compessor spike fuse blows

we are having problems with out fuse on the spike for the compressor
it continually blows
is there any reason for this
is there anything that can be done

Did you check for shorts in your wiring? Also, you could be putting too much power through the spike… it can only handle so much before the fuse blows. :cool:

The compressor can have high (>20 A) instantaneous loads - the rules allow for the 20A fuse (yellow) to be replaced with a 20 amp thermal reset circuit breaker (black). This will protect your compressor and not have the compressor trip off line intermittently.

is a thermal reset breaker the same kind of breaker that is used on the breaker panel

Yes it is

Do any other teams seem to have this problem? It’s never happened to us. Maybe you should replace the spike

We use an auto-resetting breaker for the spike. This is wired seperately from the normal bus for all of the speed controllers/spikes.

We had a fuse blow on us mysteriously with the compressor spike. But I just replace it with a new one and it has been fine ever since. Check to see if you have the compressor wired backwards. I hear from our head of pneumatics that under no circumstances is the compressor to be wired backwards(reverse polarity). It might be fortunate that the fuse is cutting the power before any major damage happen to your compressor.

We had the same problem last year. It happend a few times during matches until we found out we could replace it.

Yes you do have to be careful with the pump because it can cause the breaker to trip, easiest solution is to use the autoreseting breaker.

As to the question of weither other teams have experiencd it, yes i have experienced it, and i have seen it happen to other teams, its just one of those things you have to deal with, the kit isn’t perfect but by and large its a great set of parts and the compressor works great for our purposes.

Hope this fixes your problem, if you still contunue to have problems you should check for shorts or grounding issues. Then again it is always good to check for these, so you might want to go ahead and do this anyways.

Several years ago, we had a problem with blowing the compressor
fuse. The problem was traced to a bug in the RC program what was
intermittently reversing the polarity on the compressor while it was
running. Look for bugs in your code that might be doing this,
and you can wire the spike so that an intermittent reversal does
not apply reverse polarity power to the compressor (only shuts it off).

Yeah, it might be best (if it is legal) to run the ground wire from the compressor straight to ground on the breaker panel (not through the spike), then run the positive wire to the positive side of the spike. Then hook up the spike normally, and replace the regular fuse with the auto reset breaker and you are good to go. That way even the worst programming screw up couldnt possibly run the compressor backwards, the only way to make it run backwards would be to plug the battery in backwards. But dont do any of this unless someone (more knowledgeable than me) confirms that it would work and is legal.

We lost two relays to the compressor, until we decided that the 120psi pressure switch is crap and switched to the TI analog pressure sensor we got a few years ago. Now that it’s fixed in the program, it works fine. We had the compressor stuttering on and off due to a slight air leak (don’t they all have slight air leaks?) and that stupid switch. The relays we lost didn’t work (!!) when we replaced the fuses with more 20a ones, although we didn’t try the AR breakers. The relays act dead, even though there’s no evidence of damage (these are also the relays that fall apart, so we got a chance to see the internals–no evidence of “magic smoke”)

Re. Russel’s idea:

Keep in mind, you wouldn’t be able to unhook the Spike from the ground, since its internal circuitry that drives the relay draws some power.

Aside from that, it seems like it might be legal. I don’t know.

What would be easier, look at the relay outs on the RC. you see that the pins are labled Gnd, Fw, Rev. I forget which one, since i don’t have aRC with me. You could simply spread apart your pwm cable somewhere in the middle, then cut the wire for Reverse. That would also make it impossible to reverse the compressor (unless someting is connected backwards) and I think that would be more legal than rerouting the 12v current. I would put male/female insulated spade connectors on each side of the PWM cable you cut, so you can plug them back in if needs be.


I think this has something to do with the “in-rush” of current that occurs when the compressor turns on. Initially, it takes a lot of current to get the piston moving in the compressor, but after that it only draws about 10 amps. I’m pretty sure this is why they allow the circuit breaker on the spike in place of the 20A fuse.

Even if you’re not having problems, I would suggest switching to the auto-reset breaker. It would really stink if your compressor didn’t work during a match :slight_smile:

Our team had the same thing happen. It turned out polarity was reversed, and, when the compressor was running on a low main battery, it liked to blow. Check poles - not with the spike light, mind you, but a multimeter. If your voltage is negative, then you have a problem.