[Amps] Potter & Brumfield Relays

[Bob Maser]

I am converting an old Collins 20V-3 to use on 75 and I want to use the 
power cutback circuit.  This involves switching in some high wattage 
resistors into the HV line.  I have 2 P&B PRD type DPST relays that look 
like they will work fine.  I am concerned about using a relay that is only 
rated to 277VAC, 20A.  Since I will be switching up to 3200VDC, is there a 
safety potential here?  I do not intend to hot switch them, turn off the 
plate voltage, then switch.  The bases on these relays are made from 
Bakelite.  They are NOS and in good condition.  A friend of mine pointed out 
that with the HV there might be a problem with the proximity to the 24V 
coils.  The P&B relays are part number PRD60055.  The alternative is to 
switch the cutback resistors with a hefty ceramic rotary switch, or a pair 
of vacuum relays.

Would appreciate hearing comments from the group.

Happy Holidays,
Bob  W6TR