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Re: Sewing Machine Motor w/foot pedal?
Modern polyurethane belts give loads of grip (get a set from Doug Feistamel), so you don't need toothed belts.The desire for toothed belts comes from one of the older books where the author goes to great lengths to make his own toothed pulleys. The complication and resulting noisy drive are just not worth it.
Yes, it is still a good idea to keep the stepped pulleys. Using the pulleys to reduce the speed range gives you higher torque at lower speeds, which is usually a good thing - theoretically ideal. It also allows much finer control at lower speeds. I found I rarely used the speed controller. Changing speeds with the belts was all I needed for most jobs especially with the extra low speed pulley. On my Unimat 3, which only has four speeds on the belts, I may use the speed controller more, but I may also make some more pulleys for more flexibility. I think it is possible to build a back gear into the large pulley, but it will not be simple. I suggest that when you change the motor, you do not change anything else until you have got used to the lathe again. Then see what might help. |
Re: Sewing Machine Motor w/foot pedal?
Jeff,
I noticed your White Buna N belt. In thinking about the belt, I wonder how well a toothed belt and corresponding pulley would work? Is there a good reason why stepped pulleys would still be needed if speed is now controlled electronically? Just wondering as I don¡¯t have experience with these motors and controllers yet. Still waiting for my components to arrive. Dick -- http://www.homemadetools.net/ ?SMALL TURRET TOOL POST PLANS? ?LARGE TURRET TOOL POST PLANS ?MINI- ?SMALL QC TOOL POST PLANS? ?QUICK CHANGE LATHE TURRET ?MINI LATHE COMPOUND PIVOT MODIFICATION |
Re: Sewing Machine Motor w/foot pedal?
On Sat, Sep 25, 2021 at 02:43 PM, Jkle379184 wrote:
Yes, not a good idea to reverse unless completely stopped.There is a way to protect the speed controller from reversing too quickly. You feed the output through a bridge rectifier. Connect the speed controller to the AC inputs, and use the +/- outputs as usual. If you then add a reversing switch after the rectifier, it will protect the speed controller from the over-voltage that occurs when you have the motor going forwards and the switch in reverse. I don't know how to rate the rectifier - I assume at least double the supply voltage, and a peak current a bit higher than the motor rating. It should not be hard to find one with a far higher rating than needed these days. The higher voltages and currents should only happen occasionally, so the rectifier shouldn't suffer much. If you find reversing is a problem then you should modify your revering switch so it is not too easy to use? - slow yourself down a bit! |
I saw this Unimat at Maker Space today
¿ªÔÆÌåÓýI went to Maker Space in Melbourne Fl today to do some woodturning. (http://www.melbournemakerspace.org/) I saw this Unimat lathe sitting on a table. Don't know any other details yet. Looks like it has been converted to run and move with DC motors and the rails have been lengthened. |
Re: Sewing Machine Motor w/foot pedal?
You can start packing up the controller.? I bought it this morning.? I have a Machinex lathe, a compact 5 lathe, and a Taig mill, all with 90 - 125 volt dc motors.? I am sure I will use it on something.?? My Sherline lathe uses a similar control, and I find it works well with only a 2 speed belt drive.? If you have any tech data for the control, please copy it and send it along.? The mill uses collets and the compact 5 lathe has bolt on chucks, so I won't have to worry about things spinning off under dynamic braking.? The Sherline uses a screw on chuck and I have only had it try to come off once under braking when I forgot to make sure it was tight.?? I am a retired Air Force electronics tech, so I? am sure I can figure out the resistors, etc if I have good tech data.
Chuck Daldry |
Re: Sewing Machine Motor w/foot pedal?
¿ªÔÆÌåÓýHello: I would suggest a reversing switch. It is very handy to back out taps. On my big lathe I often cut on the back side in reverse. The chuck backing off is a risk, but if it is tight it should stay put. Carl. On 9/25/2021 9:43 AM, Jkle379184 via
groups.io wrote:
|
Re: Sewing Machine Motor w/foot pedal?
"On my power box I have two sockets for the motor - one direct from the 24 V, the other from the speed controller. The direct one has a forward/reverse switch, but not the speed controlled connector. Reversing the power while the motor is still spinning is a good way to blow up the speed controller."
Yes, not a good idea to reverse unless completely stopped. Also on a lathe with a threaded on chuck you have to be careful using reverse. I used the color coded wires, Red +, Black - and just added individual wire push connectors. So if needed , I could just unhook and reverse the wires to reverse the motor, Something that I have yet needed to do.
?Jeff -----Original Message-----
From: Keith S. Angus <keithsangus@...> To: Jkle379184 <jkle379184@...>; [email protected] Sent: Sat, Sep 25, 2021 5:23 am Subject: Re: [Unimat] Sewing Machine Motor w/foot pedal? On Fri, Sep 24, 2021 at 03:06 PM, Jkle379184 wrote:
?I seem to recall that the power supplies were commonly used to power LED lighting. Here is a photo of the Motor that I used, the box that I put the controls in and a crude wiring schematic. I added switch position to bypass the sped control to run full speed.The power supplies are often quoted as being suitable for LEDs, but you'd need a lot of LEDs to justify 24V at 10A! Really they are general purpose power supplies - use them for whatever you like. The speed control you are using is one of the ones I suggested for Oldtoolmaker. On my power box I have two sockets for the motor - one direct from the 24 V, the other from the speed controller. The direct one has a forward/reverse switch, but not the speed controlled connector. Reversing the power while the motor is still spinning is a good way to blow up the speed controller. >>Measured full output speed of this motor was 3431 RPM. I drilled out the pulley to 8mm and it fit the motor shaft perfectly. The higher power motors run a bit slower than the lower power ones. I got a little over 4000 rpm from my 130 W motor. Somewhere or other this is documented by the motor suppliers. As said before, I got about 6000 rpm at the chuck at the highest speed setting on the pulleys. If my motor had had the longer shaft I would have opened up the pulley. Since the shaft was too short I made an extension at 6 mm and left the pulley alone. I arranged to drive it by pins, more or less as in the original, and held it on with an M4 screw, as per the original. >>Some photos of the motor end plate mods and the "top Hat" for the mounting screw all done on the Unimat. You have the motor with the brushes at the back. This makes it easy to add the extra fixing hole to the front plate without worrying about screws getting mixed up with the wiring. Note that to modify the plain front pate it is not necessary to dismantle the motor completely - it is simpler to just take the front plate off.That way you don't have to disturb the brushes, and fight the magnets when getting the armature out, and in again. If the brushes are at the front then it needs a bit of thought how to modify it without shorting out the electrics. That's one reason why I used an adaptor plate and left the motor alone. The Unimat motor has two M5 screws at 42 mm spacing. The DC motor has three M5 holes on a 42 mm circle, so you only need to add one M5 hole to fit the DC motor to the Unimat bracket. You might get away with tapping it straight into the motor end plate, but adding this reinforcement is a good idea. I had a big BANG lock-up on my SL, and after that the motor bearings were shot. If you take the motor apart consider replacing the bearings with good quality ones (SKF, NSK, FAG, etc.) while you have the chance. At least measure them up so you know what size may be needed in future. I've forgotten what they were, but it wasn't hard to find replacements. >>Photos of the motor taken apart, easy to do, just two long screws. Put the end plate with the brushes over the armature shaft first and then put that into the stator tube when putting it back together. The modified end plate with the top hat epoxy glued in place, drilled out and test mounted to the Unimat bracket.? And the last one is the unit up and running. Notice the drive belt. Just a plain old Buna white O ring, they are cheap and work great. ?I drilled the pulley out to 8mm to fit the shaft. Then I drilled the pulley for a small set screw to fit the flat section of the armature shaft. All work was done on one of my Unimats. You could do this first and then when done replace the Unimat motor with the 24vdc motor when done. Jeff Mainly covered in comments above. If you take the motor fully apart mark the end cover positions with a dab of paint or similar. It helps to get the screws back through if the covers are properly aligned. If I was doing it again I would also file a small point on the long screws, as that would help to get them into the tapped holes in the end cover. In general, if I had this motor to work with, I would have done the job very much the same way. As it was, the motor I had was significantly different, so I did things differently. If you can get a motor like this one (regardless of power) with the brushes at the back end and with a long shaft, it will be simpler. I would still recommend the 130 W motor, as it gives a bit more space around the working area, and it goes a little faster, but these are not the most important things. I haven't seen many motors with the longer shaft. I reckon it would be worth spending some time searching for that, and the brushes at the back end, The wiring can be even simpler than shown. I think the direct power option is good, but I couldn't tell you why. My power box was more complicated as it allows for a range of possible, but unknown, other uses. The biggest problem, in my experience of such things, is finding a good size box for everything. I still favour a wooden base under the lathe with the electrics inside, but that means you have to build it, so it depends on your woodworking skills. I used a commercial equipment box, but, along with the 24 V PSU that probably cost more than the motor and speed control combined. Fortunately someone in industry owed me some money/a favour, so I didn't feel the cost! |
Re: Sewing Machine Motor w/foot pedal?
Keith,
As I have no use for my KB motor control I listed it on EBay. ? Dick http://www.homemadetools.net/ ?SMALL TURRET TOOL POST PLANS? ?LARGE TURRET TOOL POST PLANS ?MINI- ?SMALL QC TOOL POST PLANS? ?QUICK CHANGE LATHE TURRET ?MINI LATHE COMPOUND PIVOT MODIFICATION |
Re: Sewing Machine Motor w/foot pedal?
Jeff,
Thanks for posting the pictures. It helps to see and understand what you have done. Dick -- http://www.homemadetools.net/ ?SMALL TURRET TOOL POST PLANS? ?LARGE TURRET TOOL POST PLANS ?MINI- ?SMALL QC TOOL POST PLANS? ?QUICK CHANGE LATHE TURRET ?MINI LATHE COMPOUND PIVOT MODIFICATION |
Re: Sewing Machine Motor w/foot pedal?
On Fri, Sep 24, 2021 at 03:06 PM, Jkle379184 wrote:
?I seem to recall that the power supplies were commonly used to power LED lighting. Here is a photo of the Motor that I used, the box that I put the controls in and a crude wiring schematic. I added switch position to bypass the sped control to run full speed.The power supplies are often quoted as being suitable for LEDs, but you'd need a lot of LEDs to justify 24V at 10A! Really they are general purpose power supplies - use them for whatever you like. The speed control you are using is one of the ones I suggested for Oldtoolmaker. On my power box I have two sockets for the motor - one direct from the 24 V, the other from the speed controller. The direct one has a forward/reverse switch, but not the speed controlled connector. Reversing the power while the motor is still spinning is a good way to blow up the speed controller. >>Measured full output speed of this motor was 3431 RPM. I drilled out the pulley to 8mm and it fit the motor shaft perfectly. The higher power motors run a bit slower than the lower power ones. I got a little over 4000 rpm from my 130 W motor. Somewhere or other this is documented by the motor suppliers. As said before, I got about 6000 rpm at the chuck at the highest speed setting on the pulleys. If my motor had had the longer shaft I would have opened up the pulley. Since the shaft was too short I made an extension at 6 mm and left the pulley alone. I arranged to drive it by pins, more or less as in the original, and held it on with an M4 screw, as per the original. >>Some photos of the motor end plate mods and the "top Hat" for the mounting screw all done on the Unimat. You have the motor with the brushes at the back. This makes it easy to add the extra fixing hole to the front plate without worrying about screws getting mixed up with the wiring. Note that to modify the plain front pate it is not necessary to dismantle the motor completely - it is simpler to just take the front plate off.That way you don't have to disturb the brushes, and fight the magnets when getting the armature out, and in again. If the brushes are at the front then it needs a bit of thought how to modify it without shorting out the electrics. That's one reason why I used an adaptor plate and left the motor alone. The Unimat motor has two M5 screws at 42 mm spacing. The DC motor has three M5 holes on a 42 mm circle, so you only need to add one M5 hole to fit the DC motor to the Unimat bracket. You might get away with tapping it straight into the motor end plate, but adding this reinforcement is a good idea. I had a big BANG lock-up on my SL, and after that the motor bearings were shot. If you take the motor apart consider replacing the bearings with good quality ones (SKF, NSK, FAG, etc.) while you have the chance. At least measure them up so you know what size may be needed in future. I've forgotten what they were, but it wasn't hard to find replacements. >>Photos of the motor taken apart, easy to do, just two long screws. Put the end plate with the brushes over the armature shaft first and then put that into the stator tube when putting it back together. The modified end plate with the top hat epoxy glued in place, drilled out and test mounted to the Unimat bracket.? And the last one is the unit up and running. Notice the drive belt. Just a plain old Buna white O ring, they are cheap and work great. ?I drilled the pulley out to 8mm to fit the shaft. Then I drilled the pulley for a small set screw to fit the flat section of the armature shaft. All work was done on one of my Unimats. You could do this first and then when done replace the Unimat motor with the 24vdc motor when done. Jeff Mainly covered in comments above. If you take the motor fully apart mark the end cover positions with a dab of paint or similar. It helps to get the screws back through if the covers are properly aligned. If I was doing it again I would also file a small point on the long screws, as that would help to get them into the tapped holes in the end cover. In general, if I had this motor to work with, I would have done the job very much the same way. As it was, the motor I had was significantly different, so I did things differently. If you can get a motor like this one (regardless of power) with the brushes at the back end and with a long shaft, it will be simpler. I would still recommend the 130 W motor, as it gives a bit more space around the working area, and it goes a little faster, but these are not the most important things. I haven't seen many motors with the longer shaft. I reckon it would be worth spending some time searching for that, and the brushes at the back end, The wiring can be even simpler than shown. I think the direct power option is good, but I couldn't tell you why. My power box was more complicated as it allows for a range of possible, but unknown, other uses. The biggest problem, in my experience of such things, is finding a good size box for everything. I still favour a wooden base under the lathe with the electrics inside, but that means you have to build it, so it depends on your woodworking skills. I used a commercial equipment box, but, along with the 24 V PSU that probably cost more than the motor and speed control combined. Fortunately someone in industry owed me some money/a favour, so I didn't feel the cost! |
Re: Sewing Machine Motor w/foot pedal?
Photos of the motor taken apart, easy to do, just two long screws. Put the end plate with the brushes over the armature shaft first and then put that into the stator tube when putting it back together. The modified end plate with the top hat epoxy glued in place, drilled out and test mounted to the Unimat bracket.? And the last one is the unit up and running. Notice the drive belt. Just a plain old Buna white O ring, they are cheap and work great.
?I drilled the pulley out to 8mm to fit the shaft. Then I drilled the pulley for a small set screw to fit the flat section of the armature shaft. All work was done on one of my Unimats. You could do this first and then when done replace the Unimat motor with the 24vdc motor when done. Jeff -----Original Message-----
From: Jkle379184 via groups.io <jkle379184@...> To: [email protected] <[email protected]> Sent: Fri, Sep 24, 2021 10:13 am Subject: Re: [Unimat] Sewing Machine Motor w/foot pedal? Some photos of the motor end plate mods and the "top Hat" for the mounting screw all done on the Unimat.
?Jeff
-----Original Message-----
From: Jkle379184 via groups.io <jkle379184@...> To: [email protected] <[email protected]> Sent: Fri, Sep 24, 2021 10:09 am Subject: Re: [Unimat] Sewing Machine Motor w/foot pedal? Measured full output speed of this motor was 3431 RPM. I drilled out the pulley to 8mm and it fit the motor shaft perfectly.
?Jeff
-----Original Message-----
From: Jkle379184 via groups.io <jkle379184@...> To: [email protected] <[email protected]> Sent: Fri, Sep 24, 2021 10:06 am Subject: Re: [Unimat] Sewing Machine Motor w/foot pedal? ?I seem to recall that the power supplies were commonly used to power LED lighting. Here is a photo of the Motor that I used, the box that I put the controls in and a crude wiring schematic. I added switch position to bypass the sped control to run full speed.
?Jeff
?
-----Original Message-----
From: Keith S. Angus <keithsangus@...> To: OldToolmaker <old_toolmaker@...>; [email protected] Sent: Thu, Sep 23, 2021 9:33 pm Subject: Re: [Unimat] Sewing Machine Motor w/foot pedal? On Fri, Sep 24, 2021 at 01:44 AM, OldToolmaker wrote:
I bought two of the 150W 24volt dc brushed motors. The price was right.I've had a look around on Ebay, specifically for units that will be simple to use, and, ideally, stocked in the USA. For a power supply, these four listings are for exactly the same thing, from USA sellers - make your choice based on price and delivery: Ebay item numbers, power supplies: 194317117950 353572057754 324322303966 333987863579 Speed controllers look to be more difficult - they are all coming from China. One type is very basic, but will do the job, and is simple to panel mount. Three suppliers of exactly the same thing: 154528849888 261313502852 224539756477 This type are more boxed up, and might suit you better. Again, all the same and all from China 274118435129 284233062492 154366376249 At the moment I can't find my way to USA surplus sellers who may have good stuff without waiting for delivery from China. Ah, here we are - standard speed controller, USA stock: https://www.allelectronics.com/item/msc-10/10a-dc-motor-speed-control/dimmer/1.html |
Re: Sewing Machine Motor w/foot pedal?
Some photos of the motor end plate mods and the "top Hat" for the mounting screw all done on the Unimat.
?Jeff -----Original Message-----
From: Jkle379184 via groups.io <jkle379184@...> To: [email protected] <[email protected]> Sent: Fri, Sep 24, 2021 10:09 am Subject: Re: [Unimat] Sewing Machine Motor w/foot pedal? Measured full output speed of this motor was 3431 RPM. I drilled out the pulley to 8mm and it fit the motor shaft perfectly.
?Jeff
-----Original Message-----
From: Jkle379184 via groups.io <jkle379184@...> To: [email protected] <[email protected]> Sent: Fri, Sep 24, 2021 10:06 am Subject: Re: [Unimat] Sewing Machine Motor w/foot pedal? ?I seem to recall that the power supplies were commonly used to power LED lighting. Here is a photo of the Motor that I used, the box that I put the controls in and a crude wiring schematic. I added switch position to bypass the sped control to run full speed.
?Jeff
?
-----Original Message-----
From: Keith S. Angus <keithsangus@...> To: OldToolmaker <old_toolmaker@...>; [email protected] Sent: Thu, Sep 23, 2021 9:33 pm Subject: Re: [Unimat] Sewing Machine Motor w/foot pedal? On Fri, Sep 24, 2021 at 01:44 AM, OldToolmaker wrote:
I bought two of the 150W 24volt dc brushed motors. The price was right.I've had a look around on Ebay, specifically for units that will be simple to use, and, ideally, stocked in the USA. For a power supply, these four listings are for exactly the same thing, from USA sellers - make your choice based on price and delivery: Ebay item numbers, power supplies: 194317117950 353572057754 324322303966 333987863579 Speed controllers look to be more difficult - they are all coming from China. One type is very basic, but will do the job, and is simple to panel mount. Three suppliers of exactly the same thing: 154528849888 261313502852 224539756477 This type are more boxed up, and might suit you better. Again, all the same and all from China 274118435129 284233062492 154366376249 At the moment I can't find my way to USA surplus sellers who may have good stuff without waiting for delivery from China. Ah, here we are - standard speed controller, USA stock: https://www.allelectronics.com/item/msc-10/10a-dc-motor-speed-control/dimmer/1.html ![]()
24vdc end plate.jpg
![]()
End plat with Top Hat installed.jpg
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Turned down Top Hat.jpg
![]()
Turning down Top Hat.jpg
|
Re: Sewing Machine Motor w/foot pedal?
Measured full output speed of this motor was 3431 RPM. I drilled out the pulley to 8mm and it fit the motor shaft perfectly.
?Jeff -----Original Message-----
From: Jkle379184 via groups.io <jkle379184@...> To: [email protected] <[email protected]> Sent: Fri, Sep 24, 2021 10:06 am Subject: Re: [Unimat] Sewing Machine Motor w/foot pedal? ?I seem to recall that the power supplies were commonly used to power LED lighting. Here is a photo of the Motor that I used, the box that I put the controls in and a crude wiring schematic. I added switch position to bypass the sped control to run full speed.
?Jeff
?
-----Original Message-----
From: Keith S. Angus <keithsangus@...> To: OldToolmaker <old_toolmaker@...>; [email protected] Sent: Thu, Sep 23, 2021 9:33 pm Subject: Re: [Unimat] Sewing Machine Motor w/foot pedal? On Fri, Sep 24, 2021 at 01:44 AM, OldToolmaker wrote:
I bought two of the 150W 24volt dc brushed motors. The price was right.I've had a look around on Ebay, specifically for units that will be simple to use, and, ideally, stocked in the USA. For a power supply, these four listings are for exactly the same thing, from USA sellers - make your choice based on price and delivery: Ebay item numbers, power supplies: 194317117950 353572057754 324322303966 333987863579 Speed controllers look to be more difficult - they are all coming from China. One type is very basic, but will do the job, and is simple to panel mount. Three suppliers of exactly the same thing: 154528849888 261313502852 224539756477 This type are more boxed up, and might suit you better. Again, all the same and all from China 274118435129 284233062492 154366376249 At the moment I can't find my way to USA surplus sellers who may have good stuff without waiting for delivery from China. Ah, here we are - standard speed controller, USA stock: https://www.allelectronics.com/item/msc-10/10a-dc-motor-speed-control/dimmer/1.html |
Re: Sewing Machine Motor w/foot pedal?
?I seem to recall that the power supplies were commonly used to power LED lighting. Here is a photo of the Motor that I used, the box that I put the controls in and a crude wiring schematic. I added switch position to bypass the sped control to run full speed.
?Jeff ? -----Original Message-----
From: Keith S. Angus <keithsangus@...> To: OldToolmaker <old_toolmaker@...>; [email protected] Sent: Thu, Sep 23, 2021 9:33 pm Subject: Re: [Unimat] Sewing Machine Motor w/foot pedal? On Fri, Sep 24, 2021 at 01:44 AM, OldToolmaker wrote:
I bought two of the 150W 24volt dc brushed motors. The price was right.I've had a look around on Ebay, specifically for units that will be simple to use, and, ideally, stocked in the USA. For a power supply, these four listings are for exactly the same thing, from USA sellers - make your choice based on price and delivery: Ebay item numbers, power supplies: 194317117950 353572057754 324322303966 333987863579 Speed controllers look to be more difficult - they are all coming from China. One type is very basic, but will do the job, and is simple to panel mount. Three suppliers of exactly the same thing: 154528849888 261313502852 224539756477 This type are more boxed up, and might suit you better. Again, all the same and all from China 274118435129 284233062492 154366376249 At the moment I can't find my way to USA surplus sellers who may have good stuff without waiting for delivery from China. Ah, here we are - standard speed controller, USA stock: https://www.allelectronics.com/item/msc-10/10a-dc-motor-speed-control/dimmer/1.html |
Re: Sewing Machine Motor w/foot pedal?
On Fri, Sep 24, 2021 at 01:44 AM, OldToolmaker wrote:
I bought two of the 150W 24volt dc brushed motors. The price was right.I've had a look around on Ebay, specifically for units that will be simple to use, and, ideally, stocked in the USA. For a power supply, these four listings are for exactly the same thing, from USA sellers - make your choice based on price and delivery: Ebay item numbers, power supplies: 194317117950 353572057754 324322303966 333987863579 Speed controllers look to be more difficult - they are all coming from China. One type is very basic, but will do the job, and is simple to panel mount. Three suppliers of exactly the same thing: 154528849888 261313502852 224539756477 This type are more boxed up, and might suit you better. Again, all the same and all from China 274118435129 284233062492 154366376249 At the moment I can't find my way to USA surplus sellers who may have good stuff without waiting for delivery from China. Ah, here we are - standard speed controller, USA stock: https://www.allelectronics.com/item/msc-10/10a-dc-motor-speed-control/dimmer/1.html |
Re: Sewing Machine Motor w/foot pedal?
Keith,? |
Re: Sewing Machine Motor w/foot pedal?
?If you use 150w motor, a 200w power supply is more then enough. You will find that the power supplies under rated and are designed to take a brief overload without blowing.
?Jeff -----Original Message-----
From: ddmckee54@... To: OldToolmaker <old_toolmaker@...>; [email protected] Sent: Thu, Sep 23, 2021 3:40 pm Subject: Re: [Unimat] Sewing Machine Motor w/foot pedal? The type of motor, and the type of DC drive must match up, maybe not exactly match in all ratings but they should be close.? A motor with brushes requires "brushed" DC drive, and a brushless motor needs a brushless drive.? The output of the drive should closely match the motor.
The voltage of the drive should probably be less than or equal to 150% of the motor voltage.? You can run a 36 volt motor with a 24 volt drive with no problem other than you'll never get to the rated motor rpm.? You can run a 24 volt motor with a 36 volt drive, and it'll PROBABLY run for a long time.? If you do that your motor rpm will be about 150% of the rated speed which won't do the bearings any favors.? In industry we commonly overspeed motors if we have to, within reason,?but this does shorten the motor life. You'll also need to be sure the drive can handle the current draw of the motor.??If you've got an amp rating for both the motor and the drive, if the drive can output 125%-150% of the motor's amp rating you're golden.? If the drive is less that 125% of the motor's rating it might run the motor, but it wiill be struggling.? A drive with a larger rating WILL run a smaller motor.? The other way around and is not so much, something is gonna go poof. What to you do when the motor is rated in one unit and the drive is rated in another?? Then you resort to that subject that most people think they'll never use once they get out of school - math.? Motors and drives will usually be rated in either Horspower, Amps, or Watts, and these values can be converted from one to the other. Horsepower = Watts / 746 Watts = Volts * Amps (This isn't exactly true for a motor since it's not a purely resistive load, but for estimation purposes it's close enough.)?? What do you do if the drive ratings are listed in volts and amps, and your motor is rated in horsepower?? Then you convert the drive's ratings to watts by multiplying the drive volts times the drive amps to get watts.? Divide that result by 746 and you get an estimate of the drive's horspower.? Again, if the drive rating is at least 125%-150% of the motor rating then as long as we don't do anything stupid the drive should be able to run that motor for years. Don |
Re: Sewing Machine Motor w/foot pedal?
The type of motor, and the type of DC drive must match up, maybe not exactly match in all ratings but they should be close.? A motor with brushes requires "brushed" DC drive, and a brushless motor needs a brushless drive.? The output of the drive should closely match the motor.
The voltage of the drive should probably be less than or equal to 150% of the motor voltage.? You can run a 36 volt motor with a 24 volt drive with no problem other than you'll never get to the rated motor rpm.? You can run a 24 volt motor with a 36 volt drive, and it'll PROBABLY run for a long time.? If you do that your motor rpm will be about 150% of the rated speed which won't do the bearings any favors.? In industry we commonly overspeed motors if we have to, within reason,?but this does shorten the motor life. You'll also need to be sure the drive can handle the current draw of the motor.??If you've got an amp rating for both the motor and the drive, if the drive can output 125%-150% of the motor's amp rating you're golden.? If the drive is less that 125% of the motor's rating it might run the motor, but it wiill be struggling.? A drive with a larger rating WILL run a smaller motor.? The other way around and is not so much, something is gonna go poof. What to you do when the motor is rated in one unit and the drive is rated in another?? Then you resort to that subject that most people think they'll never use once they get out of school - math.? Motors and drives will usually be rated in either Horspower, Amps, or Watts, and these values can be converted from one to the other. Horsepower = Watts / 746 Watts = Volts * Amps (This isn't exactly true for a motor since it's not a purely resistive load, but for estimation purposes it's close enough.)?? What do you do if the drive ratings are listed in volts and amps, and your motor is rated in horsepower?? Then you convert the drive's ratings to watts by multiplying the drive volts times the drive amps to get watts.? Divide that result by 746 and you get an estimate of the drive's horspower.? Again, if the drive rating is at least 125%-150% of the motor rating then as long as we don't do anything stupid the drive should be able to run that motor for years. Don |