[Hallicrafters] Current Limiter question

[w6we]

Hello Charlie, I have used current limiters for decades. These were 
installed in "transformerless" TV sets and radios in the 50 and 60's. Used 
to get them from TV repair shops. I started using them in filament 
transformers for 3cx15500 tubes to limit inrush current. Using a clip-on 30 
amp meter i found the tubes would peg for many seconds before  setteling to 
the normal 10 a draw. Using limiting, peak current was 15a max. 8877 tubes 
are expensive. Never had a filament problem again. I haven;t bought any for 
many years. Used to be about $2. Harbaugh wants $20 for their universal 
transmitter model but it uses relays to bypass series resistors. You need to 
determind what the normal current needs to be and determine rating of the 
limiter use ohms law to see what size is required.  Mike G w6we
----- Original Message ----- 
From: "Charlie" <pincon at erols.com>
To: <hallicrafters at mailman.qth.net>
Sent: Saturday, June 21, 2008 7:04 AM
Subject: [Hallicrafters] Current Limiter question


> I've been looking at the Mouser & Digi-Key catalogs and am a bit confused 
> by the many types and specs for what is called an "inrush current 
> limiter". These are apparently negative temperature coefficient 
> thermisters that have a relatively high resistance at room temperature 
> which lowers rapidly as they heat up from current flow.  Seems like just 
> what we need to limit that dreaded current surge when using solid state 
> rectifiers in place of tubes in our older boat anchor radios.
>
> There are several pages of them listed and I'm not sure exactly how to 
> determine which ones are the correct types to use.  Has anybody used any 
> of these successfully?   If so, what types /specs have you used?
>
> Thanks, Charlie k3ICH
>
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