[BC] Transmitter Safety

[DHultsman5 at aol.com]

In a message dated 4/29/2008 1:13:37 PM Central Daylight Time,  
jeff at rfproof.com writes:

The 120  supply should have been off the three 
phase in some manner, preferably a  transformer.



*********************
 
In my opinion this transmitter especially in the combined mode had too many  
places to get bit by AC and DC.  Also it had too many hidden fuses in the  
center cabinet.
 
As a straight 20 kW. there was a seperate feed for the three phase power  
supply. Then the rest of the transmitter cabinet was fed from a 220 V single  
phase breaker.
 
Now take two transmitter and there are four breakers required.  The  center 
cabinet probably had a 220 V breaker and a 110 V  breaker,  plus all of the 
remote controls were at 110 VAC. To turn  everything off there were six breakers.
 
I also personally got bit by the bias supply and had another engineer bit  by 
the 2 kW supply for the 250B's due to a stuck contactor on that rig. The main 
 3 phase was turned off buy not the low voltage 220 V single phase  breaker.  
 
 Collins and Continetal have only one breaker to turn off and it all  went 
away even in the external supply transmitters.
 
Glad most of these are gone or in backup mode. I love today's  transmitters 
with low voltage DC remote control circuits.  I don't know how  many times I 
have been bit on the terminal boards of remote control units in the  back of 
racks that switch 110 or 220 VAC to transmitters and phasors.
 
Dave



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