[BC] Re: Saving Your Own Life

[Dennis Cope]

Some of the problems deriving 120 vac come from the 3 phase configuration,
weather it's a tapped delta or a 208 Y.
All the transmitters I work on for the weather service are 208 Y.



-----Original Message-----
From: broadcast-bounces at radiolists.net
[mailto:broadcast-bounces at radiolists.net]On Behalf Of DHultsman5 at aol.com
Sent: Thursday, October 20, 2005 23:07
To: broadcast at radiolists.net
Subject: Re: [BC] Re: Saving Your Own Life


In a message dated 10/20/2005 10:33:26 PM Central Standard Time,
radiotech at bellsouth.net writes:


Milton, I hate to say this but if you took from one of the 120's to
ground/neutral, You've probably just violated code. I think it's been
since the early 70's that you were no longer allowed to do that.  The
proper way being a 240-120 step-down transformer.

***********************************8




Every FM20H that I was involved with had two AC feeds.   A 220  VAC single
phase feed for the blowers, control, low voltage, driver and screen
voltage,
filaments and exciter.   The control voltage provided  the plate on coil
voltage.

A 220 VAC feed  three phase with step start coming into the same  cabinet to
a contactor and step-start circuit in the transmitter cabinet with  the ac
going to the power supply cabinet and a three phase plate transformer for
the HV
DC.  When the plate on control voltage is applied the HV goes  on.

The problem was you always had to turn off both breakers to be safe.   You
are correct this would not meet code presently.

D

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