Re: CIM Motor Capacitors
 

Yes, the solution is to not accelerate so quickly. Motor noise isn't causing the problems you are experiencing, it's safe to say. What's happening is that while trying to accelerate quickly, your send out far too much current to your motors, which results in a massive voltage drop on the system. This voltage drop will cause things like the radio, and possibly Crio, to shut down. You probably either need to instead tell your drivers to be easier on the throttle, implement a software safeguard against reckless behavior, or some combination of the two.

Additionally, partially charged and old batteries just like to exacerbate the problem described above. While a new one may be capable of putting out enough current to keep the voltage sufficiently high, a bad one will surrender.

Re: CIM Motor Capacitors
 

Me?!?

Re: CIM Motor Capacitors
 

It was Raul,
He said that he seen a couple of teams make the same mistake.
Blew us away, because everything was working on the test frame. When we moved everything over to Lunacy robot some how that got changed.

Lesson 1: Move over stuff one thing at a time.
Lesson 2: Take picutes before hand. Use them as a reference.
Lesson 3: Labels! What to where.


You can learn a lot from making mistakes - even more from fixing them.

Re: CIM Motor Capacitors
 

A healthy battery can put out enough current to trip the main breaker without browning out the cRIO.

Re: CIM Motor Capacitors
 

Not exactly, the Crio power supply on the PD will continue to output 24 volts until the battery voltage falls below ~4.5 volts. The analog jumper in module 1 monitors the battery voltage and when it falls below 5.5 volts, the Crio output is inhibited to allow the battery voltage to rise with no load. Sort of a no-battery backup battery.

Re: CIM Motor Capacitors
 

How much current does it take to trip the main breaker.

Re: CIM Motor Capacitors
 

A lot. It can withstand 600 amps for a second, if I recall. I'll try to find the curve.

Re: CIM Motor Capacitors
 

In a few seconds the main breaker would take ~720 amps to trip. The NP18-12 battery is only speced at 500 amps out into a short circuit at which point (at full charge), it is dropping 5.5 volts just across the internal resistance of the battery ignoring any other losses internal to the battery. 500 amps will drop another volt across the #6 wiring ignoring the resistance of the main breaker, Anderson connector, crimps and terminals.

Re: CIM Motor Capacitors
 

If you have a link to the spec for that could you post it please.


So it is. Interesting. The 2009 battery spec says 720 amps for 5 seconds.

Re: CIM Motor Capacitors
 

What are you running besides your four cims? Did this problem show up during Duluth? If it did, you guys managed it pretty well. After the communication dropped, were you ever able to get it back?

Re: CIM Motor Capacitors
 

We are also using 2 of the smallest banebot's, a window motor, and the compressor.

Re: CIM Motor Capacitors
 

The main breaker sheet is on CD already. You just have to search to find it. The actual spec is 600% over current for a few seconds and several minutes at 200%.

Re: CIM Motor Capacitors
 

The main circuit breaker is Terminal Supply's CB3-SM-120, which is actually a Cooper Bussmann 18X series breaker (probably a 185120F). Their characteristics are here (from the manufacturer, see page 32 printed/34 PDF), or here (directly) or here (for an older spec sheet from FIRST).

According to that diagram, some breakers may last for up to 3 seconds before tripping at 720 A.

Re: CIM Motor Capacitors
 

The Terminal Supply P/N CB3-SM-120 that AndyMark markets as their P/N am-0282 is spec'd by the manufacturer Cooper Bussman at 440 amps nominal for 5 seconds.



[edit] I see Tristan beat me to it. Nominal 440amps, range 352..528 amps for 5 seconds.[/edit]

Re: CIM Motor Capacitors
 

Does this alarm anyone?

We're using this thing as a switch, not a breaker.