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Motor Spinning Backwards . Please Help!!!

Posted: Sun Nov 11, 2012 8:37 pm
by phononut
Hi There,
I am having some really frustrating problems with a "Motor Of Quality". I am fixing this motor for a friend, and when I received it one of the mainsprings was broken, as well as one of the governor springs. I fixed the mainspring and replaced the governor spring with an identical. I greased and repacked both springs and reassembled the motor. I cranked it up and it seemed to work great, and then I noticed it was running backwards! Does anyone have some insight on whats going on here. I think I may have wound the spring in backwards. It is winding fine so would the bottom spring be the only one causing the troubles? Thanks to everyone in advance for your helpful advice,

Brad :)

Re: Motor Spinning Backwards . Please Help!!!

Posted: Sun Nov 11, 2012 10:00 pm
by gramophoneshane
I've never experienced this myself, but I'm guessing that the top spring, if not both springs, must be loaded in the barrel backwards.
If the crank turns clockwise, then the racket must be installed correctly, which also means the top barrel is being rotated in the correct direction to wind up the spring.
I have a feel though, that the top spring isn't being wound up, but is being "unwound" as you crank the motor, so the spring is actually pushing the centre arbor around in the wrong direction, and winding up the bottom spring as it does so (if that makes sense).
I could be completely off track here, but it's the only way I can think of that would cause a motor to run in the wrong direction :?

I did once install the spring backwards in a single spring motor, but it didn't run.
What I did find though when I opened it up again, was that the inside end of the spring had folded over on itself, and it was trying to wind up against the curvature of the spring coils.
Unfortunately, the spring was creased where it folded over on itself, and when I tried to undo the damage, the spring broke along the crease.
If you find this is what has happened to your spring, I'd suggest heating the centre of the spring with a blowtorch before attempting to straighten it again, and I'd bend the spring back very slowly.
I haven't had the opportunity to test unfolding a spring after applying heat, but in theory it should soften the metal and help prevent the spring snapping along the crease.
Hopefully you won't have to test the theory though :)
Good luck, and let us know what you find.

I'm almost tempted to pull down a spare double spring motor & load the springs backwards just to see if I can get it to run the wrong way :D

Re: Motor Spinning Backwards . Please Help!!!

Posted: Mon Nov 12, 2012 6:24 pm
by phononut
Thanks so much Gramophoneshane
I'll have to try that out. I'll let you know what I managed to do wrong
Brad

Re: Motor Spinning Backwards . Please Help!!!

Posted: Tue Nov 13, 2012 11:30 pm
by JerryVan
Brad,

Unless I'm missing something here, it would be impossible for the motor to run backwards if it were wound clockwise, as usual. You can't store energy in the spring, (no matter how it's installed), in one direction and have it come out in the other.

Pardon me for asking but, are you absolutely certain it's running backwards? Are you viewing the shaft rotation from the correct perspective? (Sort of a "my right", "your left" kind of thing)

Re: Motor Spinning Backwards . Please Help!!!

Posted: Tue Nov 13, 2012 11:37 pm
by JerryVan
You know, the more I look at your motor, the more I believe it DOES turn backwards. Did the motor run correctly before you worked on it? I don't believe the springs are backwards however.

Re: Motor Spinning Backwards . Please Help!!!

Posted: Sat Nov 17, 2012 2:48 pm
by phononut
Hello again!
First of all thanks for the help. I disassembled the motor again and by rotating the gears every which way I found out that both springs are actually in wrong. The power form winding was the springs backing up on themselves, not coiling up but forced to uncoil. I will wind in both springs this afternoon and hopefully it will work.

Kind Regards,
Brad

Re: Motor Spinning Backwards . Please Help!!!

Posted: Mon Nov 19, 2012 6:05 pm
by Dulcetto
OK , I've done hundreds of these motors over the years . Here's my tip for working out if you have the new springs installed the right way round -- its pretty straightforward when you think of it. First thing to know is , in double spring motors of this type that have separate spring barrels for each spring , the springs are ALWAYS wound in opposing directions. OK , you know the turntable shaft has to rotate clockwise when going , so you can look at the gear train between the centre-arbor and the bottom spring barrel and easily determine which direction the spring barrel has to unwind when the motor is in operation. Then ,when you get inside the spring barrel , the outer end of the spring will need to be fitted so it is in an OPPOSING direction. For example , if the barrel unwinds clockwise in its operation , the spring will need to be fitted Anti-clockwise at its outer end. Bear in mind that sometimes the spring barrel has to be turned upsidedown to remove the access plate -- so don't get confused and put the spring in the wrong way. OK , the top spring will be fitted in the opposite direction to the bottom spring. Its really that easy !
The phenomenon of backwards running motors is caused by fitting one spring in the wrong direction and what happens is that when the centre arbor indent trys to engage with the eye-hole in the end of the spring , it pushes the end of the spring against itself and because the ends of mainsprings are de-tempered to permit drilling for eye-holes , the metal is soft and easily bends back on itself and you get the situation where the spring power turns the barrel the wrong way and thus through the gear train , the centre arbor will revolve backwards. :D