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I want to make my harddisk motor running but when I tried to give it voltage on different pins it jerks and stop I came to know it runs on continuous pulse.

How can I make it run by external voltage?

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up vote 3 down vote accepted

Oh you're in for a treat! Some four-pin motors, 555 timers, et. al. These should get you started:, BLDC controller, and Drive stepper-motors. Best of luck to you!

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If you want the adventure of building a controller/driver circuit that's fine but if all you want to do is get the motor to spin I'd look at a cheap Electronic Speed Controller ( ESC ) from HobbyKing or local RC store. ( $8 ) The kind that is used to drive brushless motors in radio control models. They're rated by supply voltage and output current. The voltage handling is often stated in "s" units. 1s = 3.7V (nominal LiPo cell voltage). Most work on 2 or 3 LiPo cells ( 7.4v or 11.1v )

These brushless motors are sensorless, using the undriven winding as a sensor source. I don't suppose an HDD motor needs a lot of current so a low current ESC would only be a few dollars. Here is a list of many low-cost speed controllers from Hobby King......

These ESCs are usually driven by an RC receiver output but you could provide your own PWM signal OR just get a Servo tester, which will give you a compatible control signal and a knob to play with. ( $5 at Hobby King)

If you're ESC has a BEC( battery eliminator circuit) then you can power the Servo tester from there instead of finding a separate 5V supply.

The ESCs operate on a 1ms to 2ms pulse width (freq 30Hz-50Hz) the same as the actuator servos. 1ms = 0%, 2ms = 100%

Remember, you will be powering the motor, and NOT the circut board. You can remove the HDD circut board all together. Power the HDD motor directly. ( 3 wires )

Pretty simple when you understand it. Ask anyone who flys electric RC airplanes or a hobby store to help you power this "brushless" motor. All eclectric RC airplanes use a ESC and those guys will know what you need. Good luck.

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