Controller DEAD?

[420b]

New update: I should mention that the motor is a DD hall sensored hub motor. The motor spins freely when the controller is off but not when it is on. That is said to be a common symptom of a shorted FET, but I can’t seem to find any shorted FET. I checked 12 V and 5 V supply, along with hall sensors in the wheel and throttle, all of which are good. I noticed the brake wire and regen brake wire are low on voltage (1.3 V and .6 V). I tried to boost their voltage to 5 V to possibly disable electronic braking, but it didn’t fix the issue. So what do you guys think? Dead controller? Any other tests I can do to help you guys help me?


Old post: Basically I was pushing my bike really hard up a huge hill, and the bullet connectors for the hall phase power melted. I taped it up and said I’d just fix it later, but as I passed over a rough patch of dirt there was this strong resistance from my motor. Got out the digital multimeter and what do you know: it’s a short between all 3 power phase wires. At least if I unplug the battery, the resistance goes away, but is it safe to ride home on this? Also, any bets on if the motor is toasted?

 

[Hillhater]

What motor ?... I assume its a hub motor ?
What controller ?
You wont know if its fully toasted untill you strip and inspect.
How far home,.....what other options to get home ?
Make sure you disconnect the controller from the motor also.
I assume this is a academic question ,..unless you are camped at the roadside still !
But for reference , If it rolls ok, i would ride home... (you wont carry it far)

 

[420b]

What motor ?... I assume its a hub motor ?
What controller ?
You wont know if its fully toasted untill you strip and inspect.
How far home,.....what other options to get home ?
Make sure you disconnect the controller from the motor also.
I assume this is a academic question ,..unless you are camped at the roadside still !
But for reference , If it rolls ok, i would ride home... (you wont carry it far)

Sorry for the lack of details, but in fact it was a roadside post. It’s a hub motor with generic controller and 3 halls. I disconnected the wires that I could, some wouldn’t come out (melted plug). I rode it home and I’m going to take it apart when I have time.

I’m wondering why the phase power bullets melted yet the wire did not... Must mean I need an upgrade. Maybe I can use an xt60 as a single pole connector (that’s the only thing I have).

 

[Hillhater]

Melted connectors just means high resistanceat that point,..either between the connectors (corrosion, loose contacts ?) or with the cable to connector joins..(corrosion, dry solder, loose crimps, etc)
Remake the entire set using quality connectors with good crimps or soldering.
....after you fix the motor problems.

 

[Icewrench]

I suspect that your motor is ok. Continuity between all phase leads is a good thing. If 2 melted bullet connectors were to touch each other that would make the motor hard to turn and it might just damage a fet in the controller.

 

[billvon]

Basically I was pushing my bike really hard up a huge hill, and the bullet connectors for the hall phase power melted. I taped it up and said I’d just fix it later, but as I passed over a rough patch of dirt there was this strong resistance from my motor. Got out the digital multimeter and what do you know: it’s a short between all 3 power phase wires.

Just FYI it always looks like a short between all three phases. You'd need a very good milliohm meter to see any resistance at all in the phases.

 

[420b]

Thanks for the correction about the power phase wires. Now, I’m guessing the controller is toast in some way because when I connect it and power it on with the throttle button, the motor has resistance (feels like regen braking is on. Side note: is this how regen is done?). I’ve done some searching on this forum which has lead me to believe a dead MOSFET is in some way causing the power wires to behave badly (if anyone could explain this it would be extremely helpful to me. I know the thing is like a switch that allows current, though I’m not quite sure what the mosfet’s function in this particular circuit is). I’ve checked and it seems everything else is being powered correctly (hall sensor’s, throttle, etc). How would I check if the mosfets are failed, and how would I locate a failed one?

[strike][/strike]

 

[Voltron]

There's a bunch of way better explanations how to test it than I can give, but the point of the mosfets is to chop up the voltage between the battery and the motor at partial throttle, and switching between energising the phases instead of mechanical commutation like a brushed motor.
Quick motor test, if you touch two of the three phase wires coming out of the motor together, it should suddenly make the motor hard to spin by hand. Test all three combos, and if one stays easy to turn it's a shorted winding.

 

[billvon]

Now, I’m guessing the controller is toast in some way because when I connect it and power it on with the throttle button, the motor has resistance (feels like regen braking is on. Side note: is this how regen is done?).

There are several ways to do regen; one popular way is to turn on all the bottom-side FETs for a short time. This shorts the windings and causes a lot of current to build up in them. Then the bottom side FETs are opened. The current needs somewhere to go so it flows through the body diodes on the top side FETs back to the battery.

I’ve done some searching on this forum which has lead me to believe a dead MOSFET is in some way causing the power wires to behave badly (if anyone could explain this it would be extremely helpful to me. I know the thing is like a switch that allows current, though I’m not quite sure what the mosfet’s function in this particular circuit is).

MOSFETs are switches. MOSFETs most commonly fail closed (i.e. always on) which looks just like a shorted winding. If the motor spins freely when the controller is disconnected, but is hard to turn when it is connected (but the power is off) then a shorted FET is likely.

However that doesn't sound like your problem, since you say that it only causes resistance when you add throttle. That sounds a lot like a phasing problem between your Hall sensors and motor windings.
==========================

Quick motor test, if you touch two of the three phase wires coming out of the motor together, it should suddenly make the motor hard to spin by hand. Test all three combos, and if one stays easy to turn it's a shorted winding.

Well, to be more exact -

If you really have a shorted phase the motor will be harder to turn. If you externally short that one phase and the motor doesn't get any HARDER to turn, you've found the bad phase. (But it will be hard in any case.)

If you have a motor that spins freely, and you short one phase, and the motor doesn't get any harder to spin, then you have an open connection somewhere. (Usually in the motor lead going into the case.)

 

[420b]

Now, I’m guessing the controller is toast in some way because when I connect it and power it on with the throttle button, the motor has resistance (feels like regen braking is on. Side note: is this how regen is done?).

There are several ways to do regen; one popular way is to turn on all the bottom-side FETs for a short time. This shorts the windings and causes a lot of current to build up in them. Then the bottom side FETs are opened. The current needs somewhere to go so it flows through the body diodes on the top side FETs back to the battery.

I’ve done some searching on this forum which has lead me to believe a dead MOSFET is in some way causing the power wires to behave badly (if anyone could explain this it would be extremely helpful to me. I know the thing is like a switch that allows current, though I’m not quite sure what the mosfet’s function in this particular circuit is).

MOSFETs are switches. MOSFETs most commonly fail closed (i.e. always on) which looks just like a shorted winding. If the motor spins freely when the controller is disconnected, but is hard to turn when it is connected (but the power is off) then a shorted FET is likely.

However that doesn't sound like your problem, since you say that it only causes resistance when you add throttle. That sounds a lot like a phasing problem between your Hall sensors and motor windings.
==========================

Quick motor test, if you touch two of the three phase wires coming out of the motor together, it should suddenly make the motor hard to spin by hand. Test all three combos, and if one stays easy to turn it's a shorted winding.

Well, to be more exact -

If you really have a shorted phase the motor will be harder to turn. If you externally short that one phase and the motor doesn't get any HARDER to turn, you've found the bad phase. (But it will be hard in any case.)

If you have a motor that spins freely, and you short one phase, and the motor doesn't get any harder to spin, then you have an open connection somewhere. (Usually in the motor lead going into the case.)

The motor spins freely until you short the phases. So doesn’t look like a problem there. Only when the throttle button is on which makes the power go to the controller, then the motor has resistance. When I unplug one power phase and spin there is resistance for a second then it cuts out and then it’s back on. My MOSFETs are called HY1707. I checked the diode drop on each MOSFET from source to drain and drain to source, there isn’t a short and from source to drain there is a 470mV drop on all of the mosfets. Also I should note that the voltage on my brake wire to ground is actually only 1.3 V and my voltage on the regen brake wire is only .6 V which is troubling (I checked because I suspected there was a short there causing the motor not to go. Anyways shouldn’t it be 5v??). So I don’t know what to do.

 

[markz]

The walk of shame back home after you try to diagnose and fix it on the sidewalk is always a downer!

The call to have someone pick you up, is even worse.

 

[billvon]

The motor spins freely until you short the phases. So doesn’t look like a problem there. Only when the throttle button is on which makes the power go to the controller, then the motor has resistance. When I unplug one power phase and spin there is resistance for a second then it cuts out and then it’s back on. My MOSFETs are called HY1707. I checked the diode drop on each MOSFET from source to drain and drain to source, there isn’t a short and from source to drain there is a 470mV drop on all of the mosfets. Also I should note that the voltage on my brake wire to ground is actually only 1.3 V and my voltage on the regen brake wire is only .6 V which is troubling (I checked because I suspected there was a short there causing the motor not to go. Anyways shouldn’t it be 5v??). So I don’t know what to do.

OK. Well I can't figure out your problem from here but some ideas:

1) If the controller lets the wheel spin freely when the controller is connected and powered down, then it's not a shorted FET.

2) If the throttle button enables the controller (which would be odd - why not leave it on?) then I would suspect a bad brake input, thus turning regen on all the time. If the throttle button just applies the throttle, then I would suspect the Hall sensors (see below.)

3) This is concerning: "the bullet connectors for the hall phase power melted." The Hall sensor wires carry almost no current, so that indicates a catastrophic failure inside the controller (and/or inside the motor.) Did you mean "bullet connectors for phase power?"

4) In any case, if your motor does use Hall sensors, I'd start there. Verify they are getting 5V and that each one turns on and off as you rotate the wheel slowly. If they do, then try different combinations of them to see if it's a phase mismatch.

 

[420b]

The motor spins freely until you short the phases. So doesn’t look like a problem there. Only when the throttle button is on which makes the power go to the controller, then the motor has resistance. When I unplug one power phase and spin there is resistance for a second then it cuts out and then it’s back on. My MOSFETs are called HY1707. I checked the diode drop on each MOSFET from source to drain and drain to source, there isn’t a short and from source to drain there is a 470mV drop on all of the mosfets. Also I should note that the voltage on my brake wire to ground is actually only 1.3 V and my voltage on the regen brake wire is only .6 V which is troubling (I checked because I suspected there was a short there causing the motor not to go. Anyways shouldn’t it be 5v??). So I don’t know what to do.

OK. Well I can't figure out your problem from here but some ideas:

1) If the controller lets the wheel spin freely when the controller is connected and powered down, then it's not a shorted FET.

2) If the throttle button enables the controller (which would be odd - why not leave it on?) then I would suspect a bad brake input, thus turning regen on all the time. If the throttle button just applies the throttle, then I would suspect the Hall sensors (see below.)

3) This is concerning: "the bullet connectors for the hall phase power melted." The Hall sensor wires carry almost no current, so that indicates a catastrophic failure inside the controller (and/or inside the motor.) Did you mean "bullet connectors for phase power?"

4) In any case, if your motor does use Hall sensors, I'd start there. Verify they are getting 5V and that each one turns on and off as you rotate the wheel slowly. If they do, then try different combinations of them to see if it's a phase mismatch.

Yes. I meant the phase power rather than hall power. My hall sensors are powered and delivering up to 5v depending on how I spin. The throttle button enables the controller (i.e. If you turn it off the bike is off, and the 5v supply and 12v supply is off). So it’s something to do with the controller. I’m sure that brake wire and regen wire are both low voltage, so I think there is an issue there. I tried to give them 5 volt but it still didn’t allow the motor to go. Maybe the chip is just dead.

 

[420b]

I think I’m done messing with much current controller. I’m going to buy this one: https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F302033173933 I hope it can reach higher top speeds, and it’s a perfect fit for my 2 36V hover board batteries in series!