Quote:
Originally Posted by BrianG
Well, I read about 7 pages of that thread before I got tired of the general whining. Man, some racers are such whining p*ssies! Sorry, but it's true. This is a hobby and meant for relaxation isn't it? Where did they lose grip with reality?
Anyway, from what I gather, they are removing the regulator (not clear if it's the UBEC or some other regulator IC - probably linear due to the dropout voltage), flashing some special 1s software, and fiddling with settings.
Some things I see that are wrong but most don't seem to have the intelligence to think of it (or maybe just so worked up with their stupid debating):
- Instead of a receiver pack, use an DE AnyVolt micro to step up the 1s to whatever they want for the receiver/servo. Weighs a lot less and the 1.2A rating should be adequate for their use. Maybe add a capacitor to the output to help cope with the current spikes.
- Measuring output voltage at the motor wires with a meter is meaningless, even with a true RMS meter. The output of these things is square wave, not sine wave, which is what RMS is supposed to measure. The best way I can think of (other than using an o-scope) to see how much voltage is being output to the motor would be to put it in brushed mode, add a ~470uF capacitor at the output with a ~100 ohm bleeder resistor, then measure DC voltage. I say brushed mode because the voltage at the wires won't switch polarity as long as you stay in the forward range. In BL mode, the wires are omnipolar depending on which coil is being fired. The capacitor simply filters the square wave to a smoother DC signal that any meter could measure. The resistor is just there to bleed off any momentary voltage spikes, if any. And to get a true comparison, they should measure the battery with the same meter to get a "calibration" reading.
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I was looking at the Oscope in my garage yesterday and decided to hook it up to to my speed control. The output phase to phase is actually a pretty good looking sine wave with just a little distortion (not the waveform but noise on the waveform). When you look at a phase referenced to battery negative the top of the wave is slightly concave. I think phase to phase, using a meter would show an accurate RMS value. I was wondering if a lower Kv motor might look different but then my wife made me put up Xmas lights so...I didn't get to try a lot of the things I wanted to and I am out of town until Wed. Then I leave again on Thurs.
The test setup I used was:
MM and 7700Kv
2S2P A123 just about dead
OLD BK 10Mhz dual trace O-scope
Used my radio and just set the throttle trim so I could adjust the scope.
Jeff