24V Motors for 2010?

Hey this is probably somewhere in the paperwork, but does anyone know where you can buy a legal 24 v motor for the robot.

Also the new black Jags say they take an Input of 24V and can power a 24V motor

Since the Battery we use is 12 V how does the Black Jag receive a 24V input, I am assuming there is something on the PDB such as a Voltage Doubling Circuit.

Sorry these are probably noobish questions but i am more of a software guy.

The only motors allowed are those that came in your kit of parts (with the exception that you can purchase extra 12V CIM motors for a total of 5 CIMs). Hence, there is no legal way to use a 24V motor this year, even if the Jaguar would support such an option technically.

Our robots use 12 volts. The maximum voltage for the Jaguar is 24V, but it works fine at 12v. And since we can only use the (12v) motors that come with the kit, you couldn’t use a 24v motor anyways.

It wouldn’t hurt to spend an hour or so reading the rules, too.

http://usfirst.org/roboticsprograms/frc/content.aspx?id=452

You also seem to be a skip over section 8 guy. You are only allowed to use 12 volt motors. They are the ones in the kit and up to 3 additional cims.

There are no legal 24V motor options for 2010.

The black Jags can take up to 24V. They’ll operate off of 12V just fine as well.

Ok cool,
I figured as much. I know in the rules it was very specific about motors but i thought that there might have been a purpose/reason for the change to 24 V (obviously there is one but not necessarily for FRC)

We didn’t buy them because we thought they were more powerful anyway. It was mostly because of the Firmware they come with looked like it would be fun to play with.

Thx all

Many motor controller designs are migrating to the 24 volt standards as 24 volts allow motor designs to use less current to achieve the same power in the same size. By using lower current, the loss in wiring becomes less critical. IFI also has a 24 volt version of it’s Victor line.

For sake of not starting a new thread, has anyone tried running the current motors, like the CIM, Denso or Fisher price, at 24v and seen if they can handle it? I was thinking about testing a fisher price, but was put off by the potential 30000 rpm freed speed (explosion? ::ouch:: )

You’re going to kill a Fisher Price in short order. It’s not going to be able to handle the heat generated at 24V.

I have used a CIM at 15.4 (dual 7.6 volt rechargeable cells) however the peak current in that system was only 14 amps. i dont know if a CIM would handle more current well. i believe the drill motors were rated to 18.8 volts.

Alex raised an interesting question about running the kit motors at 24V instead of 12V.

It depends on where on the torque vs speed curve you intend to run them.

Let’s say you’re running an FP at 70% NLS at 12V. If you jack the voltage up to 24V and keep the same torque load, you will get twice the speed (and therefore twice the power output) for the same I^2R heating. You could change the gearbox to reduce the output speed and get twice the torque instead. So in this case it’s not a matter of heating, it’s whether or not the FP (and the gearbox) bearings and rotor can withstand the higher speeds (40% higher than 12V NLS), and whether the dielectrics can withstand the higher voltage transients. This analysis ignores secondary effects such as eddy current and hysteresis losses in the magnetics which may become non-negligible at the higher speeds.

Let us not forget to consider the back EMF limiting the speed when running at 24 volts.