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I've got the black bull 4x6 I noticed the motor says clark on it. Haven't used it much and maybe have had it a couple years. Anyway,the other day I started to cut some tubing 1/2 inch or so and made a couple cuts and all was fine.Went to cut another piece and the motor stalled out just as I started to make the cut. It wasn't the blade got bound up it was just that the motor seemed like it had very little torque. It still had power to it and was trying to rotate but just couldn't make itself go. Lifting the blade off the workpiece it resumed normal speed then lowering the blade back down as soon as it touched the work piece it stalled the motor again. I just turned it on and off a couple times and turned the motor with it off and it was all normal. Turned it back on and made a few cuts and it worked fine. I'm just wondering if anyone has any ideas what might have been going on?
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Hi James I'm no electrician but I suspect that at some time the motor has been stalled before and its 'let some of the smoke out'.? What happens when it stalls is that the current in the copper windings rises drastically and the insulating coating on the wire starts to melt, then burn.? Even melting the insulation is bad because the thickness of insulation between wires where they touch one another decreases and the insulation value between the wires and from the wires to ground decreases too. The effects are cumulative; if it burn would burn out in 30 secs, then 5 lots of 6 seconds will burn it out too, even if it appears that the motor was OK after each stall, the damage mounts up. The only way to know if that's really the case is to have an electrician Megger the windings.? They put a high voltage on the windings and measure the resistance to ground; there are accepted values for what it should be and when its failing. Might be some useful info for you in this doc,? Replacing 4x6 bandsaw motors v3.pdf???(its in the files section) Rgds - jv
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Assuming your motor cap start/Cap run type, (big lump on the side of the cylinder that is?your motor)?I would suspect that based on your description, you have a loose wire connecting to the run Cap. Without that connection your motor (if it is that type) can not generate significant torque.
I doubt it is "having? let the smoke out"-Yet.
I suspect loose wiring because it started working again.? If the cap was bad, then that more than likely would not have happened. This would be in your motor terminal compartment more than likely.
It is also possible that you just have a bad power connection, that is giving your motor reduced voltage, enough to turn unloaded, but not enough to run under load. This could be anywhere from your motor terminals, to your switch, and all the way to your plug, extension cord or wall socket.
Unplug your motor before you look at any of these areas.
im no electrician either, but I am an engineer.
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my motor has 2 of the "big lumps" and then another square box with the power cord going into it. I was wondering if it may have something to do with the caps. I always plug it in to the same group of outlets that I plug other things into so I'm doubting a problem at the output. The 'letting the smoke out" I also doubt because the saw has never ran un attended. It's actually ran very little and I'm always right there nursing it along. Often with tubing or blackpipe I control the downspeed when it gets to where it would possibly feed itself down to fast just by hand,putting a little more pressure with my fingers to prevent it from dropping too quickly and possibly binding the blade. If I continue to have the problem I'll look into the various wiring junctions. With it unplugged of course. I know some years ago I bought an electric meat smoker and it quit working in about a month and when I looked at the wiring at the heating element the female spades that went to the male spades of the element were totally gone. All that was left of them were the area where they were crimped around the wire,so that got me thinking maybe the wiring in the saw is using some pot metal type of terminals and the trip here from china get's some salty air to them and speeds up the disintegration process.
? I also was just wondering if one of the caps are just going bad. I have a little more sawing to do on a project I'm working on now,cut a threaded rod and a few cuts in some small angle iron so I'll see how that goes.
On Thursday, November 7, 2019, 5:37:31 PM EST, Jim.Klessig@... <jim.klessig@...> wrote:
Assuming your motor cap start/Cap run type, (big lump on the side of the cylinder that is?your motor)?I would suspect that based on your description, you have a loose wire connecting to the run Cap. Without that connection your motor (if it is that type) can not generate significant torque.
I doubt it is "having? let the smoke out"-Yet.
I suspect loose wiring because it started working again.? If the cap was bad, then that more than likely would not have happened. This would be in your motor terminal compartment more than likely.
It is also possible that you just have a bad power connection, that is giving your motor reduced voltage, enough to turn unloaded, but not enough to run under load. This could be anywhere from your motor terminals, to your switch, and all the way to your plug, extension cord or wall socket.
Unplug your motor before you look at any of these areas.
im no electrician either, but I am an engineer.
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Jims reply is much more likely - intermittent contact, esp if its never been stalled.?
My only experience with a bad capacitors (on 2 different motors) was that the motors ran unsteadily for a few seconds and then lots of smoke and they stopped.? Replaced capacitors and they've been good ever since - jv
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I made just a couple of cuts a couple days ago and it ran fine. I've got a couple more cuts (this time just some small angle iron an inch or so) so I'll see how that goes.
On Friday, November 8, 2019, 12:51:47 PM EST, John Vreede <vreededesign@...> wrote:
Jims reply is much more likely - intermittent contact, esp if its never been stalled.?
My only experience with a bad capacitors (on 2 different motors) was that the motors ran unsteadily for a few seconds and then lots of smoke and they stopped.? Replaced capacitors and they've been good ever since - jv
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My motor was slow to start.? When I put on a new capacitor the difference in starting speed was remarkable.? Then I left it sawing and it hung in the cut and all the smoke got out.? You're wise not to leave yours unattended.
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I'm thinking when I change out the start switch for a magnetic one I might add a movement sensor for the upper wheel.? Stops turning, turns off the power.
---
Jerry Durand
Durand Interstellar, Inc.
On Dec 29, 2019, at 17:46, hepps_29646 < orwhut@...> wrote:
My motor was slow to start.? When I put on a new capacitor the difference in starting speed was remarkable.? Then I left it sawing and it hung in the cut and all the smoke got out.? You're wise not to leave yours unattended.
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Yeah I've thought about that too Jerry.
Do you have any particular sensor in mind?
I wonder if a sensor on the motor might be better, as its the motor you're trying to protect.
If it loads up so the motor rpm drops to 1250rpm, it will stall almost immediately it drops any lower, so a sensor that cuts the power between 1300 and 1250 rpm would be ideal.? There must be an electric/electronic solution.? Anyone out there who can comment? - jv??
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I was figuring an inductive sensor reading the wheel spokes.? Simple, doesn't care about dirt/damp.
Something like one of these:
I once replaced all the optical sensors on a production line with inductive ones.? Suddenly we stopped getting service calls all the time.? When I gutted the motor controller box and reduced it to about 4 parts that solved most of the rest of the calls.
The engineer who designed the system was pissed when he saw what I did.
The production manager, however, was delighted.
---
Jerry Durand
Durand Interstellar, Inc.
Yeah I've thought about that too Jerry.
Do you have any particular sensor in mind?
I wonder if a sensor on the motor might be better, as its the motor you're trying to protect.
If it loads up so the motor rpm drops to 1250rpm, it will stall almost immediately it drops any lower, so a sensor that cuts the power between 1300 and 1250 rpm would be ideal.? There must be an electric/electronic solution.? Anyone out there who can comment? - jv??
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It will have to have a manual override switch to start it. ? ?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of Jerry Durand
Sent: Monday, December 30, 2019 01:17
To: [email protected]
Subject: Re: [4x6bandsaw] motor acted funny the other day? I was figuring an inductive sensor reading the wheel spokes.? Simple, doesn't care about dirt/damp. Something like one of these: I once replaced all the optical sensors on a production line with inductive ones.? Suddenly we stopped getting service calls all the time.? When I gutted the motor controller box and reduced it to about 4 parts that solved most of the rest of the calls. The engineer who designed the system was pissed when he saw what I did. The production manager, however, was delighted.
Durand Interstellar, Inc. On Dec 29, 2019, at 23:02, John Vreede <vreededesign@gmailcom> wrote: Yeah I've thought about that too Jerry.
Do you have any particular sensor in mind?
I wonder if a sensor on the motor might be better, as its the motor you're trying to protect.
If it loads up so the motor rpm drops to 1250rpm, it will stall almost immediately it drops any lower, so a sensor that cuts the power between 1300 and 1250 rpm would be ideal.? There must be an electric/electronic solution.? Anyone out there who can comment? - jv??
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I figure the standard green button to start, red to stop.? Green closes the relay and starts a ramp-up timeout.? After that each spoke passing is timed.? Too long, kill power.
And, of course a switch to detect the cut is done.? That kills power immidiately.
---
Jerry Durand
Durand Interstellar, Inc.
It will have to have a manual override switch to start it.
?
?
?
I was figuring an inductive sensor reading the wheel spokes.? Simple, doesn't care about dirt/damp.
Something like one of these:
I once replaced all the optical sensors on a production line with inductive ones.? Suddenly we stopped getting service calls all the time.? When I gutted the motor controller box and reduced it to about 4 parts that solved most of the rest of the calls.
The engineer who designed the system was pissed when he saw what I did.
The production manager, however, was delighted.
Durand Interstellar, Inc.
On Dec 29, 2019, at 23:02, John Vreede <vreededesign@gmailcom> wrote:
Yeah I've thought about that too Jerry.
Do you have any particular sensor in mind?
I wonder if a sensor on the motor might be better, as its the motor you're trying to protect.
If it loads up so the motor rpm drops to 1250rpm, it will stall almost immediately it drops any lower, so a sensor that cuts the power between 1300 and 1250 rpm would be ideal.? There must be an electric/electronic solution.? Anyone out there who can comment? - jv??
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What about a simple motor controller with overload protection (aka a heater)?
On Dec 30, 2019 02:42, Jerry Durand <jdurand@...> wrote: I figure the standard green button to start, red to stop.? Green closes the relay and starts a ramp-up timeout.? After that each spoke passing is timed.? Too long, kill power.
And, of course a switch to detect the cut is done.? That kills power immidiately.
---
Jerry Durand
Durand Interstellar, Inc.
On Dec 29, 2019, at 23:38, "Robert Downs via Groups.Io" < cs.com@groups.io target=_blank> [email protected]> wrote:
It will have to have a manual override switch to start it.
?
?
?
I was figuring an inductive sensor reading the wheel spokes.? Simple, doesn't care about dirt/damp.
Something like one of these:
I once replaced all the optical sensors on a production line with inductive ones.? Suddenly we stopped getting service calls all the time.? When I gutted the motor controller box and reduced it to about 4 parts that solved most of the rest of the calls.
The engineer who designed the system was pissed when he saw what I did.
The production manager, however, was delighted.
Durand Interstellar, Inc.
On Dec 29, 2019, at 23:02, John Vreede <vreededesign@gmailcom> wrote:
Yeah I've thought about that too Jerry.
Do you have any particular sensor in mind?
I wonder if a sensor on the motor might be better, as its the motor you're trying to protect.
If it loads up so the motor rpm drops to 1250rpm, it will stall almost immediately it drops any lower, so a sensor that cuts the power between 1300 and 1250 rpm would be ideal.? There must be an electric/electronic solution.? Anyone out there who can comment? - jv??
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If you're just trying to protect the motor, that
works.? I'm looking at adding the relay power switch so it doesn't
sometimes turn back on when you lift up the arm.? When you're 200
cuts into the day you're not as alert and could get hurt.
Then around the 300th cut in this job the blade popped off.? It
turns out there was a wad of plastic fluff hidden that jammed the
blade.
So I thought a wheel sensor would be good and easy to add to the
power relay I haven't built yet.
I normally make boards from scratch, but for one-off jobs like
this I will probably start using the NANO boards.? At less than $2
delivered I can't beat the price.?
The only thing I'd need to get is the debugging pod from
MicroChip, I would highly prefer to program in a real IDE and not
use the Arduino thing.
On 12/30/19 3:36 AM, Aaron Brace wrote:
What about a simple motor controller with overload
protection (aka a heater)?
--
Jerry Durand, Durand Interstellar, Inc.
tel: +1 408 356-3886
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??? ??? that could prob be done pretty with a Arduino &
someone that knows how to program it
??? ??? animal
On 12/29/2019 11:03 PM, John Vreede
wrote:
toggle quoted message
Show quoted text
Yeah I've thought about that too Jerry.
Do you have any particular sensor in mind?
I wonder if a sensor on the motor might be better, as its the
motor you're trying to protect.
If it loads up so the motor rpm drops to 1250rpm, it will stall
almost immediately it drops any lower, so a sensor that cuts the
power between 1300 and 1250 rpm would be ideal.? There must be an
electric/electronic solution.? Anyone out there who can comment? -
jv??
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I’ll comment that if the motor is a 1750 RPM nominal and ?routinely loads down to 1250 RPM, either the ?motor id/was too small, the blade pressure is too high, or something else is wrong.? Because my original motor and the replacement (after stupidly letting it run unattended) didn’t/don’t slow down much at all.? So there may be a real problem that you are trying to put a bandaid on instead of fixing. ? ?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of mike allen
Sent: Monday, December 30, 2019 11:20
To: [email protected]
Subject: Re: [4x6bandsaw] motor acted funny the other day? ??? ??? that could prob be done pretty with a Arduino & someone that knows how to program it ??? ??? animal On 12/29/2019 11:03 PM, John Vreede wrote: Yeah I've thought about that too Jerry.
Do you have any particular sensor in mind?
I wonder if a sensor on the motor might be better, as its the motor you're trying to protect.
If it loads up so the motor rpm drops to 1250rpm, it will stall almost immediately it drops any lower, so a sensor that cuts the power between 1300 and 1250 rpm would be ideal.? There must be an electric/electronic solution.? Anyone out there who can comment? - jv??
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Normally such motor protection is done by monitoring current, not speed. Current is relatively easy and cheap to monitor, speed not so much. The easiest and cheapest way would be to put in a fuse. If the cost of fuses becomes an issue, the problem is not being addressed. The protection should not be required regularly, it is just to prevent burning out the motor in the event that something goes wrong, Such as stalling the motor or over loading it to the point that it slows down.?
On Monday, December 30, 2019, 04:44:24 PM EST, Robert Downs via Groups.Io <wa5cab@...> wrote:
I’ll comment that if the motor is a 1750 RPM nominal and ?routinely loads down to 1250 RPM, either the ?motor id/was too small, the blade pressure is too high, or something else is wrong.? Because my original motor and the replacement (after stupidly letting it run unattended) didn’t/don’t slow down much at all.? So there may be a real problem that you are trying to put a bandaid on instead of fixing. ? ?
From: [email protected] [mailto:[email protected]] On Behalf Of mike allen
Sent: Monday, December 30, 2019 11:20
To: [email protected]
Subject: Re: [4x6bandsaw] motor acted funny the other day ? ??? ??? that could prob be done pretty with a Arduino & someone that knows how to program it ??? ??? animal On 12/29/2019 11:03 PM, John Vreede wrote: Yeah I've thought about that too Jerry.
Do you have any particular sensor in mind?
I wonder if a sensor on the motor might be better, as its the motor you're trying to protect.
If it loads up so the motor rpm drops to 1250rpm, it will stall almost immediately it drops any lower, so a sensor that cuts the power between 1300 and 1250 rpm would be ideal.? There must be an electric/electronic solution.? Anyone out there who can comment? - jv??
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Sound like a simple IEC (cheap) motor
starter either manual or magnetic with a properly sized adjustable motor
overload would be an easy solution.
?
While speed sensing sounds like a fun project
and I am all for neat projects, simple straight forward solution is to add a
motor overload. Oh, and did I mention this is also a recognized industrial
solution to the problem. Check our Automation Direct.
?
gary
?
?
Normally such motor protection is done by monitoring
current, not speed. Current is relatively easy and cheap to monitor, speed not
so much. The easiest and cheapest way would be to put in a fuse. If the cost of
fuses becomes an issue, the problem is not being addressed. The protection
should not be required regularly, it is just to prevent burning out the motor
in the event that something goes wrong, Such as stalling the motor or over loading
it to the point that it slows down.?
On Monday,
December 30, 2019, 04:44:24 PM EST, Robert Downs via Groups.Io
<wa5cab@...> wrote:
I’ll
comment that if the motor is a 1750 RPM nominal and ?routinely loads down
to 1250 RPM, either the ?motor id/was too small, the blade pressure is too
high, or something else is wrong.? Because my original motor and the
replacement (after stupidly letting it run unattended) didn’t/don’t slow down
much at all.? So there may be a real problem that you are trying to put a
bandaid on instead of fixing.
?
?
?
??? ??? that
could prob be done pretty with a Arduino & someone that knows how to
program it
??? ???
animal
On
12/29/2019 11:03 PM, John Vreede wrote:
toggle quoted message
Show quoted text
Yeah
I've thought about that too Jerry.
Do you have any particular sensor in mind?
I wonder if a sensor on the motor might be better, as its the motor you're
trying to protect.
If it loads up so the motor rpm drops to 1250rpm, it will stall almost
immediately it drops any lower, so a sensor that cuts the power between 1300
and 1250 rpm would be ideal.? There must be an electric/electronic
solution.? Anyone out there who can comment? - jv??
|
I was told by another member that 1250 RPM was earlier given as the speed at which the motor would suddenly stall, not the RPM at which it was being routinely loaded down to.? If that’s the case, I missed it, and everyone should just disregard my comments. ? ?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of Jack Delaney via Groups.Io
Sent: Monday, December 30, 2019 17:34
To: [email protected]
Subject: Re: [4x6bandsaw] motor acted funny the other day? Normally such motor protection is done by monitoring current, not speed. Current is relatively easy and cheap to monitor, speed not so much. The easiest and cheapest way would be to put in a fuse. If the cost of fuses becomes an issue, the problem is not being addressed. The protection should not be required regularly, it is just to prevent burning out the motor in the event that something goes wrong, Such as stalling the motor or over loading it to the point that it slows down.? On Monday, December 30, 2019, 04:44:24 PM EST, Robert Downs via Groups.Io <wa5cab@...> wrote: I’ll comment that if the motor is a 1750 RPM nominal and ?routinely loads down to 1250 RPM, either the ?motor id/was too small, the blade pressure is too high, or something else is wrong.? Because my original motor and the replacement (after stupidly letting it run unattended) didn’t/don’t slow down much at all.? So there may be a real problem that you are trying to put a bandaid on instead of fixing. ?
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Just a side note, my idea to monitor the upper
wheel will detect loose/broken blade, slipping drive belt, AND
motor stall.
A fuse monitors stall.
On 12/30/19 4:01 PM, Robert Downs via
Groups.Io wrote:
I
was told by another member that 1250 RPM was earlier given
as the speed at which the motor would suddenly stall, not
the RPM at which it was being routinely loaded down to.? If
that’s the case, I missed it, and everyone should just
disregard my comments.
?
--
Jerry Durand, Durand Interstellar, Inc.
tel: +1 408 356-3886
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John Vreede
Jerry Durand