View Full Version : Running with/without caps on ASF Boards

2010.02.22, 11:37 AM
How many of you run the two 102 caps on your motors still when using ASF 2.4ghz boards ? I've always ran the caps on the motors ever since I started mini-z'ing back in 98. But as of last week, I ran afew motors without the caps with no radio glitches or loss of performance. I've been out of the game ( electric cars ) for a loooong time and wondered if you still have to run the caps still. Your input is appreciated. Thx gang.

Roger Serafin

2010.02.22, 12:19 PM
I always use the caps. I dont see how it would make much of a difference with power without them... If anyone has a motor dyno (not just a motor tester), they should check to see if there is a difference...

2010.02.22, 12:32 PM
Thanks EMU for your response. I had the add " loss of performance " for the new guns getting into mini-z motor tech. I know that the caps aren't used for motor gains ( increasing torque or rpms). They are used to filter any RF noise that is generated from the motor / brushes so that the rx will not pick-up any noise that may cause interference with the signal when using AM/FM channels. Now that most of us are using ASF ( 2.4ghz ), is it still necessary to use the caps to filter out any RF interference ? Again, I used afew motors this past weekend without any radio interference on my old school EX-1 Mars radio with ASF. I just want to see if anybody else out there is doing the same thing. Thx again.

2010.02.22, 12:51 PM
i think that the caps not only reduce feedback to the board but also help reduce arcing across the comm face,this will make your motor last longer:)

2010.02.23, 11:21 AM
maybe i'm crazy...but i always figured that caps were a means of storing excess energy momentarily, and then released when throttle is ramped back on.
An example of how this would work would be under braking...

2010.02.23, 04:12 PM
The way those capacitors are wired, they can't store any significant amount of "boost" energy for you. The ones that are used for boost are wired in parallel with the battery pack: the moment you hit the gas (when the motor current spikes), the boost caps are there to supply all the current your motor demands until the batteries can catch up -- that's what gives the boost effect. These smaller caps that are wired between the motor terminal and the motor can are there (as far as I know) just to smooth out electrical pulses when your brushes pass a gap in the commutator.

Yes, you can run motors without the caps with 2.4GHz (I've done it when I lose the caps and am too lazy to put some new ones on), but I'm pretty sure MK2 is right in that they reducing brush arcing to preserve your commutator for longer.

2010.02.23, 06:16 PM
This is cool. Thanks everyone for your input.