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. I assume that
the relay contacts are doing that as well which probably doesn't hurt anything.
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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