[AMRadio] BC1-J Mod trans. is fine.

[Donald Chester]

>From: KC4QLP at aol.com

>For short term transmitting and what have you..you could get by with
>this.However I have seen where somebody did float their
>chokes,transformers,and reactors and it caused a fire in a commerical
>operation. Luckly somebody was right there to put the fire out..otherwise 
>it
>would have resulted in a total loss of equipment.

Bob,

I am curious exactly what caught fire, and how the floating chokes and 
transformers might have caused it.  I have done this for over 35 years and 
never had any problems.  My first high power rig lost a filter choke two 
weeks after I built it because the tar in the potted choke broke down, and 
began to conduct and shorted to the grounded case.  I fixed it by removing 
the choke from the case and getting all the tar off, and mounting the 
unpotted choke on ceramic standoffs.  That got me thinking and I have 
floated everything  since.  At present I use rubber shock mounts on the 
filter chokes, which run at 2000 and 2600 plate volts, to isolate the 60 hz 
vibration from the metal cabinet as well as the high voltage.  The mod 
transformer and reactor are bolted to blocks of material that looks like 
hard rubber. No arcovers, fire or blown transformers since I built the rig 
in 1970.

My smaller rig runs only 1350 plate volts, and I use the mod transformer and 
reactor from a Gates BC-1T, that runs 2600 plate volts.  The mod xfmr and 
reactor are bolted directly to the aluminium transmitter cabinet.  I didn't 
bother to float these because they are rated at so much more voltage than I 
am running.  I see no difference in performance in the two rigs.

Don K4KYV




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