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[Amps] Filament Inrush Control

To: <amps@contesting.com>
Subject: [Amps] Filament Inrush Control
From: stevek at jmr.com (Steve Katz)
Date: Fri Mar 28 17:32:06 2003
K9VUJ, the relay in the AL-80 pulls in in much less than a second and barely
makes a sound.  Seems to me, it's more like 50 milliseconds and I can't get
my hand off the ON-OFF switch fast enough -- it's pulled in already.
However, that would be sufficient to do the job. -WB2WIK/6



> I have watched the HV come up when I turn on the AL-80A, it comes up 
> very fast and I find it hard to tell when it is at that point and the 
> relay clicks in.
> I'll try a dc relay, I think the ac relay on the 115 line (the AL80A 
> is wired for 220) maybe comes in too fast.
> tnx Phil
> 
> 73
> Dale K9VUJ
> 
> 
> 
> >  > The delay isn't really a key parameter. The big current surge is over
> >>  within a 3-4 mains cycles. After that, the current slowly ramps down,
> so
> >>  you can short out the series resistor as soon as you like. When the
> >>  relay pulls in, there is a second current surge - a step-up in current
> >>  to the normal standby level.
> >
> >When I design from scratch with a typical step-start circuit, I adjust
> the
> >delay on the relay until the reading on the HV meter is 2/3 the way up
> >to normal value. By this time, all surges are over, and the filter cap(s)
> >are almost charged. This assures that the step-start is not operating too
> >fast, nor is it hanging in too long, heating up the resistor(s) in series
> >with the a.c. mains. This saves a lot of set-up time if the power source
> >for the relay comes from other than the transformer being step-started.
> >
> >Just one of many ways to end up with an effective circuit.
> >
> >(((73)))
> >Phil, K5PC
> >
> >
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