[Amps] How about INRUSH CURRENT PROTECTOR

[Jim Thomson]

Date: Wed, 27 Dec 2017 13:03:08 -0500
From: "WK1W-Ivan Shapiro" <WK1W at ivanshapiro.com>
To: <amps at contesting.com>
Subject: [Amps] How about INRUSH CURRENT PROTECTOR

<I followed WA8SAJ's advice for protection.
All my tube rigs "see" a 110/120 INRUSH CURRENT PROTECTOR made by Ameritron.

That is fed by a variac, also suggested by WA8SAJ.

My L4B, though it has step-start, it "sees" a 220/240 ICP from Ameritron.

The latter might be overkill, but is insurance.

 

73  Ivan Shapiro  WK1W

##  The outboard, external  ameritron inrush current protector IS a step start circuit, uses the same resistor + relay to
shunt the resistor.   Only difference is its in an external box, used on amps that never came with step start. 

##  Be careful when using a variac to control the main 240 vac going Into a kw tube amp.   If its not sized big enough, 
it can easily harm the dynamic regulation of the B+ supply.   The peak current every 8.3 msecs  through the diode board 
is huge, a lot higher than your plate current. 

##  and  be careful if using a 240 vac variac to feed an amp like a SB-220, L4B, ameritron etc.  Lower the b+,
and you will also have lowered the fil V !!  

##  On my hb amps, I use a variac to control the fil V only, not the B+ supply.   

Jim   VE7RF