AboutKen Myers Expertise I can answer beginning, advanced and expert questions about electrically
powered R/C model aircraft, and many questions about R/C model aircraft of
all types, except helicopters. I`ve been building, flying and designing R/C
model aircraft for 40 years.
Experience I have been building and flying radio controlled model aircraft since 1960. I'm the president of the Electric Flyers Only, Inc., located in southeasten Michigan. I'm a past president of the National Electric Aircraft Council. I'm vice-president of the Midwest R/C Society. I was president and main founder of the UFO (Union Lake Flying Organization). I've built and flown most types of model aircraft except helicopters.
Question I am new to r/c planes. I have bad bearings in my Eflite brushless and need to purchase a new motor. My speed control is a 25A and my motor is a 1,880kv. I have been finding deals on brushless motors that are from 2,600kv up to 4,500kv. I do not know what will be compatible with the 25A speed control. How does amps translate to kilivolts?
Answer Hi Eric,
There is no direct relationship between the motors Kv rating and the amps. The Kv is a rating of how many rpm the motor will turn from the volts out. There is a voltage loss through the wiring, connectors, ESC and motor, so volts out is not the same as volts in. For a replacement you want a motor with approximately the same Kv, 1880 in this case, and at about the same weight. A motor with a Kv somewhere between 1750 and 1950 and within about 25 grams of weight would be an equivalent replacement.
The Kv on the motors you were talking about are all too high to be an equivalent replacement.
