Controller failure after alarm trigger...

[Cornelius]

Damnit....

I just tested the alarm, and it works perfectly, but I think it has ruined my controller...

Now, as long as all three phase wires are connected, the motor cogs, even with power off and all plugs disconnected except the phase wires... Turning on the power and try to turn the throttle, the controller sounds a long beep.
if I disconnect the Green phase wire, the motor turns smoothly; with the green connected, and either of the blue or yellow disconnected, it cogs...

I am assuming one of the fets inside the controller has short-circuited?

This controller was ordered June 10. 2009; Am I eligible for a replacement from GM on the guarantee?

[Who42]

  These instructions may help you get your controller working again

[Cornelius]

No, but thanks anyway...
I threw all guarantee out of the window and measured the fets, and as I thought; one of them was totally short-circuited...
No controller-tricks could solve a dead-short fet which in turn shorts one of the phases in the motor...

I've replaced it with a similar one, but 'weaker'; 55V, 80A.. Still, it should be within normal limits of what the motor uses... (36V, 30A)
So far it holds up, but I haven't pushed the controller much yet; i've given it full throttle from standstill to max speed, and hit the regen brakes to a dead stop a couple of times, then taken a 'normal' ride, just a couple of km's, and the controller was just lukewarm, and still working...

I'll just have to see if it holds up, and keep an eye for a 'proper' replacement fet...

[Bikemad]

The external controllers may require more space, but at least it makes removal and repairs much easier.

I imagine FET replacement would be a lot more involved with a Magic Pie.
(You wouldn't be able to unplug the phase wires to pedal home easily either.)

Alan
 

[Cornelius]

I imagine FET replacement would be a lot more involved with a Magic Pie.
(You wouldn't be able to unplug the phase wires to pedal home easily either.)

This is a very good point when selecting motor model...
My elderly mother loves to bike, but she has problems with her knees, and she tested my bike and said 'I want one of those!' Imagine her have to walk a bike with a semilocked wheel tens of km's?! With an external controller, I can at least tell her over the mobile phone 'Pull all the fat wires out  from the controller!'...

Now why did my fet short circuited then?
As I said, I was testing the anti-theft alarm, wondering how much it took to trigger it. The motor was rattling much when the anti-theft 'locked' it... Are the anti-theft function very hard on the fets, or was it just a weak fet? (I'm guessing that to lock the wheel, the controller activates the regen brakes 100% in a pulsed fasion so to not cook either battery or fets? )
Though, I had also rewired the regen switch; I had it on the horn button, but now i've attached the brake-handle that came with the kit, and I tested it a couple of times by letting the motor free-wheel at full throttle and hitting the regen brake... I guess this also could kill a weak fet, if a weak fet was the problem...

Needless to say; I am now reluctant to activate the Anti-theft, so i'm going to buy a sturdy lock instead...

[Leslie]

Is there anyway to activate the anti theift alarm while the bike is in motion, say at 30kph down hill and trigger the alarm.?

That could certainly cause the controller to fail.

It's like a very strong regen and only there to stop the wheel from moving at all not slow it down when its already moving.

[Cornelius]

I don't know if the controller sense if the wheel are still before allowing activation of the alarm; if not, it's possible to activate it, and that would certainly be bad...

It would have been better to have a relay shorting the 3 phases of the motor when the alarm triggered...

[Leslie]

I don't know if the controller sense if the wheel are still before allowing activation of the alarm; if not, it's possible to activate it, and that would certainly be bad...

It would have been better to have a relay shorting the 3 phases of the motor when the alarm triggered...

Yes thats a good idea.  Actually  I am going to do just that form my bike with no wheel lock system.

Regardless of how your incident happened, these problems would be good to sort out.

Not everyone is going switch the wheel lock on while moving, but when I was told not switch my controller off while the bike was in motion and pinned for regen, I did exactly that, I thought it would be fine to switch the controller off going down a hill, I wanted to free wheel without stopping.  I blew it up.

I was shattered, I wanted to get my warranty.  I called my GM dealer and explained honestly what happened, and he gave me some GM throw out factory second controllers for $20 each.


I knew it was my fault but even now I believe this problem could of been avoided, if not then in the future. ]

When designing this controller, anti theft regen blah blah, I feel not every problem presents itself to the engineer straight away.

I have no idea how anti theift works electronically I was taking a guess.  It could be wired like you said, shorting the phase wires out is a good idea AS LONG AS THE POWER TO THE CONTROLLER IS OFF.

[Cornelius]

Yes, a relay that is 'Normally-Closed'; cutting the power to the controller would also cut the power to the relay, shorting the motor. This way there would not be any power usage either... Though this would present a problem trying to move the bike when the battery are completely flat. (Maybe add a hidden bypass switch?)

Now, connecting a relay this way, and in addition connect the controllers phase-outlets via the relay (contact to motor when the relay has power) would ensure disconnection of the controller from the motor in case of a relay power failure... (And thus no shorting of the controller.)

[Leslie]

I think as long as people are honest about how these things end up smoked we all can move ahead and GM can fix the problems when they arrise.

I'll be the first to admit most of the failures I've had have been my fault.  Admitting to myself my mistakes  has taught me more about this than I could ever expected.

GM are putting so much effort into this industry but the feedback needs to be precise.

Can you please explain to me how you tested the anti thieft alarm top give us an idea of how this failure has occured.

And

Can a GM rep please explain how the wheel lock system works electronically so we can understand this new technology better in order to discuss what has happened to this controller.

You may of just got a bad controller.  Luck of the draw.

[Leslie]

Yes, a relay that is 'Normally-Closed'; cutting the power to the controller would also cut the power to the relay, shorting the motor. This way there would not be any power usage either... Though this would present a problem trying to move the bike when the battery are completely flat. (Maybe add a hidden bypass switch?)

Now, connecting a relay this way, and in addition connect the controllers phase-outlets via the relay (contact to motor when the relay has power) would ensure disconnection of the controller from the motor in case of a relay power failure... (And thus no shorting of the controller.)

I use a relay in my power feed to the controller.

Its rated at 7000 watts or something.  I put some big arse caps between the coil contacts to delay the switching voltage.  I wait 100ms for caps to charge the bike to switch on.

The controller logic, driver power and relay power goes through a small switch and thermistor, and then splits into to two paths, one splits to an LM338 and the other to a precharge resistor to the controller.

When I switch it on I get precharge, the caps on the relay charge up and close the relay.  Full power no sparks.

 I could run more relays off the switch with no delay caps, so the motor is open for current right away.  But when I switch off the relay caps takes about a half a second to discharge.  The motor will short first then then power to the controller gets cut.

Or even if I go from my delayed relay, with precharge there is a moment where controller is on and motor is shorted.  This isnt as bad though.

I'll have to think of something better to get around the precharge stuff Ive done.

[Cornelius]

To be honest (Which i've been so far.. ), I cannot remember what I did last before I discovered the wheel cogged. (and therefore I cannot say with certainty what blew the fet... :-/ )

I had locked the crank-gear to the largest gear, so that I could remove the combined gear-shifter/front-brake handle and replace it with one of the handles from the GM kit with the regen-switch. (so far, I have used the horn switch for regen braking...) All that is well.

To test the regen handle switch, I gave full throttle, letting the wheel spin freely; released the throttle, and the hit the brake handle; it worked fine. then I did the same thing once more, but this time I didn't release the throttle. It worked fine; the motor accelrated again as soon as I released the brake.

To test the Anti-theft, I simply activated it; the bike standing still on its stand. I nudged the bike carefully, and the siren made some noise for a couple of seconds. Then I turned the wheel carefully, and the siren started and the blocking braking kicked in as it should. this I did a couple of times...

But I cannot remember which of the two things I did last...

I'm more biased to a weak fet that at last gave up, because I have 'demonstrated' the anti-theft for friends on several occations earlier, and the regen brake i've always used actively. (though I always automatically release the throttle when braking... Didn't do that in one of the test above...)

[Cornelius]

Regarding power on; i've reconfigured the battery switch, so the full power to the plug are always there, and added a 3'rd wire from the positive inside the battery pack, via the key-switch, and to the thin red +wire on the controller... This way, the anti-theft works as it's supposed to; turn off the power-key, and press the cruise button within 10 seconds...

[Cornelius]

No, the throttle are fine?

then I did the same thing once more, but this time I didn't release the throttle. It worked fine; the motor accelrated again as soon as I released the brake.

I HELD the throttle at full speed the second time I tested the brake...

I think you misunderstood?

As I have said earlier; I have replaced the fet, and i'm enjoying the bike every day now... So this discussion are now more to find out how/why the fet failed...

Edit:
Oh, you removed those posts I see... 

[Leslie]

Ok I took all that on board.

The nets playing up so I had not loaded all the messages before I hit reply.

Its the nature of the damage that is curious.  A shorted fet!

Which fet out of the six did you replace?