How to measure inductance of a fuel injector?

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Sergey89
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How to measure inductance of a fuel injector?

Post by Sergey89 »

I tried to measure the inductance of a Bosch EV14 fuel injector and got a strange result. I used a cheap meter from ebay (http://www.ebay.com/itm/1pcs-New-L-C-Inductance-Capacitance-Multimeter-Meter-LC200A-Tool-lm-/291099820083?pt=LH_DefaultDomain_0&hash=item43c6e6c033).

3.3 mH @ 85 kHz
91.6 mH @ 1640 Hz

Inductance is heavily dependent on the frequency.

What is a correct way?
Sudo
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Joined: Mon Mar 17, 2014 12:53 am

Re: How to measure inductance of a fuel injector?

Post by Sudo »

It seem with an oscope and signal generator, it would be easy. See http://daycounter.com/Articles/How-To-Measure-Inductance.phtml Something like the DSO quad seems like it would work.

It seems something is missing with the method in the link. It would make more sense to include the DC resistance of the injector and output resistance of the signal generator, and everything else in the loop. Based on the article, you need to turn the sinewave to produce a voltage of the series resistor, where Vr = Vs * 0.5 * R / (Rtotal). Then, apply L= R*sqrt(3)/(2*pi*f).
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