On 6/9/17 2:38 PM, Ronald Reeland wrote:
Hi:
I picked up a relatively high voltage transformer at a Hamfest
recently. It is a sealed unit, gray painted steel housing, leading me
to think it is military spec. There are some abbreviations shown on
the transformer schematic that are not clear to me.
It has a tapped primary for 105, 115, and 125 volts. But also shown
is "535PWV".
And three center-tapped secondaries:
1. 1130 V RMS, .150 AMP DC, PWV 1070 2. 1190 RMS, .025 AMP DC, PWV
1070 3. 412 V RMS, .500 AMP DC, PWV 715
What does PWV stand for? "Peak Working Voltage" does not seem to be
appropriate, particularly on the primary.
Could that be max "voltage to core" (i.e. insulation rating). Center
tapped secondaries are usually used to drive a fullwave rectifier, so
the max voltage of the 1130V winding, relative to the center tap is
1.414*1130/2 = 799V
In some circuits, there might be a bias (e.g. a filament supply that's
floated at the cathode voltage, in a grounded grid, or grounded anode
circuit) That's the way microwave ovens are, for instance: the filament
is actually at the HV, so the insulation on the filment winding is rated
for twice the voltage of the HV winding (MO use a voltage doubler, and
one end of the HV winding is grounded to the core)
So you don't design for more voltage resistance than you need
(insulation costs money, mass, and volume)
And it appears the transformer is deigned for full-wave rectifier
circuits using the secondary center taps and the DC AMP rating are
maximum that should be drawn through the rectifiers. Does that sound
reasonable?
Yes
Transformer made by "Chicago Standard Transformer Corp, Chicago, IL.
Numbers on case are "TF1RX03YY", 672-1049-00, and CSTC 28447.