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Description: This is a simple, but very powerful stepper motor with a 4-wire cable attached.
This is a Bipolar Motor.
Based on 7 ratings:
1 of 1 found this helpful:
This makes a great low RPM generator for windmill , waterwheel science fair projects .. puts out 6 Volts AC at about 70 RPM which will power 5 V. LED’s.
Bought this motor for a wind turbine (my university’s senior project). Ran it with a 3D printed 3-bladed turbine, with a NACA 2410 airfoil, 5.25" span and 1" chord with a 0.45" hub (so the inner radius of the blade is 0.45" and the outer radius is 5.7").
Test setup used a 9.65k ohm resistor connected to two rectifier bridges (one for each output) with 0.32V forward loss schottky diodes and 1000uF electrolytic capacitors from DigiKey.
At 6 m/s freestream velocity, turbine spun at ~460 rpm and motor produced 31V. At 9.2 m/s, ~985rpm and 61V. At 11.9 m/s, ~1420 rpm and 70.6V.
P=V2/R, so power at the three speeds was 0.010A, 0.385A, and 0.517A.
We also used the cheap circular stepper motor from sparkfun and it only produced 0.030A at 12 m/s and 1450 rpm.
EDIT: In an earlier review, I incorrectly assumed that the “friction” seen with this motor was due to the magnet rubbing against the outer walls. Actually, this “friction” was the detent torque - seen when the wires were shorted together. When used as a generator, the load (resistance) across the wires will determine the amount of detent when you try to spin the turbine.
A previous review wanted a universal mounting hub - we used SparkFun’s 5mm to ¼" shaft coupler to mount our blades, which could also be used with a 3mm to ¼" shaft coupler for other motors.
Very nice product, works as described, would be even greater if it had a universal mounting hub included…
i buy four parts, while 2 of them have problem with spring force and this stall the rotor when try to rotate it by hand
i fix it no big deal