[EVDL] Motor arm shorted?

I have a small 500 watt dirt-bike for the kids that we decided to upgrade. Originally it had a 36v 35amp controller. We took out the batteries and replaced them with 4 Hawker Genesis 13ah batts. Changed the controller to a 48v 125/100amp. According to my son, the change in power was incredible. For about 20 minutes.

My other son could see the smoke coming from the motor, as he was trailing further and further behind on the stock bike.

Post mortem showed HALF of the tiny chinese motor completely smoked. I gotta get a pic up. Smoke of the arm windings are burnt apart. Two days later, my garage still stinks.

So I scored a small honeywell motor on Ebay. 13.5v 33a cont 1900rpm. It is physically at least 3 times the size of the original.

BUT, when I put 8v to it, it had a clicking noise, to me it sounded like it may have been a lifted comm bar.
It also has a small dead spot, where if it is stopped at that point it won't restart with out a nudge. Then it takes off and clicks along nicely.
The ammeter has a pulse. (This, I'm thinking, is a sure sign of a shorted comm segment)

I removed the brush cover and had it spinning slowly and rested my finger on the brushes, I could not detect any vibrations through the brush that would have told me without a doubt that it had a lifted comm.

So, off come the bells. I have a new motor, no wear on the brushes at all. However, two adjacent comm bars have blackened wires, with brittle insulation on them. there is also evidence of a scorch on the bar itself. Looks to me like a stalled motor on it's original installation smoked it and it was immediately replaced, then sold on Ebay. (I don't beleive the Ebay seller intended any malice, nor did she know what condition the motor was truely in. It does run after all)

So out comes the ohmmeter.... 1 ohm between all comm segments. Open from comm to *any steel point*.

I'll get some pics to you later.

Thanks for the help Jim!!

You got any "Mighty Tim's" laying around??
I might continue to mess with my Honeywell, but since I need to greatly modify the motor mount position anyway I may as well put on a monster motor.



--
Stay Charged!
Hump
I-5, Blossvale NY




>
> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On
> Behalf Of Jim Husted
> Sent: Thursday, September 27, 2007 9:25 PM
> To: Electric Vehicle Discussion List
> Subject: Re: [EVDL] Motor arm shorted?
>
>

> --- Tim Humphrey <[email protected]> wrote:
>
>> Just want to verify....
>> Armature is on the bench. I should NOT have a short
>> between adjacent comm segments, correct?
>
> Hey Tim
>
> On an ohm meter, yes you will. You'll need a growler
> to test for shorts between armature windings. A short
> is a hard thing to miss though as there is a dark or
> burnt winding somewhere. Plus when attempted to run
> it'll shudder and not really run. Anyway what's the
> word, what you cooking over there? The post doesn't
> state many facts or insight, what kind of motor you
> got?
>
> BTW, with an ohm meter you don't want conductivity
> between any copper to any metal, same applies to the
> field housing.
>
> Hope this helps.
>
> Cya
> Jim Husted
> Hi-Torque Electric
>
>
>
>
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Hey Tim

Sounds like you have an open winding and or a shorted
winding combo. Wayland has gotton me a few of these
little Crown PM motors that are a little smaller than
the Mighty Tim motor I did, plus they are more of a
sipper that a current chugger. I actually found
another Mighty Tim type core if you're wanting those
batts drained super fast, LMAO.

Take me some pics of the bike so I can get a feel for
what you'll need. I can also send you a pic of the
Crown PM motors to see if you feel it'll drop in and
work for you. FWIW I set one of these up on a
mobility cart axle with a 10 to 1 ratio and it's
working really good (Halloween props project). Most
of these need just a turn, bearings and brushes
(although I've yet to buy a set of brushes for them,
so don't know what a set would cost). As something
that needs to be kept under budget I could pick you
out one that may have some brush life left and turn
the comm and send it out for trial. If she works for
you then Crown dealers are EVerywhere and you could
order a set yourself if and when needed as an option.

Anyway get me some pics and I'll do them same.

Hope this helps
Cya
Jim Husted
Hi-Torque Electric

--- Tim Humphrey <[email protected]> wrote:

>
> I have a small 500 watt dirt-bike for the kids that
> we decided to upgrade.



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