Victor on fire

[P1h3r1e3d13]

For what reasons have your Victor speed controllers failed?

After having run our RC and all motors on and off for some time today, we heard a loud SNAP! like an electric arc and we saw and smelled a small whiff of electrical magic smoke. We killed the power, checked everything for shorts, grounds, disconnections, etc. We found nothing and after bench testing the only suspect part (a Victor), we reassembled and tried again. This time we were greeted by large quantities of magic smoke, glowing red transistor heat sink and 2-inch orange flames from a different Victor, and killed the power again. Turns out that transistor was cracked. We replaced that speed controller with a spare, and same thing: more magic smoke. We're pretty sure its from the replacement Victor.

Any ideas?

FYI:
The controller is hooked up, like our other 3 drive motor controllers, via a PWM Y-cable (2 motors/side) and power is through a 40 amp fuse and to a small CIM motor which (along the other on that Y-cable) drives a default gearbox.

We double-checked everything at each step after the first problem and we're pretty sure, at least, of the following:
No other components failed: wires, fuses, cables, motors, etc.
The motors aren't working against each other (though this is still a slight possibility)
All controllers are Victor 884s with blue writing (this is certain).

[Al Skierkiewicz]

On the list of Victor failures...
1. Metal shavings inside the device.
2. Driving a locked motor over a long period of time.
3. Two motors fighting each other in a multi-motor drive.
4. Short on the output or power wiring connected backwards. (A hint on this one and the two previous ones is a buzzing sound coming from the circuit breakers)
5. Metal shavings inside the device. (yes I repeated myself, but this is the cause for about 90% of failures.)

[coldabert]

Try replacing the PWM cable. Our team has had problems with the Y-cables before and they routinely stop working. I would go back to regular PWM cables. Also, make sure that you have sufficient cool air flow from your fans




Make sure that your PWM cables are properly oriented

[P1h3r1e3d13]

Originally Posted by Al Skierkiewicz

On the list of Victor failures...
1. Metal shavings inside the device.
2. Driving a locked motor over a long period of time.
3. Two motors fighting each other in a multi-motor drive.
4. Short on the output or power wiring connected backwards. (A hint on this one and the two previous ones is a buzzing sound coming from the circuit breakers)
5. Metal shavings inside the device. (yes I repeated myself, but this is the cause for about 90% of failures.)

Good call on that - a postmortem on the dead Victor revealed some small aluminum shavings. Our theory is that when we blew out the speed controllers with compressed air, we had the power and motor wires removed and we blew shavings into their screw holes. Inside those connectors is where we found the most shavings. We're still not sure about the second failure - we are in the process of removing, disassembling, inspecting, cleaning, reassembling, and remounting all of our Victors.

Thank you, Mr. Skierkiewicz, for being so helpful to us and everyone else here.




And coldabert, thanks, but before this problem, the Victors' LEDs tipped us off to a PWM cable problem, so we checked all the cables with our handy-dandy multimeter and as of the time of failure (and right after) they were all good.

[Andrew Blair]

With your replacement: According to IFI, if you wire the victor's power leads backwards, they will be destroyed. I don't know if this means fire and smoke, but could be the cause.

[Alan Anderson]

Older (red-label) Victors would fry approximately instantly if given power backwards. The newer ones have reverse polarity protection, which apparently means that they will trip a circuit breaker in just a few moments after power is applied backwards.

[Kevin Sevcik]

FYI, we had a victor tripping a circuit breaker and couldn't figure it out. It turns out we'd lost a screw at some point and someone had replaced it with a longer one, thus shorting the output to ground.