Help - Isolation transformer

Thread Starter

bloguetronica

Joined Apr 27, 2007
1,372
Well, I need an isolation transformer with the following specifications:

Primary:
220V AC

Secondaries (isolated from each other, not tapped):
230V AC (could be 460V AC, but I think those don't exist, so I will use a full wave voltage doubler instead)
6.3V AC (300mA minimum, for the heater)

This transformer is for an oscilloscope CRT. I think if I got a 1:1 isolation transformer, I would be glad (I can add another transformer to supply 6V to the heater). The objective here is to have 600V DC (230VAC x 2 x 1.414VDC/VAC = 650VDC).

Could anyone recommend a trafo model or a manufacturer?
 

awright

Joined Jul 5, 2006
91
If you use a separate transformer for the CRT filament, be sure that it is insulated for the DC voltage to ground that it will be subjected to. An ordinary off-the-shelf filament transformer will not stand up to the DC voltage.

awright
 

Thread Starter

bloguetronica

Joined Apr 27, 2007
1,372
If you use a separate transformer for the CRT filament, be sure that it is insulated for the DC voltage to ground that it will be subjected to. An ordinary off-the-shelf filament transformer will not stand up to the DC voltage.

awright
Well, in my situation, isolation will be really needed. But I prefer a "plate and filament" transformer (or a "valve power" transformer), since those are more adequate. I will use a 500V AC secondary and forget about the voltage doubler.
I need a transformer suitable for 230V AC (I think I cannot use one for 220V AC, and a trafo for 240V AC would be ineficient).
 
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