On Aug 12, 2005, at 10:42 AM, TexasRF@aol.com wrote:
>
> An interesting characteristic of an AC relay is that it buzzes like
> crazy as
> the voltage ramps up to the value it needs to fully operate.
That's why a DC coil relay is needed for step-start.
> I assume that
> the relay contacts are doing that as well which probably doesn't hurt
> anything.
Does hotswitching @ 60Hz sound okay to you?
>
> If the tube has a directly heated cathode, the filament typically has
> about
> 1/10 resistance cold vs. hot. The limiting resistor would be a big
> help in
> reducing the filament current at turn on and that is a good thing.
>
> Solid state timers are available from Grainger for about $20, and are
> adjustable over a wide range of times. They simply connect between one
> of the relay
> coil terminals and the AC supply voltage; could not be easier to
> install and
> work perfectly.
>
> 73/K5GW
>
>
> In a message dated 8/12/2005 12:21:11 P.M. Central Standard Time,
> theo.bellamy@spirittelecom.com writes:
>
> silly me .... that works with a B+ supply, but probably not with a
> filament
> xmfr. Sorry ....
>
> Theo
>
> -----Original Message-----
> From: amps-bounces@contesting.com
> [mailto:amps-bounces@contesting.com]On
> Behalf Of Theo Bellamy
> Sent: Friday, August 12, 2005 1:00 PM
> To: amps@contesting.com
> Subject: Re: [Amps] Soft Start
>
>
> Why not just put the soft start relay coil across the primary. Since
> there
> will be a big voltage drop across the step start resistors - leaving
> very
> low voltage across the transformer primary until the filters charge -
> the
> relay will be timed "naturally". This will also protect against an
> open step
> start resistor since the relay won't ever fire in that case.
>
> Theo K4MO
>
>
>
> -----Original Message-----
> From: amps-bounces@contesting.com
> [mailto:amps-bounces@contesting.com]On
> Behalf Of Rich
> Sent: Friday, August 12, 2005 12:21 PM
> To: Amps
> Subject: [Amps] Soft Start
>
>
> OK guys I made the subject soft start , but that about the only thing
> right this time. The resistor should be big enough , 50ohms 100w. It
> all worked one part at a time but when I hooked it all up together my
> 60
> main power relay chatters , I am going to rewire and not run the coil
> supply for the 60 amp through all the relays. I have the 120- control
> voltage daisy changed the coils and I think I am getting VD. That aint
> good.
> I am able to adjust the delay as required from .15 sec to 180 with
> the
> Dayton relays so ignore my original statement about 10sec delay on
> HV, I
> will adjust it.
> More when I know more.
>
> Rich , kd0zz
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Richard L. Measures, AG6K, 805.386.3734. www.somis.org
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