Rusty-Gunn

Hello, this is my first post on this site, I just joined yesterday.
I have a question (actually, many questions, but one at a time, or I might get confused.) What does "KV" refer to, on brushless motors? Thank you.

Walt Thyng

My Feedback: (9)

KV means the same thing for all electric motors brushed or brushless. It is the rpm per volt that the motor turns. All electric motors have this constant, of course it varies from motor to motor. The motor will always attempt to reach this design rpm no matter how much load you put on it . This is what lets the smoke out if you stall the motor. In general the higher the KV the smaller the prop it can spin or v/v the lower the KV the larger prop it can spin. there is a relationship between the number of turns and the KV, but I'm not an E.E. so Ican't tell you what it is.

It sounds like you are new to e-power. I strongly recommend that you get on the Ampeer mailing list at [email protected] ,In my opinion this is the premier e-power newsletter. The articles in the archives can answer just about any question you have.
Walt

Rusty-Gunn

Thank you. Yes, I'm new to this, so I've been a lot of the older posts here, and have begun my education. Another post did mention this, but it didn't say a higher number relates to a smaller prop, whereas a lower one relates to a larger prop. Thank you.

Walt Thyng

My Feedback: (9)

Rusty, again, I'm not an e-e, but as I understand it KV is related to torque and torque is related to the numbers of winds. More winds lower KV, more torque. One way to get a grip on this is to look at motors used in Electric Ducted fans (EDFs). They are usually one or two turn (winds) motors and turn very high rpms. In order for me to use my Aveox 1010 2Y (originally intended for an EDF) with a conventional prop I had to add a gearbox. without gearing it would only spin a 7 in +/- prop, with 6/1 gearing I spin an 18/10 very effectively.
Walt

PS take heart. I am entirely self-taught on e-power. For the first 6 or 7 years I didn't know anybody else who flew e-power. I bought the mags, read everything I could on-line, made a lot of mistakes and had a ball showing the wet-power guys how wrong they were about what could and couldn't be done with e-power (-: One word of caution, in modeling we are fond of saying "buy cheap, buy twice." This aphorism is four times more true in e-power.