Disconnecting
this capacitor "cures" the excess current draw and
the chassis voltages come up fine (still running through variac at
reduced AC voltage with series light bulb as I expect this cap is
part of a "line voltage regulator".
The transformer is labled "C.V." (Constant Voltage?)
The cap needs to be there. An unloaded CVT runs hot and draws
more current due to the highly reactive load. A side effect
of storing power in a resonant circuit (floating coil and cap).
As the transformer is loaded the current remains the same but
more stored energy is transfered to the active load. I have
a Compupro Chassis, TEI and even a spare supply of that style.
I also have 120V/120V CVT for systems that do not have one
internally. They tend to run warm under normal cases. It
should with a modest load (auto headlamps are handy for this)
behave and also not blow primary side fuse(s).
By current switchmode tech they are scary but represent old
magamp thinking and are reliable devices.
Thanks - yes, I figured the cap needs to be there, but removing
it during low power tests identified it as the cause of the high
current draw - I guess I was not clear on this as several people
have emailed me to warn me not to run it without the cap.
But I think you have provided the information I needed - normally
I bring up a chassis with no load, initially at very low line voltage
to allow the big electrolitic filter capacitors to take it easy as
they reform.... But I've not encountered a resonant transformer
design before - if I understand you correctly, not having any load
at all is putting the transformer/cap into a state where it is drawing
excessive power - I will try supplying a load. Do I need to load all
of the windings, or will drawing from just the 8V supply be adaquate
(I would expect the latter).
Thanks,
Dave
--
dave04a (at) Dave Dunfield
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