we are talking about. It would be a different story on a 10,000lb machining center.
Your best bet for 3/4” mortises would be an extended length HSS or Cobalt end mill. 4 flute would be stiffer, but because of less room for chip evacuation, it will tend to burn more, so I’d probably try a 2 flute version… stiffness in wood isn’t the big issue anyway.
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Show quoted text
I just want to try and see if better results can be had. Jonathan mentioned center cutting, 4 flute end mills. Does anyone have a recommendation for 3/4” end mill? Felder supplied birds mouth is 100mm long for 20mm.
Generic end mills may be more affordable as well. Felder 18mm HW is $150.
Imran?
On Jan 30, 2021, at 11:07 AM, Brian Lamb < blamb11@...> wrote: ? VFD rated motors can generally run up to 200hz, CNC router motors up to 400hz. Torque does drop dramatically over about 90hz.?
OK, I’ll probably start a war… but you don’t need huge rpm on router bits or on these mortisers. You can’t manually move the cutters at a rate that justifies all this rpm, all you will get is burning. Now, on a CNC router, different story, it has the capability to move the cutters at 500-1000ipm and can make use of all that rpm. I have machined mortises on my old Deckel mill and routinely done them at 1200 rpm and they come out great.?
On Jan 30, 2021, at 7:54 AM, David Kumm < davekumm@...> wrote:
Given the FD is direct drive, I would think the speed is closer to 3400 in the 60 hz market.? Generally you can overspeed a 2 pole motor to about 90 hz assuming the motor is decent quality.? Downside is that torque will be reduced because you aren't maintaining the volts/hz ratio.? The benefit and need for higher speed is really for small diameter bits so the reduction in torque might not be a big deal.? 5/8" bits are not a great choice for more speed and less torque.
4 pole or 6 pole motors are good for higher hz and vector duty motors are good for something like 5000-6000 rpm or up to 240 hz.? When you do that you usually oversize the motor to compensate for the loss of torque on the high end.? You also need to realize you may have way more torque on the low end than what the machine is designed for so care must be taken.??
Thank?Brian for straightening me out on this years ago when we had a discussion here about Rong Fu mills.? Dave
After realizing that people have used end mills on their mortising attachment, I was curious if there is a way to increase the RPM of FD250. The bit on morticing attachment is likely running around 5000 RPM, whereas FD250 is around 3000 RPM.
This article says it can be done as long as motor does not exceed it’s FLA, is not electrically overloaded and operating with it’s mechanical design limits.
Anyone got an idea how much more speed might be possible?
Electrical parts can be measured but I have no clue on mechanical side of what margin might exist.
This may not result in anything meaningful but I like to learn. One thing leads to another ....
Imran
|
Re: Increasing Motor RPM via VFD
I just want to try and see if better results can be had. Jonathan mentioned center cutting, 4 flute end mills. Does anyone have a recommendation for 3/4” end mill? Felder supplied birds mouth is 100mm long for 20mm.
Generic end mills may be more affordable as well. Felder 18mm HW is $150.
Imran?
toggle quoted message
Show quoted text
On Jan 30, 2021, at 11:07 AM, Brian Lamb <blamb11@...> wrote: ? VFD rated motors can generally run up to 200hz, CNC router motors up to 400hz. Torque does drop dramatically over about 90hz.?
OK, I’ll probably start a war… but you don’t need huge rpm on router bits or on these mortisers. You can’t manually move the cutters at a rate that justifies all this rpm, all you will get is burning. Now, on a CNC router, different story, it has the capability to move the cutters at 500-1000ipm and can make use of all that rpm. I have machined mortises on my old Deckel mill and routinely done them at 1200 rpm and they come out great.?
On Jan 30, 2021, at 7:54 AM, David Kumm < davekumm@...> wrote:
Given the FD is direct drive, I would think the speed is closer to 3400 in the 60 hz market.? Generally you can overspeed a 2 pole motor to about 90 hz assuming the motor is decent quality.? Downside is that torque will be reduced because you aren't maintaining the volts/hz ratio.? The benefit and need for higher speed is really for small diameter bits so the reduction in torque might not be a big deal.? 5/8" bits are not a great choice for more speed and less torque.
4 pole or 6 pole motors are good for higher hz and vector duty motors are good for something like 5000-6000 rpm or up to 240 hz.? When you do that you usually oversize the motor to compensate for the loss of torque on the high end.? You also need to realize you may have way more torque on the low end than what the machine is designed for so care must be taken.??
Thank?Brian for straightening me out on this years ago when we had a discussion here about Rong Fu mills.? Dave
After realizing that people have used end mills on their mortising attachment, I was curious if there is a way to increase the RPM of FD250. The bit on morticing attachment is likely running around 5000 RPM, whereas FD250 is around 3000 RPM.
This article says it can be done as long as motor does not exceed it’s FLA, is not electrically overloaded and operating with it’s mechanical design limits.
Anyone got an idea how much more speed might be possible?
Electrical parts can be measured but I have no clue on mechanical side of what margin might exist.
This may not result in anything meaningful but I like to learn. One thing leads to another ....
Imran
|
Re: Increasing Motor RPM via VFD
That brings up the question, are inverter duty motors balanced for higher speeds than regular motors?? The standard is 125% of rated speed for 2 pole motors or 75 hz.? 4 pole motors are generally balanced to the same specs as 2 pole so in effect to 150 hz.?
My 1800 rpm motor is rated to 6000 rpm, but that is noted on the plate.? Dave
toggle quoted message
Show quoted text
VFD rated motors can generally run up to 200hz, CNC router motors up to 400hz. Torque does drop dramatically over about 90hz.?
OK, I’ll probably start a war… but you don’t need huge rpm on router bits or on these mortisers. You can’t manually move the cutters at a rate that justifies all this rpm, all you will get is burning. Now, on a CNC router, different story, it
has the capability to move the cutters at 500-1000ipm and can make use of all that rpm. I have machined mortises on my old Deckel mill and routinely done them at 1200 rpm and they come out great.?
On Jan 30, 2021, at 7:54 AM, David Kumm < davekumm@...> wrote:
Given the FD is direct drive, I would think the speed is closer to 3400 in the 60 hz market.? Generally you can overspeed a 2 pole motor to about 90 hz assuming the motor is decent quality.? Downside is that torque will be reduced because you aren't maintaining
the volts/hz ratio.? The benefit and need for higher speed is really for small diameter bits so the reduction in torque might not be a big deal.? 5/8" bits are not a great choice for more speed and less torque.
4 pole or 6 pole motors are good for higher hz and vector duty motors are good for something like 5000-6000 rpm or up to 240 hz.? When you do that you usually oversize the motor to compensate for the loss of torque on the high end.? You also need to realize
you may have way more torque on the low end than what the machine is designed for so care must be taken.??
Thank?Brian for straightening me out on this years ago when we had a discussion here about Rong Fu mills.? Dave
After realizing that people have used end mills on their mortising attachment, I was curious if there is a way to increase the RPM of FD250. The bit on morticing attachment is likely running around 5000 RPM, whereas FD250 is around
3000 RPM.
This article says it can be done as long as motor does not exceed it’s FLA, is not electrically overloaded and operating with it’s mechanical design limits.
Anyone got an idea how much more speed might be possible?
Electrical parts can be measured but I have no clue on mechanical side of what margin might exist.
This may not result in anything meaningful but I like to learn. One thing leads to another ....
Imran
|
Re: Increasing Motor RPM via VFD
VFD rated motors can generally run up to 200hz, CNC router motors up to 400hz. Torque does drop dramatically over about 90hz.?
OK, I’ll probably start a war… but you don’t need huge rpm on router bits or on these mortisers. You can’t manually move the cutters at a rate that justifies all this rpm, all you will get is burning. Now, on a CNC router, different story, it has the capability to move the cutters at 500-1000ipm and can make use of all that rpm. I have machined mortises on my old Deckel mill and routinely done them at 1200 rpm and they come out great.?
toggle quoted message
Show quoted text
On Jan 30, 2021, at 7:54 AM, David Kumm < davekumm@...> wrote:
Given the FD is direct drive, I would think the speed is closer to 3400 in the 60 hz market.? Generally you can overspeed a 2 pole motor to about 90 hz assuming the motor is decent quality.? Downside is that torque will be reduced because you aren't maintaining the volts/hz ratio.? The benefit and need for higher speed is really for small diameter bits so the reduction in torque might not be a big deal.? 5/8" bits are not a great choice for more speed and less torque.
4 pole or 6 pole motors are good for higher hz and vector duty motors are good for something like 5000-6000 rpm or up to 240 hz.? When you do that you usually oversize the motor to compensate for the loss of torque on the high end.? You also need to realize you may have way more torque on the low end than what the machine is designed for so care must be taken.??
Thank?Brian for straightening me out on this years ago when we had a discussion here about Rong Fu mills.? Dave
After realizing that people have used end mills on their mortising attachment, I was curious if there is a way to increase the RPM of FD250. The bit on morticing attachment is likely running around 5000 RPM, whereas FD250 is around 3000 RPM.
This article says it can be done as long as motor does not exceed it’s FLA, is not electrically overloaded and operating with it’s mechanical design limits.
Anyone got an idea how much more speed might be possible?
Electrical parts can be measured but I have no clue on mechanical side of what margin might exist.
This may not result in anything meaningful but I like to learn. One thing leads to another ....
Imran
|
Jason Holtz
imran