Troubleshoot

Hi

I have a magic pie 2 that was working but stopped after climbing a hill slowly. Now the motor drags as if it is on lock mode. I pulled the motor apart but note no sign of any damage (burning). I test each phase to short with wheel but no result with my meter. That ends my testing abilities. I recently purchased a new battery which seems to be okay.

How can I begin to troubleshoot my problem. What resistance should be found between each of the phases? I am running an external controller - how do i test that there is an ouptut from this device? There are three wires. I only know +ve and _ve.

Please help. I need this bike to get to work.

Regards

Allan

If you disconnect the controller, does the motor still feel locked?

If not, the controller has blown FETs and needs repair or replacement. There are a number of good threads about controller repair, though it may take some searching to find them--some are buried in "noob broken bike help" threads.

If it still feels locked even with the controller disconnected, then it's possible one or more phase wires is shorted to the stator, or to other phases. The former you can detect with the meter on continuity to the stator plates and each phase wire in turn, but the latter will basically read zero ohms or dead short on most any typical meter even on a normal undamaged motor.

nailsnglue said:

How can I begin to troubleshoot my problem. What resistance should be found between each of the phases?

Click to expand...

Step by step procedures here using a basic DMM or no meter at all.

amberwolf said:

If you disconnect the controller, does the motor still feel locked?

If not, the controller has blown FETs and needs repair or replacement. There are a number of good threads about controller repair, though it may take some searching to find them--some are buried in "noob broken bike help" threads.

If it still feels locked even with the controller disconnected, then it's possible one or more phase wires is shorted to the stator, or to other phases. The former you can detect with the meter on continuity to the stator plates and each phase wire in turn, but the latter will basically read zero ohms or dead short on most any typical meter even on a normal undamaged motor.

Click to expand...

The motor hard to turn with controller disconnected. There appears no short to the stator. I get 0.07 ohms on each wire. Next step?

New motor. It is shorted.

.07R to the stator is shorted to the stator.

dnmun said:

.07R to the stator is shorted to the stator.

Click to expand...

Make that 0.7 ohms testing each motor phase with another motor phase. 0 ohms to the stator. No short to the stator.

I tried disconnecting the controller but the motor is equally hard to turn.

How can I test the output from the controller with my meter? I can get 5 volts on the black hall wire with all other hall sensor wires. However I get no volts coming from the phases but I dont know how to measure.

Al

If the motor is hard to turn with the controller disconnected, the trouble is with the motor. Hand held meters aren't accurate enough below 1 OHM to use for seeing if they resistance is because of a short, or normal condition.

There are 3 ways the motor could have failed.
1 Bad bearings. That would make the motor hard to turn and probably noisy. The motor will likely feel stiff if you try to turn it, or may be so lose that you can wiggle the motor side to side.
2 dislocated magnet. If the motor gets hot while riding slow up a hill, the glue holding the magnets can let go and they will drop onto the stator. that will make the motor hard to turn. If the magnet survives unbroken, it can sometimes be re-glued for a full repair.
3 Shorted coils. Something rubbed, melted, or burned through in the motor and is shorting the coils together now. The only repair is to re wind the motor.

i don't think you understand the term shorted.

0 ohms to the stator is shorted.

the phase wires are in direct physical and electrical contact with the stator.

the motor is dead. it has to be rewound if you wanna use it again.

I purchased a new motor, bafang mid mount motor 500w 48 v as I couldnt seem to work out why my old magic pie went kaput. After all it had to be the motor or controller as the battery was new and only used a few times. However much to my disgust the golden motor battery stops working when befang under any kind of load. Befang only draws 500watts as opposed to magic pie 1000w. This is the second battery from golden motor that has failed like this. I always keep it charged. The voltage drop in the battery must be so bad that the magic pie couldnt not even operate hence the symptoms.

The last battery that failed showed significant voltage drop in three cells when testing under load. I'll do some troubleshooting and look at buying cells to replace the dud ones. Where is the cheapest place? In the meantime, I'd like to warn anyone about golden motor. The products fail (well at least for me) and there is absolutely no support or warranty and yet the price is so high. That is the last item I buy from golden motor.

your battery is unbalanced and you can balance it depending on what you have for tools and skills.

post up a picture of the battery when you have it open and your charger and the charger output voltage if you have a voltmeter.