[Amps] Heathkit SB-220/221 HV Transformer

[Robert & Linda McGraw K4TAX]

Typically the SB-220 runs some 2800 VDC at 600 to 800 mA.  This is some 1600
to 2200 watts DC input.  Thus the output is about 1000 to 1300 watts with an
average efficiency of 60%.  Yes the SB-220/221 transformer is a wee bit
light to make a 4-1000 cook as they like some 4000 to 5000 volts and are
rated to 6000 volts.

A transformer with a 3200 volt RMS secondary, a solid state bridge rectifier
and a 4 to 8 mfd capacitive input filter will produce some 4500 volts
DC........enough to make a 4-1000 talk.  Current required is only about 600
mA to reach legal limit output of 1500 watts.

Looks like a 3200 V @ 1 amp is adequate and then some.  However, the
statement made  is "would provide 3200V at 1 amp" which does not disclose
the actual value of the transformer secondary voltage.   The SB-220
transformer is a wee bit light   for a 4-1000 and remember too the SB-220
used a voltage doubler in the rectifier.

73
Bob, K4TAX


----- Original Message -----
From: "Vic Rosenthal" <vic at rakefet.com>
To: "Jim Isbell" <millenniumfalcon at cableone.net>
Cc: "Mail list Amplifiers" <amps at contesting.com>
Sent: Friday, August 01, 2003 10:02 AM
Subject: Re: [Amps] Heathkit SB-220/221 HV Transformer


> Jim Isbell wrote:
> > I have just acquired the above referenced transformer and plan to use it
> > to power my 4-1000A in a grounded grid circuit using an S-line (100
> > watts) for an exciter.
> >
> > The PO stated that it would provide 3200V at 1 amp in a bridge circuit.
>
> Does it seem reasonable to you that a transformer that was designed to
> power a 1 KW input (ICAS) amplifier would be adequate atthree times
> that?  Really?
>
> Vic K2VCO
>
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