From: Chuck Simmons
Organization: You jest.
X-Mailer: Mozilla 4.61 [en] (X11; U; Linux 2.0.33 i586)
Subject: Re: Hard disk inductance, how to simulate/measure?
Date: Thu, 17 Oct 2002 05:17:27 GMT
NNTP-Posting-Date: Wed, 16 Oct 2002 22:17:27 PDT
The little lost angel wrote:
> If I didn't get it wrong, all motors causes/have inductance.
> So how do I measure the inductance of an hard disk drive or PC fan,
> and what do I use to simulate it if I want to make a load tester?
> I understand inductance can be created/simulated using a inductor coil
> (or something like that) but it seems to me that unless the coil field
> collapses/re-inflate there would be no effect, right? Thus if I use a
> DC power supply on that inductor, it wouldn't show anything unusual,
> Also, what is difference/effect on a DC power supply for a device that
> draws 20W resistive power and one that draws 10W resistive, 10w
> inductive? Or is there no such possibility?
If a fan motor is a brush type, you can directly measure the inductance
using an AC signal generator and a resistor to measure the inductive
reactance at some frequency. If the fan is a DC brushless type, it has
electronics inside and you will be unable to measure anything directly
about the coils. Hard disk drive motors are technically AC synchronous
motors and coil inductance is easily measured. In another post I explain
how hard disk spindle motors are usually driven by the drive
... The times have been,
That, when the brains were out,
the man would die. ... Macbeth
Chuck Simmons firstname.lastname@example.org