Current reversed on compressor spike controller

[dez250]

To state the obvious and make sure your using the right components below is a Victor Speed controller which has a fan on it:


and this is a Spike Relay Controller, which has NO fan attached:



One test you may want to do is to use a multimeter and check the continuity of the single wires of your PWM cables to make sure they aren't damaged. Also physically inspect the pins on the PWM cables to make sure they are not bent or loose. If you still haven't figured out the problem, drop me a pm or im and ill try to help you out more in depth.

[mechanicalbrain]

Yes we used a spike! It would be.... interesting to try it with a speedcontroller. I was talking about the fan inside the compressor. I assure you we tested every piece betwean the control board and the compressor and every one works! We just can't get the spike to get a signal from the boards relays (Tried multiple (MANY multiple) pwm cables). Its unlikely its the code because it stoped running while we were using it. We have to ship the robot to Capitol Clash tomarrow. Any help will be really usefull.

[Mike Betts]

Scott, Oz, et al,

You started off with a problem where you blew a fuse. Now it appears that nothing works at all. There is also confusion in your posts concerning Spikes versus Victors, LED indications, Polarity and (perhaps) PWM versus Relay outputs.

I'm going to ask you to take a step back and compose a description of your problem with some diagrams and/or pictures. Perhaps a code fragment as well.

You may have fallen into the trap of "breaking" several other things while trying to troubleshoot the fuse problem. As such, you may now have a multiple problem problem which is complicating your life.

The act of stepping back and documenting what you have can be very beneficial in these circumstances.

Regards,

Mike

[Gdeaver]

Does the compressor run if powered by 12 volts directly? Maybe your compressor is gone. If it runs check the amp draw.

[Al Skierkiewicz]

A lot of info is passing through this thread and we do want you running for the weekend. If what follows doesn't get you help, ask for some of the teams to assist when you get to the Clash.
As to the first post, tripping the fuse while turning is a good indicator of the start current demands of the compressor. Although it is rated for 10 amps that is "run" current, start current is more than twice that amount and under certain conditions we have measured four times that amount. (For a very brief time during start.) When turning, currents are very high for the drive motors. Tank style steering (where no wheels turn but motion is accomplished by speed differences between the two sides) are the one of the highest current demand drives you can use. (Belt style tank being the worst.) As the battery tries to deliver power during these high demands, the terminal voltage can fall below the point at which the compressor continues running. So the effect is turn, compressor shutdown, compressor restart, turn, shutdown, restart, etc. Each restart of the compressor is accompanied by a high current pulse that heats up the fuse and failure is the result. Replace the fuse and continue beating up the spike and failure will result there as well. So that in a nutshell is the normal failure in this application. However, you may have a different problem altogether since you have replaced the spike and wiring multiple times. I have to ask if the location is very tight and other wiring had to be disturbed to make the changes. There is a distinct possibility that 1) the spike was rotated when replaced, 2) the wiring to the spike was exchanged with another component near it, (another relay or controller), 3) the compressor has shorted, or 4)in replacing the fuse and/or spike, the wiring from the pressure switch was broken and your software is no longer receiving a command to start the compressor. High on my list are #4 and #1. A simple check of the switch wiring and connection back to RC is very easy to do. Checking on the orientation of the spike is also very easy to do. My rule of thumb when troulbeshooting a working device is "go where the last person was" which will be the spike replacement.

[mechanicalbrain]

I would like to thank everybody for their help. We finally got everything up and running. What ended up happening was a series of unrelated events that caused only the compressor to stop working. First our pwm cables to the had been damaged and kept causing trouble. At this point it worked 50% of the time. After replacing these the compressor stopped working all together. This is when we started this post. All of a sudden it decides to work this morning (still don't know why?) after extensive testing with a multimeter but it wouldn't turn off!! Our code to regulate it didn't seem to work. After testing the pressure sensor we found that the pwm for it was plugged in but it wasn't getting power! Well thats when we remembered that not all our pwms were long enough to reach the controller so instead of splicing them and soldering two together we had just connected them and taped them and the splice had come apart! After fixing that and reinstalling our original code we finally got it to work properly.

In summery Ive learned two things. One: make sure everyone next year knows the proper way to wire (and make sure were super neat). Two: I REALLY hate pneumatics!

[sciguy125]

It seems that Murphy decided to pay you a visit.

[Alan Anderson]

Originally Posted by mechanicalbrain

...I REALLY hate pneumatics!

Why? Everything you mentioned breaking was electrical.

[Al Skierkiewicz]

Originally Posted by mechanicalbrain

Well thats when we remembered that not all our pwms were long enough to reach the controller so instead of splicing them and soldering two together we had just connected them and taped them and the splice had come apart!

A good way to connect two PWM's end to end is to tie a knot and then tape the connectors and knot.

[Alan Anderson]

Originally Posted by Al Skierkiewicz

A good way to connect two PWM's end to end is to tie a knot and then tape the connectors and knot.

That's true of just about any in-line connector. We regularly tie overhand knots in extension cords and serial cables when we have to use more than one. That way the tension on the wires tends to pull the connections tighter instead of apart.

[mechanicalbrain]

Yeah thats what im going to do now. And the reason i hate pneumatics is that murphy would have a field day with them. Their are too many weak points in a pneumatic system that can cause the entire system to fail. At least if you loose a drive motor it only hampers you (this is dependent on the robot)!