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I have some motors to be used in copters, can anyone tell me:

a) if they are BLDC

b) how could I find what current they would draw and their power ratings?

c) what ESC should I use for it

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Firdous
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If they only have two leads, they are not BLDC, probably just brushed DC motors.

BLDC motors generally have 3 leads for the windings. Sometimes there are even more leads for Hall effect posistion sensors.

Olin Lathrop
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  • Ok, any idea about finding the power ratings – Firdous May 07 '17 at 13:26
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    @Fird: Look in the datasheet. If that is not available, then these are not motors to use for demanding applications. Otherwise to get a rough idea, use a lab supply and slowly ramp up the voltage until the motor gets to a reasonable speed. Leave it like that for a few minutes while monitoring its temperature to make sure it doesn't get too hot. If it doesn't load the motor a bit an measure its current. – Olin Lathrop May 07 '17 at 13:31
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    In copters- you mean you are going to rotate a propeller? You will need very high speed, so brushed DC motor will probably not fit at all, or maybe fail quickly. Brushless motors for drones look very certain way:http://www.robotshop.com/media/catalog/product/cache/1/thumbnail/9df78eab33525d08d6e5fb8d27136e95/u/a/uav-brushless-motor-a2208-17-1100kv.jpg –  May 07 '17 at 13:41
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They are N60 size brushed motors, probably with weak Ferrite magnets and metal brushes. As such they are not likely to be suitable for high power/weight applications.

Brushed motors wear out with use. Even high quality coreless motors only last a few hours when used in model helicopters. Second-hand motors recovered from old equipment already have some wear so they will last even less time.

You should look for motors which are specifically designed for helicopters of the size you want to power. Quadcopters need matched motors with identical characteristics except two are timed for clockwise rotation and the other two anticlockwise. These are often sold as a set of 4.

Bruce Abbott
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  • I normally see ratings on motors in the form on Amps, can you recommend me greater than what value of amps should I look for in a brushless motor for quadcopters – Firdous May 08 '17 at 06:07
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    Brushless motors are usually rated in Watts. A motor can be wound to work on high or low voltage which will effect the Amp rating, but the power rating will stay the same. kV (velocity constant) tells you how fast it can spin on a particular voltage. Prop size is critical because prop power is proportional to rpm^2 and prop diameter^4. That's several factors to consider and calculating performance is tricky, so I suggest looking for a motor size, kv, prop and battery that is designed to fly a heli whose all-up weight is about the same as yours. – Bruce Abbott May 08 '17 at 06:39