Possibly burned motor question?

[lbz5mc12]

Yesterday on the way to the store going uphill against the wind I think my motor burned out. It's a 24V 250W currie motor. At first I thought it was the battery or controller. I recently switched out the currie controller and throttle for a 24-60V scooter controller and throttle. I was using a 36V controller and throttle with a 36V BMS battery pack. So I hooked up the currie controller again and I got a green light on the throttle indicator so I turned the throttle. The motor engaged for a couple of seconds then it sounded kind of rough, the light on the throttle went to red flickered and went out and then It smelled like something was burning. I determined that the smell was coming from the motor. I have a spare 36V motor of the same type so I hooked it up to the universal controller and it worked fine. Then I tried out the currie controller, the green light came on on the throttle but the motor wouldn't engage. So I think that somehow when the 24V motor died it took the 36V currie controller with it. I also hooked everything up to a different battery pack and had the same results all around so at least my BMS battery didn't get fragged. Another problem is that a can't seem to get the nut loose that holds the gear on the motor so that I can have a looksy inside to determine what happened.

 

[parajared]

When you overheat an e-bike motor there are two things that like to break the most. Most commonly the little hall sensor wires melt and break off. Easy fix for this is to go with a sensorless controller. Moderate fix is to go on digikey, order some new hall sensors and re-install, re-do all the wires.

The second most common thing that happens is your phase wires (the three fat wires that come out of your motor) fry. They like to melt the insulation off and arc together or come loose from the solder point inside the motor. The fix for this is as easy as popping the cover off your motor, de-soldering the phase wires, and soldering some new ones on. I have done this twice now, it's actually really easy and you can get get a soldering iron for around $15.

Getting the motor open may be a whole different problem however. I have to just trash a motor once because there was no way to get it open and service the stuff I broke.

 

[lbz5mc12]

The motor is a sensorless currie motor, basically a scooter motor with only a +- power connection. All of the wires that are visible are intact. I'm having a local guy I know look the motor, controller and throttle over. I think what killed it is that I hooked it up to a universal 24-60V scooter controller. The currie controllers have a limiting feature which keeps too much current from flowing into the motor and the other controller doesn't. I can't remember if he said he thinks the resistors or the transistors got fried because of not having a current limit. I killed the currie controller by hooking it up to the motor not knowing that the motor was shot and the motor pulled too much power through the currie controller possibly popping the caps. So basically it turned into a really expensive trip to the grocery store.

 

[amberwolf]

The motor is a sensorless currie motor, basically a scooter motor with only a +- power connection.

That's actually not "sensorless", but "brushed". True, it doesnt' have hall position sensors, but "sensorless" only normally refers to brushless motors.

I think what killed it is that I hooked it up to a universal 24-60V scooter controller. The currie controllers have a limiting feature which keeps too much current from flowing into the motor and the other controller doesn't.

It probably does, but given the voltage range it probably has a much higher current limit than the old currie brushed controller.

I can't remember if he said he thinks the resistors or the transistors got fried because of not having a current limit.

Probably the FETs. But gate resistors often get fried when FETs die:
http://electricle.blogspot.com/2009/12/blown-mosfets-due-to-chain-jam-possible.html

I killed the currie controller by hooking it up to the motor not knowing that the motor was shot and the motor pulled too much power through the currie controller possibly popping the caps.

Pulling too much power would rarely pop caps, unless it overheated the controller so badly taht it actually boiled the electrolyte in the caps. Usually if the caps pop, it's because they were already defective (bad electrolyte), or old, or they are hooked up to battery reverse-polarity. It's possible with insufficient capacitance that it could also overheat caps, especially as they age, because they have such high ripple current that they heat up from internal resistance--I have seen one explode from that. :lol:

It's more likely to pop the FETs from overcurrent...but if the currie controller had a current limit, it should've shut down or lowered the PWM if the mtoor was pulling too much power.

 

[lbz5mc12]

What's kind of strange is that the currie controller didn't completely die because the battery indicator on the throttle still lights up. When I twist the throttle nothing happens though.

These are the specs on the controller I'm currently using:
Rated Voltage
24 to 60 Volts
Rated Current
30 - 100 +/- 1.0 Amps
Rated Motor
Up to 1000 Watts
Conversion Efficency
95%
Under Voltage Protection
NONE
Speed Control
Hall Effect Throttle
(1 - 4 Volts) Included with controller.
Dimensions
105mm x 115mm x 48mm (L x W x H)

Here's a picture of the controller. I copied it from tncscooters.com so it's in gif format. I'm a little worried about it damaging the battery because it doesn't have low voltage protection but I'm hoping the battery's bms will take care of that.

 

[amberwolf]

What's kind of strange is that the currie controller didn't completely die because the battery indicator on the throttle still lights up. When I twist the throttle nothing happens though.

Almost certainly doesn't have anything to do with the controller, just that it is passing the pack voltage thru a fourth wire in the throttle cable. Its a very common wiring configuration; you'll see it discussed in a lot of controller repair, throttle question, and bike build threads.