Brushed Crystalyte 409 Problem

[Eric G]

Hello...

I've got a Crystalyte brushed rear hub motor (600 watt) with 25 amp controller running 36 volts sla in a 20 inch wheel folding bike.It's served me very well up until now with 7000 kilometers on the odometer.

The other week while riding I've noticed when I apply throttle it stutters and growls as I speed up.The stuttering and growling disappear as I approach full speed of 32km/hr.If I get off the bike and lift the back wheel and give throttle with no load it ramps up to full speed perfectly with no growling or stuttering what so ever.

The bearings are fine,with no grinding noise.When I hook up my watts up meter between the batteries and controller raised the back wheel applied full throttle,it reads .7 amps which I think is okay.I disconnected the motor attached the motor leads to a voltmeter and it measured 2 to 4 volts spinning the wheel,I don't think any windings are shorted.

I've also disconnected the motor from the controller and hooked up the voltmeter to the controller out side and it measures 0 to 39 volts as I turn the throttle so the controller and throttle seem okay.

I've triple checked all my connections and all seems fine.

Could this be the brushes starting to fail?If it is why does it run perfectly when I'm up to speed,would it not growl and stutter all along or get worse as I speed up?

Perhaps I've forgotten something else to check.This ride is my sole means of transportation and it's important that I get it sorted.Some guidance with this would be greatly appreciated.

Thanks
Eric G

 

[dogman dan]

It could be brushes with that many miles on it. Perhaps a tad early, but definitely very possible.

The other likely culprit is just a poor connection at a connector to the motor. Enough power flows for low speed, or low load, but not enough for full grunt. Could be a nicked wire at the hub, so only a few strands still connect.

And of course, it could be controller related. Controller cutting out from low battery voltage? or just a part inside finally dying.

I'd look at the wiring, then open the motor and check out the brushes. super likely it's the brushes.

 

[micart671]

Hi, I repair eBikes and had a customers bike doing very similar things.
I took the motor apart and cleaned the commutator where the brushes rest and stretched the spring on the brushes slightly to put a little more pressure on the commutator.
Put it back together and smooth as a whistle.
Now to sort out the cut out problem seeming to come from the controller.

Hope this helps

 

[dogman dan]

Perhaps a bad connection inside the controller? Like a solder joint where the wires attach to the board?

You could have broken strands at the hub exit, even if the insulation is still there.

Brush issues have a way of coming and going, as gunk scraped off the brushes from time to time. Same intermittent thing can be possible with flaky connections anywhere.

Since it's your only transportation, spares are a good idea. Spare set of brushes, spare controller, spare charger, new plugs on hand for when they might be needed, etc.

 

[Eric G]

Thank-You for the replies Dogman & micart671,my apologies for not reposting sooner!
I've double and triple checked all the connections from the battery to the motor,the batteries are fine,only 3 months.old.Soooo... it looks like I'll have to open the cover up on the darned motor.I was truly hoping I wouldn't have to.

Any tips on taking apart a c-lyte brushed hub???

Can I tackle this with just removing the side cover where the wires come out?I do have a 4 inch gear puller but it doesn't quite reach the spoke flanges of the motor to get a grip to push the innards out,if that makes any sense.

First things first though,I'll have to make a wooden type of bike holder to hold the bike upright to remove the motor wheel as my work space is only 3.5.ft. x 5.5ft. (the bottom of a flight of stairs of a tiny apartment).



Thanks again!
Eric

 

[Eric G]

I went out and bought me a 6 inch gear puller and the motor came apart with ease.
Well...it turns out is was the brushes.They were terriblely worn out,down to the copper braid that attaches to the carbon brush.It actually wore a groove in the commutator.What's really weird is this motor didn't even give a hint of trouble before the other week,I've never over volted it and am quite surprised there were no brushes left!Then again I've been using it daily since 1997 and 7000km's.

I cleaned the commutator plate as best I could installed some new brushes and am trying to get things back together.I'm having trouble with the bearing on the wire in side,it doesn't want to seat itself to where it was before,do I whack it with a hammer or ?

If someone could help me with seating the darn bearing I'd be grateful!

Hopefully I'll get a few more miles out of this ride.

It looks like I'll be moving up to a "brushless" motor now,a C-lyte-HS3548 or a 9 Continent-2805 in a 20 inch wheel but that's a topic for another thread.

Thanks Again
Eric G

 

[dogman dan]

We'll need a good well focused picture to know what your problem with the bearing is. It could just need replacement, but you should be able to tell that easily if it ginds and won't spin freely.

Hammer whacks on the cover can damage the bearing, by sliding it onto the axle crooked. A piece of 2" pipe can fit over the axle and allow a few light taps that seat the bearing straight.

You might be able to arrange your puller, to pull the cover back onto the motor, if the jaws are long enough. Or get 3-4 longer bolts, and use the bolts to pull the cover down to where the stock bolts can pull the cover down straight.

Another trick that can work, a spare tire allows the motor to be placed with the axle through the hole in the rim, then you can start gently pushing on the whole wheel as straight as possible to slide that bearing onto the axle.

Bit of lube on the axle should help too of course.

 

[Eric G]

Eureka !!!
Thanks Mr.Dogman!!!

The bearings were fine they ran smooth as silk,the issue was sliding the bearing over the axle where it's supposed to sit and sitting flush in the cup on the side cover.It sure was a tight squeeze.

I used a socket from a socket wrench set to sit over the outer race of the bearing and was able to seat it into the side cover bearing receptacle with a good few wacks of a hammer on the socket over the bearing til it sat flush in the side cover cup.Then slid the side cover over the axle,took a length (maybe 5 inches) of 2 inch diameter steel pipe,slipped that over the axle and hit the other end with a hammer til the I could set the 6 allen screws into the motor through the side cover, then just tightened it all up.Man them bearings are a real tight fit.Oh I also lubed up the axle and bearing with some synthetic grease I had kicking about.

I connected a 12 volt sla battery to the motor leads directly and ran it for about 30 minutes to set the new brushes.

Well now I gotta figure out which brushless motor and controller I'll be needing for my particular situation.I'll be starting a new thread on that topic.

Thanks

Happy Days Are Here Again...

Eric