# More general questions on electronics

Discussion in 'General Electronics Discussion' started by hyudryu, Mar 20, 2010.

1. ### hyudryu

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Feb 24, 2010
I want to make a electromagnet. I wound up 30AWG magnet wire around thick Iron core and when i connected it to my power supply, 16V 3A, It got HOT very quickly. Should i have more coils? will that help decrease heat? And for the battery, it will drain an normal AA battery pretty quick right?
And recently, i took apart my old broken hard drive and i found a stepping motor. How do i make it work? Where can i find the datasheet? I tried connecting it to DC and AC. It just makes a click and stops and shorts

2. ### (*steve*)¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥdModerator

25,482
2,830
Jan 21, 2010
You will need many many more turns. If it's getting VERY hot really quickly, then perhaps you need 20 to 100 times more turns.

After you have made your electromagnet you should measure the resistance, use this to calculate the current at the voltage you are using, then determine (based on the specs for the battery) whether this is a suitable current and how long the battery will last.

Stepper motors require special circuits to drive them. If the motor was the spindle motor of a hard drive then it's not a stepper motor. The last time consumer hard drives had stepper motors in them was probably the late 1980's.

If you can get the part number you may be able to find a datasheet, otherwise google for people using hard drive motors.

This, for instance, took me about 2 seconds to find.

3. ### hyudryu

64
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Feb 24, 2010
After i realized that it was getting too hot too quickly, i winded up around 100 more turns and it still became hot, but not that fast. Should i wind it more? And If i want magnetism, should i use 2 AA batteries in series or a 9V battery?
And yes my motor is a stepping motor not a DC spindle motor. I already have a few of those.

4. ### (*steve*)¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥdModerator

25,482
2,830
Jan 21, 2010
Look for stepper motor controller then. Does your stepper motor have 4 or 6 leads? You may need to determine which leads are connected to which internal windings.

Not a hundred more turns, a hundred TIMES MORE turns.

Or thinner wire.

Or both.

5. ### hyudryu

64
0
Feb 24, 2010
Oh i use 30AWG. And yes my stepping has 4 leads and i soldered on 4 wires