engineermike
Well-Known Member
I was drawing a parallel to an AC motor because the premise of speed control of a DC Brushless motor is more like an AC motor than DC. The frequency of alternation between 0 and X volts is what determines the speed. AC motors aren't constant speed, but they run near sychronous to grid frequency OR some other frequency generated by a VFD/inverter. The DC Brushless controller is more like a VFD/inverter than a typical DC resistor or PWM driver.A digital signal is not a sign wave, its a square wave if anything. This wave doesn't make the voltage going to the pump AC. The reason why I would still call it DC voltage out is because the polarity is not flipping. Positive and negative on the pump is always positive and negative.
Anyone saying the pump remains at a constant speed like an AC motor..... Is wrong. It has to change speeds in order to change flow rate.
What I'd like to know is if the Brushless controller senses the system voltage increase and, in turn, use logic to allow higher frequency/speed to be commanded. If it doesn't, then that just means higher voltage will result in lower current for any given speed and power, which will help prevent over-amping but won't directly increase fuel supply.
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