Hi. How do I test a Emmo,ect.,ect. 500w hub motor without a working controller. I installed 4 new 12v-12ah batterys in & drove up a 1/2k mild hill. It quit. When I got home I noticed the 3 wires to the motor had melted together. I cleaned the ends, twisted & covered them and now No power to the rear wheel ? I've got 4 different volt,ohm,amp meters. I fix plenty of common 2-wire (Pos.+. & Neg.-) leads used in engine starter & pwr'd wheelchair motors. I'm going to replace the installed "Puny , It's abt. the size of a deck of cards" controller ! But ! I want to check the motor First ! These 3-wire blue,green yellow brushless motors are New to me ! Thx.
How do I test 500W Hubmotor without A working ctlr?
- Thread starter DunRite
- Start date
First, if the wires got so hot they actually melted together *outside* the motor, the motor itself probably got much hotter than that inside.
Before opening it to fix damage in there, you can test for shorted phases by flipping the bike upside down, and trying to manually turn the wheel, with the phase wires not plugged into anything. If the wheel turns easily and smoothly, then the wires inside are probably at least not touching each other, and the windings are not burned enough to short out.
If the wheel is hard to turn or "sticks" from position to position as it rotates, then one or more of the phase wires or windings is shorted to another. If it's the phase wires, you just replace those. If it's the windings, you replace the motor (it's too much of a PITA to unwind and rewind one, especially if you've never done it, and small hubmotors are relatively cheap).
Unfortunately teh controller is probably blown; FETs are probably damaged from teh shorted windings. So you will probably have to replace that. (replacing just the FETs doesn't usually fix it, often the gate drivers and other components are also damaged, sometimes in a way that's not obvious until the system is under load again, and then something dies (gate sticks on, FETs get blown, etc). )
The most likely cause is that going up the hill takes the full power of the system, and probably even at that was a slower speed than normal, so the motor overheated. At a guess, you'll need a bigger motor (and possibly controller and batteries) for that hill, to get up it at the speed necessary to keep from lugging the motor down and overheating it.
It may take some reading of it's instructions, and playing around with different setups, but you can use the http://ebikes.ca/simulator to see why it happens on a hill when it doesn't on the flats.
Before opening it to fix damage in there, you can test for shorted phases by flipping the bike upside down, and trying to manually turn the wheel, with the phase wires not plugged into anything. If the wheel turns easily and smoothly, then the wires inside are probably at least not touching each other, and the windings are not burned enough to short out.
If the wheel is hard to turn or "sticks" from position to position as it rotates, then one or more of the phase wires or windings is shorted to another. If it's the phase wires, you just replace those. If it's the windings, you replace the motor (it's too much of a PITA to unwind and rewind one, especially if you've never done it, and small hubmotors are relatively cheap).
Unfortunately teh controller is probably blown; FETs are probably damaged from teh shorted windings. So you will probably have to replace that. (replacing just the FETs doesn't usually fix it, often the gate drivers and other components are also damaged, sometimes in a way that's not obvious until the system is under load again, and then something dies (gate sticks on, FETs get blown, etc). )
The most likely cause is that going up the hill takes the full power of the system, and probably even at that was a slower speed than normal, so the motor overheated. At a guess, you'll need a bigger motor (and possibly controller and batteries) for that hill, to get up it at the speed necessary to keep from lugging the motor down and overheating it.
It may take some reading of it's instructions, and playing around with different setups, but you can use the http://ebikes.ca/simulator to see why it happens on a hill when it doesn't on the flats.
Similar threads
