Hi,
just a quick question.
Since the RS775-18 is an 18V motor, how would you attach it to the robot given the 12v battery…?
Thanks!
Just like any other motor.
The RS775-18 is rated for operation up to 18v, but is wired and run at 12v on FRC robots.
Although it’s a motor that is capable of running at 18V, we just run it at 12V. Thus it’s like all the other motors. Nothing special in the hookup to a Jaguar or Victor (or Spike).
I think technically it’s rated up to ~22 volts, but then again, most of our 12 volt motors are rated up to ~18 anyway.
550’s melt their brushes around 22v and 775’s aren’t too happy beyond 24v.
Is this from experience?
One year, the kit apparently included FP motors rated at 6 volts. At 12 volts they apparently had ridiculous power (~400watts) but they also had a nasty habit of dying frequently.
That year was awesome. And you’re right- they were about 100 watts at 6 volts. Doubling voltage quadrupled power for brief excursions to around 400 watts. If you were lucky enough to have gotten those motors, and lucky enough not to have fried them, you could do a lot of interesting things with that much power in that small a can.
Most of the motors in FIRST have historically been sourced from automotive applications, so they are happiest at around 12 volts. Car charging systems not being the most precise things a lot of the motors are expected to have a fairly wide operating range before any problems arise.
The RS-775’s are, I believe, originally made for a cordless drill. The upside of operating below it’s design voltage for us is that, although they are a little weaker ounce for ounce, they have a more safety margin before frying then the 500 sized motors.
Yes it is from experience.
The 775’s are in most cheap to mid range cordless 18v drills with two speed transmissions. Most cheap 18v drills that are single speed have 550’s in them.