Wires Twitching

For some reason when I connect my 12V battery to my control board, the cables connected from the PDP to my Talon SRXs twitch and produce a clicking noise. Why is this? Thanks in advance :yikes:

…wat?

It might be helpful to post a photo of your setup too, just in case somethings off.

A clicking noise usually suggests the breakers are tripping on the PDP. Do you have the SRX’s wired correctly, or shorted?

Possessed by demons?

Thermal expansion could cause motion, but if there’s enough thermal change to cause them to visibly “twitch” you probably have bigger problems on your hands…

Any chance it’s the circuit breaker that’s making the click noise?

I’m going to take a large step here and say that something is definitely off.

A photo would be helpful however.

The twitching can be produced by magnetic fields resulting from high currents, which would also trip you breakers. Can you insure that nothing is wired backwards?

This happened to me last offseason. The twitching was caused by the breakers tripping (which was the clicking). It turns out I had wired Everything to the motor controllers backwards. Once I switched the wires correctly the problem went away.

Also, the talon srxs don’t have reverse polarity protection, so you may have fried them already if this was your problem ::ouch::

We had this exact same problem - check that your battery terminals are plugged in the right way (black to black, red to red). It turns out the robot doesn’t like when you run a current through in reverse.

Otherwise, check all the breakers on the pdp and your connections.

It is most likely that you either have at least one reversed connection or short circuit of some sort.

Disconnect your battery now. Before you connect your battery again, print out the wiring diagram linked below. Thoroughly check that every single wire is correctly connected. Verify the polarity (and colour) of every connection. Use a DVM set to Ohms and probe across the red and black pairs of each channel of the PDP you are using. The DVM should not read below 500 Ohms. Use a flashlight and look at where every wire goes into your PDP and look for anything reflective. This would indicate that you have a stray strand that may be touching the neighboring wire of opposite polarity. Follow each wire from the PDP then out to each motor controller to make sure they have not been cut on sharp edges. Then have at least one other person repeat these checks. It should take each person at least 15 minutes to do these checks adequately. Don’t “hurry too fast”.

As Classified stated, it is possible that you have damaged your motor controllers if they were connected with their input polarity reversed.

**http://wpilib.screenstepslive.com/s/4485/m/24166/l/144971-wiring-the-2017-frc-control-system
**

Short circuit currents will cause opposing magnetic fields in the wires in the short circuit current loop to repel each other as Sam pointed out. Those high currents will cause the breakers to trip. It can be fun watching bundles of cables as thick as your arm jump when doing short circuit testing on high-power electrical equipment :smiley:

*Hey Crunchy, have you abandoned this thread?

He might be too busy rewiring the robot or replacing rather expensive parts :frowning:

Kinda reminds me of the parable of the guy running down the street with his bike because he doesn’t have the time to stop and get on it.

Yeah, but think of all the time he’ll save on the trip back home when he can afford to stop and mount! ;->

The Amish have a saying: “The hurrieder I go, the behinder I get.”