Somtimes My Clutch Motor Runs Backwards And Sometimes Forwards. Why?

[LoveToLearn]

IThe motor is a consew clutch motor. It says High Power, LB 21236, 1725 rpm, 1/3 hp, model: cap-ds1, made in japan.

I just bought this machine and the lady said sometimes when you turn it on the motor will run in reverse. So she shuts it off and turns it back on until it runs normal forward. Once its running forward it stays like that until you turn it off. When you turn it back on it may run forward or backward. You wont know until you try to sew.

What could be causing this? Have any of you ever heard of this before?

There is NO REVERSE on the machine. It is the motor itself that is sometimes running in reverse and sometimes forward.

Its pure madness.

Please advise.

thanks

LoveToLearn

[Wizcrafts]

The motor is defective. Something has messed up the polarity of the pole pieces. Replace it.

[TinkerTailor]

Likely the hard parts of the motor are fine, and there is a problem with a switch or the start capacitor. It may be fixable easily by an alternator/generator/motor repair guy.

Read the second post of this thread for some info about whats going on:

http://www.eng-tips.com/viewthread.cfm?qid=338598

[dikman]

My first thought would be to replace the capacitor (the designation suggests it's a cap start?).

[mikekratz]

When I'm not playing with leather I work full time as a sailmaker. In our loft we have a ton of really old machines and cluch motors. i know exactly what your talking about. to make it go straight again..... turn the motor off, start running the hand wheel as fast as you can twards you. turn the motor back on and it will come back to reality. I've had a machine here at the loft thats one that just hasnt been replaced yet and I've been doing this for over 7 years to it.

-Mike

[TinkerTailor]

A motor has magnets that get pulled/pushed by the magnetic field of the coil. If this magnetic field stayed the same, the magnets would attract to the closest point and stay there, stopping motion. By switching the polarity of the coil just as the motor gets to this stop point, it now repels to the next magnet which is the pulling one. This makes sure the next magnet in the direction of motion is always pulling the coil, and not pushing it. The constant switching of the poles creates this motion. This happens at 60 times a second with standard ac power and motors. Polarity switching is what makes it AC, alternating current as opposed to DC, direct current

The one hick up is if the motor is powered down, and the coil starts with the opposite polarity it stopped with, it will go the opposite direction. Motors have a circuit that senses the motor position, and applies the correct polarity to the motor to turn the right way. It is completely random which state the polarity of AC power will be at the moment you start the motor, as it changes 60 times a second. If it is positive, motor goes one way, negative, it will go the other. This is what is broken in your motor.

Sometimes it is inside the start cap, as an additional circuit to the start cap, sometimes it is somewhere else in the motor. Alot of times it is fixable.

However, clutch motors have absolutely no resale value beyond scrap right now, so picking up a used one should be cheap. I know of 2 awesome motors local to me i could get for under 50 bucks each. One is a nice really nice low use juki motor and table. The whole machine and table fell of a tailgate of a truck during a shop move and broke the head, bending the table, However everything but the machine, and legs is still almost new. The other is a consew on craigslist for 25 bucks, may come with table. Also is a closing boat top shop so they may have other stuff you could get thrown in. They did sell a couple juki/consew flatbed walking foot machines for the 300-500 range a few months ago.

[electrathon]

I agree with those above, the cap start is now working correctly. This is a great time to convert to a servo motor.

[Art]

Your motor probably has a bad start capacitor, not worth fixing, get new motor.

Now please understand that Chinese mainland motors are crap. There is no other way to put it. The dealers here in the states (most are at the top of the page) warrantee them and the quality is not a problem other than one of convenience. US motors are great, German motors are great, Japanese Motors are Great, Taiwanese Motors are pretty darned good, and mainland Chinese motors are good also....while they work. The cost differences pretty much follow that progression also. I haven't seen a Chinese motor catch fire yet, but I have seen them just start running at full speed, only way to stop it was to unplug it. Most cases are it's dead, it's done, stick a fork in it. The basics seem to be there, but the electronics, not so much. But you are getting a motor for $130 or so, and if the dealer stands behind it, then you are good to go.

Art

[LoveToLearn]

A motor has magnets that get pulled/pushed by the magnetic field of the coil. If this magnetic field stayed the same, the magnets would attract to the closest point and stay there, stopping motion. By switching the polarity of the coil just as the motor gets to this stop point, it now repels to the next magnet which is the pulling one. This makes sure the next magnet in the direction of motion is always pulling the coil, and not pushing it. The constant switching of the poles creates this motion. This happens at 60 times a second with standard ac power and motors. Polarity switching is what makes it AC, alternating current as opposed to DC, direct current

The one hick up is if the motor is powered down, and the coil starts with the opposite polarity it stopped with, it will go the opposite direction. Motors have a circuit that senses the motor position, and applies the correct polarity to the motor to turn the right way. It is completely random which state the polarity of AC power will be at the moment you start the motor, as it changes 60 times a second. If it is positive, motor goes one way, negative, it will go the other. This is what is broken in your motor.

Sometimes it is inside the start cap, as an additional circuit to the start cap, sometimes it is somewhere else in the motor. Alot of times it is fixable.

However, clutch motors have absolutely no resale value beyond scrap right now, so picking up a used one should be cheap. I know of 2 awesome motors local to me i could get for under 50 bucks each. One is a nice really nice low use juki motor and table. The whole machine and table fell of a tailgate of a truck during a shop move and broke the head, bending the table, However everything but the machine, and legs is still almost new. The other is a consew on craigslist for 25 bucks, may come with table. Also is a closing boat top shop so they may have other stuff you could get thrown in. They did sell a couple juki/consew flatbed walking foot machines for the 300-500 range a few months ago.

sounds great but Im in Florida. When you come here to escape the cold this winter just bring the parts with you. Simple.

Today I went to turn the motor on and it wouldnt come on at all so I took the cover off and looked at the wires. I noticed that the nut on the black wire from the cord had fallen off and the wire itself had also come off the post. So I decided to put a new cord on since it was an ungrounded cord and I like things to be grounded. So I put the new cord on make sure the connections are good. I looked at the capacitor with a suspicious eye but could not see anything obviously wrong with it. I dont know how to test them and the lady I just bought this from said that the cap was changed and the brushes were replaced. I dont actuallly know when that happened. It may have been a year ago. The cap says, made in china. Maybe I should get a cap and put it on. Seems very simple. How much are they?

So got it all back together and everything works fine again, except it randomly starts in reverse more than half the time it seems. I tried the trick where before you start it you spin the handwheel in the proper direction and then star t it. That worked, or appeared to, until it didnt. So I think it might be the cap.

Sure I would love a servo motor but the $$$ I just spent $400 on this machine,111w-155, table, motor, light, attachments, knee raise, bobbin winder, spool holder, this whole set up and it was local. I had been looking a long time for this.

It seems the clutch is a bit chatterey. Do the clutches need to be replaced like in a car? or are they cone type like on a coaster brake on a bike? There is fast and off. That's it . No middle ground. If you feather it you can get it to go but no torque or power unless you completely let the clutch out.. I can kinda tap it to get a few stitches then tap it again and like that but there has to be a better way. Still great men and women sewed great car upholstery with clutch motors so Ill assume the problem must be me.

Would bigger pulleys on the handwheel and tiny pulley on the motor give me a lot more control? Or would it just slow down the top speed?

I have a nice 2 hp treadmill motor that I have been saving. I put one on my drill press with the controller that came with it and its really nice but I don't know how I would adapt that. It would be cool if I could use the treadmill motor and have a switch with like 5 speeds on it. Super slow, Slow, medium, fast and insane. Then have some kind of foot control where I can toggle it on or off. I just don't know how to make controls like that. Maybe could be done with just 5 different strength resistors and a 5 position switch. Then a rectifier to convert ac to dc and the foot toggle switch.

Clutch motor? I don't know any more.

Servo motor? Ill have to look into it.. Good ones are $$$$ and do they even include the controller? or does it just bolt on and use the existing clutch linkage?

Bigger handwheel with knob on it for going slow and leave the motor on for all out long straight runs.?

Treadle table? Take the motor off and be happy with 300 stitiches per minute and enjoy the health and fitness benefits. Then I can use the sewing machine to alter my right pants leg since it will become much bigger than my left from working the treadle.

Thats about it for options.

[TinkerTailor]

Most of the advertisers on the top of the page sell servo motor kits for any industrial machine, for not to much money. Look into a speed reducer as well. It can really help with the punch. Lots of threads on here about converting a machine to servo motor. $400 is not out of range for a good working machine and table, specially when you didn't have to deal with shipping.. Most users on here, save for a few old school clutch cowboys use a servo motor with a speed reducer or a swapped pulley set.

Btw, You can alternate legs on the treadle to avoid custom pants patterns.

Edited February 19, 2016 by TinkerTailor

[Wizcrafts]

1/2 hp clutch motors can be bought for under $100 and excellent servos for under $150. If you change to a new clutch motor you can either keep your existing motor pulley and belt, or buy a smaller pulley and belt to lower the top speed and add torque. A dealer can advise you on both options. I get my motors, thread, bobbins, needles, oil and machines from Toledo Industrial Sewing Machines. I also get some hard to find parts from Keystone Sewing.

[dikman]

Brushes? I suppose it could have, but my experience with AC motors is that they're squirrel-cage type induction motors, so no brushes (not including the small ones used in power tools etc, which usually have brushes).

The clutches usually are flat cork-faced devices, it could be that the cork and opposing face need cleaning.

The two pulleys you mention would certainly help, but to tame a clutch motor you will probably need a speed reducer too.

By the time you add up the possible fix to the motor, plus pulleys and speed reducer you'll probably find it's better value getting a servo. This will give you the best possible control, particularly for leather.

[CowboyBob]

Here's the cure for a grabbing clutchmotor.Take the 3-screws off the end of the motor that holds the clutch on & smear a teaspoon of vasoline or wheel bearing grease on the flywheel & re-install the clutch & end of chatter.

[LoveToLearn]

Here's the cure for a grabbing clutchmotor.Take the 3-screws off the end of the motor that holds the clutch on & smear a teaspoon of vasoline or wheel bearing grease on the flywheel & re-install the clutch & end of chatter.

nice. Will that make it easier to feather the speed and not so 'off or fast'?

Thanks

LoveToLearn

[CowboyBob]

Yes,it will stop the grabbing & taking off,make sure too that the belt isn't too tight.

[Northmount]

Brushes on a clutch motor? Take it back. You've been lied to and conned, either by the seller or her service technician!

Tom

[LoveToLearn]

what do these motors have in them?, just windings and stator? The man specifically said brushes. I mean they did tell me about the reverse thing but they played it off like it was rare and it happend just once or twice. They said the cap was replaced also and it does say made in china so it probably is newer. Maybe he didnt understand or maybe the tech said brushes to charge him more and actually did nothing to the motor. Now where do I put that vaseline exactly?

Thanks

LoveToLearn

[LoveToLearn]

Yes,it will stop the grabbing & taking off,make sure too that the belt isn't too tight.

Ok so loosening the belt so it slips a little will also help give more control?

So vaseline.

Slightly slipping belt.

small motor pulley

big handwheel pulley.

What is the biggest handwheel pulley available? The motor pulley looks standard.

Thanks

LoveToLearn

[CowboyBob]

No,you don't want the belt to slip,adj it so it has 1" of play,a smaller motor pulley 2" will help too.

[LoveToLearn]

Yes,it will stop the grabbing & taking off,make sure too that the belt isn't too tight.

I saw someplace that an extension can be put on the clutch arm on the motor and then the pedal is connected on the end of the now lengthened arm which supoosedly gives much more control over the clutch arm. Can anyone confirm or deny this?

Thanks

LoveToLearn

[LoveToLearn]

No,you don't want the belt to slip,adj it so it has 1" of play,a smaller motor pulley 2" will help too.

Ok will do Cowboy. Are bigger handwheel pulleys available also? Right now the pulleys look about equal in size. If I had a 2" motor pulley and 6" handwheel pulley thats 3:1 so my 1750 motor would be turning the machine at 583. I wonder how many stitches per minute that is.

Is this doable? I thought about a speed reducer by they are a bit pricey and it looks like you have to move the motor mounts or the sewing machine so it is offset so the reducer pulley lines up with the handwheel pulley. Not sure I want to remount the motor an inch over. I cant see how else that would work.

Thanks

LoveToLearn

[dikman]

It shouldn't be too hard to find a suitable pulley, just find a place that sells pulleys and ask for one with the diameter you want, with the correct profile for your v-belt and the correct shaft diameter (which I'd say is 1/2"). You'll need one with locking screws/bolts.

[CowboyBob]

I'm not saying this because I sell them BUT a servo is the best way to go.When you use a clutchmotor you have to learn to pump the pedal,meaning once the machine starts sewing you need to leave up or else it'll take off,a servo runs a lot like a home machine when you press on the pedal & starts off slower & doesn't get away from you.

[LoveToLearn]

I took the cover off the back of the motor and removed the capacitor. I put a voltmeter across the terminals with the meter set at 600v ac and got no reading. Then I started the motor with no capacitor and it ran the same as it did before. So the capacitor was doing nothing. I think I need a new cap to tell the motor which way to start. I dont even know if the cap that was in there is the proper cap. I wish I could get some part numbers for the cap and the wearable clutch parts. I would have a good motor then. Then I need a small motor pulley which is 15mm bore and about 35 to 45 mm diameter 3V and a speed reducter which I will make. I have been wondering why guys with the servo motors also add speed reducers? I thought the servo motor provided totall speed control.

LoveToLearn

[Art]

It does, but the speed reducer multiplies torque by 3.

Art