Description: This is a simple, but very powerful stepper motor with a 4-wire cable attached.
This is a Bipolar Motor.
Based on 8 ratings:
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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.
I own three of these motors, and use them for video production, microphotography (controlling the positioning of equipment), and robotics projects. They seem reliable, have enough torque for all of my needs (so far), and can be nicely driven either by H-bridge chips like the L293D, or by more feature-rich motor drivers like the EasyDriver.
But as I just discovered, working with SLF radio frequency, which is what you are generating when switching these motors (and all steppers) at typical speeds, is not always carefree. The RFI/EMI produced can interfere with sensitive input pins on microcontrollers, and in my case, an IR receiver module (Vishay TSOP38238). The solution is pretty easy, though - if a part is being influenced by EMI, shield it by surrounding it with grounded conductive material. You can buy shielding, or make your own. I am shielding my IR receiver module by placing it on a piece of PCB with a large ground plane that sits between the IR receiver and the stepper controller, output traces, wiring, and motor.
Another thing I like about this motor, which is perhaps a little odd, is the very long cable. I usually only need half the length. I cut it in half and braid it. But the other half I cut off? It makes excellent stranded hook-up wire! So hey, bonus hook-up wire :)
For hooking this motor up to projects in a reversible but still dependable manner, I recommend 4-pin mini XLR plugs and jacks. They can be pricey but are worth it because accidentally disconnecting a running motor while attached to a controller can destroy the controller. I have also used S-video (4-pin mini DIN) connectors in the past, but after trying mini XLR, I found it to be a far superior solution.
Last thing to note - you can dissemble these motors to see how they work, and put them back together easily. Once opened up, you just have to tug on the rotor a bit because there are fairly strong magnets in there. You can also reverse the axle so it comes out the other side - I had to do that for one project to get the motor mount where I wanted it.
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