Re: Measuring an RSG

To: tesla-at-pupman-dot-com
Subject: Re: Measuring an RSG
From: "Jim Lux" <jimlux-at-jpl.nasa.gov> (by way of "Terry Fritz (moderator)" <twf-at-verinet-dot-com>)
Date: Sat, 05 Dec 1998 10:08:04 -0700
Approved: twf-at-verinet-dot-com


> What is the easiest way to measuring the break rate of an RSG without
> using a tachometer or a strobe light?  The rotary I have is 24
> rotating electrodes hooked up for 10 in series at one firing time. 
> The gap is set at .040" for each electrode for a total of .400".  In
> my arsenal of test equipment I have 3 current probes and an o-scope. 
> I'm assuming that you would connect the probe to the lead that is
> attached to the movable tap on the primary?  The o-scope I'm using is
> a Techtronics RM503 (an old tube type).

You can get an optical tachometer accurate to 100 rpm at a hobby shop for
about $20. If you position it so that you get each electrode shading the
photocell, and you set the tach for the 2-blade prop position, the number
it reads will be 12 times the actual rotational rate (because you
effectively have 12 times the number of blades), so your actual resolution
will be around 8 RPM.

If you want to measure the break rate while running, just hook up a short
wire antenna to your oscilloscope to pick up the RF emissions from your
coil. You'll see the pulses. Then, measure the time between pulses off the
scope and calculate your break rate from rate = 1/ time....


> 
> Thanks,
> 
> Rodney
> 
> 
> 
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