Inductance of a little PM motor

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#1
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Using an oscilloscope and a waveform generator, I get the inductance of this little 12v permanent magnet motor somewhere between .45 and .91 uH. Can't get closer than that because my waveform generator gives me steps 20KHz, 50KHz, 100KHz and so on.

 

Does this value sound reasonable?

 

The only specifications I can find for this motor are:

 

10,500 rpm at 12v with no load

3.8A stall current

The largest known prime number: 282589933-1

It's easy to stop breaking the 10th commandment! Break the 8th instead. 

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Forgot I already had a thread on this since like a year and a half ago.

The largest known prime number: 282589933-1

It's easy to stop breaking the 10th commandment! Break the 8th instead. 

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I would expect milliHenries for motor windings on an iron core.    Pure speculation.   I have not done the maths.

 

David.

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As a sanity check, you could use your scope to measure the RL time constant of the current through the motor winding.

 

 

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Why does it matter?

 

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#1 This forum helps those that help themselves

#2 All grounds are not created equal

#3 How have you proved that your chip is running at xxMHz?

#4 "If you think you need floating point to solve the problem then you don't understand the problem. If you really do need floating point then you have a problem you do not understand." - Heater's ex-boss

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I do connect a capacitor (I would try 100n first) in parallel with the motor and use a 1.5V battery for example and briefly give it a little juice. Scope what happens and do the math. You should get a nice sine wave.

 

Me.

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The largest known prime number: 282589933-1

It's easy to stop breaking the 10th commandment! Break the 8th instead.