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Author Topic: The 550 Motor I Have screeches sometimes? is there something going wrong?  (Read 1345 times)

Johnn

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Hi!
Though this only happens alot when the motor is up full rev!
the pink box thing , the speed controller I think - It has a green light , and that goes off when I am at full rev for some reason? , am I not meant to go this fast or something?


http://s407.photobucket.com/albums/pp156/Johno-/?action=view&current=moter.jpg

Thanks
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Peter Fitness

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Re: The 550 Motor I Have screeches sometimes? is there something going wrong?
« Reply #1 on: December 10, 2008, 10:41:25 PM »

I'll ask the obvious question - are the prop tube and bearings well lubricated and aligned properly with the motor?

Peter.
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Shipmate60

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Re: The 550 Motor I Have screeches sometimes? is there something going wrong?
« Reply #2 on: December 10, 2008, 10:45:17 PM »

Are you sure it is the motor.
If it is 550 motors have bushes either end of the armature so a drop of general purpose oil would lubricate the bushes. NOT WD40.

Bob
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Martin [Admin]

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Re: The 550 Motor I Have screeches sometimes? is there something going wrong?
« Reply #3 on: December 11, 2008, 12:38:20 AM »

Also, it may scream out of the water only.....
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andrewh

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Re: The 550 Motor I Have screeches sometimes? is there something going wrong?
« Reply #4 on: December 11, 2008, 08:30:38 AM »

550s with their nice long armature are good for high revs - especially the 3-pole versions

I have had this screetch, too - I am pretty certain its the oilite bushings (bearings that the shaft rotates in)  and the cure is, as shipmate sez, a little drop of oil on the bushes and twiddle by hand to get it distributed.

The screetch, FWIW and in my opinion, is actually the shaft getting into a whirling resonance because of some not-understood stick/slip in the bushings.  Ball-race motors don't do it (they have their own bad habits). 

As Martin (wisely) says it may well not happen in the water - it only screams when very fast and unloaded
Lubricating the brushes nerver harms, either - use contact cleaner ideally

andrew

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sheerline

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Re: The 550 Motor I Have screeches sometimes? is there something going wrong?
« Reply #5 on: December 11, 2008, 11:26:25 PM »

As Shipmate rightly points out, NO wd40 or any of those light aerosol lubricants and if you do use it and it all gets around the commutator, your motor is on borrowed time. Avoid over lubricating the beatrings as it can work its way into the commutator and you will also end up with duff motor. Just a drip of something like motor oil on the end of a watchmakers screwdriver, allowed to run into each of the shaft bearings should do it. If the motor bushes have worn, the problem may re-occur since the shaft will be thrashing around in the hole rather than simply rotating in it and at high rpm, you only need a little slop for this problem to become evident.
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