Guess value of surge limiting resistor is an empirical question, start with
high value, observe response on scope....
Thought : use of incandescent lamp as resistor. Understand that tungsten
filament resistance increases with current flow, but I may be wrong on this.
Any opinions?
73
Barry
end
Barry Kirkwood PhD ZL1DD
Signal Hill Homestay
66 Cory Road
Palm Beach
Waiheke Island 1240
NEW ZEALAND
ph/fax 64-9-372-5161
www.waiheke.co.nz/signal.htm
----- Original Message -----
From: "Marcinio Afonso Stabile" <marcinio@terra.com.br>
To: <amps@contesting.com>
Sent: Wednesday, January 07, 2004 9:05 PM
Subject: Re: [Amps] Step start resistors
> Hi Peter!
>
> I am using thermistors as inrush current limiters, for a variable
frequency
> AC drives, in a pre-charge system, to limit the charging current on the DC
> bus capacitors. More information at Ametherm web site:
>
> http://www.ametherm.com/Inrush_Current/welcome.html
>
> I hope it could be a usefull idea. Here in Brazil, PY2WM (De Marco) tested
> this solution on the rebuilt of your Delta 1000 linear amplifier (4 x
811A)
> with sucess, using a thermistor removed from a surplus PC power supply.
See
> the description (in portuguese only, sorry!) at:
>
> http://geocities.yahoo.com.br/jkdemarco/Delta1000/Delta1000.htm
>
> 73!
>
> Marcinio Afonso Stabile - ZZ2TWT
> Jaboticabal - SP - Brazil
> http://www.stabile.eng.br/tubes
>
> ----- Original Message -----
> From: <peter.chadwick@Zarlink.Com>
> To: <amps@contesting.com>; <amps-bounces@contesting.com>
> Sent: Monday, January 05, 2004 8:41 AM
> Subject: [Amps] Step start resistors
>
>
> >
> > Any ideas on what values to use for step start resistors? In the past,
> I've
> > tended to choose a value from the available stock - something like 50
> ohms,
> > 100 watts, which limits the surge current to just over 4 amps. I expect
> > that a value such that the current won't exceed the full load primary
> > current of the transformer is probably best, but any suggestions?
> >
> > (I'll probably still use what's available in my stock of vitreous
> enamelled
> > wirewound resistors about 10 inches long and an 1 inch in diameter,
> > though!)
> >
> > 73
> >
> > Peter G3RZP
> >
> >
>
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
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