Checked winding resistances on the bare transformer (from a Shaving adaptor).
About 55 Ohms Black to White. That's the 115V outlet
About 117 Ohms White to Red, so likely the outer.
Black to Red is the 230V. So Black is common. Actually I think in the US the white is neutral and black is live, but the transformer likely has 4KV isolation.
I have a drawer full of KPB 210G bridge rectifiers. 2A 1000V (though bag erroneously has 4000V. I always check several sources).
Warning, danger Will Robinson!
One hand in pocket and NO TOUCHING with fingers or iron till working meter shows safe!
No sort of trip or fuse is any help for safety with an isolated transformer. Ironically the initial test setup is safer with nothing earthed (except soldering iron).
Put 330 K resistors across two ex-SMPSU 470 μF 200V caps and wired in series. Added to bridge and get about 365V no load. Added white wire to centre tap as it's nominally 1/2 way. Still same voltage.
Considered how to add a pair of voltage doublers. Same circuit as a peak detector. The white wire even unconnected won't work as relatively it has no AC compared to ANY point on the rectified side.
So for layout convenience I put 1 μF 400V met-polys in series with red and black wires (input to bridge) and completed the two voltage doublers with 2 x 1N4007 each. A 1 μF 400V met-poly on each output.
Remeasured everything:
Bridge gives 370 V DC
Negative Doubler with its first diode cathode and output cap (1 μF 400V met-poly) connected to OV gives -230V.
Plus Doubler with its first diode anode and output cap (1 μF 400V met-poly) connected to the +370V gave OL. Got out AVO on 1KV DC. Read 720V. Realised there was another range on DVM 0000 instead of 000.0 and it read 709V.
Don't use the cheap DMMs with a 750V range at over 300V! I've seen those die with a blue flash at 460V on the 750V switch setting!
Obviously that's all with nearly no load. Works as expected. Nothing went bang. No-one died etc.
Next is the lamps, FETs and 12V supply for adjustable gate voltage and powering panel meters etc. I see a drawer full of giant FETs that make TO200 look like wimps. I've a box of old heatsinks from scrapped CPUs. Worst case should be less than 15W.
No PCB or tag strips. A tag strip would be best. Stripboard isn't smart at these voltages. Currently bridge, resistors, 4x 1N4007 and 4x 1 μF 400V met-poly hanging off the pair of tied together 470 μF 200V caps with centre tap to transformer centre tap.
About 55 Ohms Black to White. That's the 115V outlet
About 117 Ohms White to Red, so likely the outer.
Black to Red is the 230V. So Black is common. Actually I think in the US the white is neutral and black is live, but the transformer likely has 4KV isolation.
I have a drawer full of KPB 210G bridge rectifiers. 2A 1000V (though bag erroneously has 4000V. I always check several sources).
Warning, danger Will Robinson!
One hand in pocket and NO TOUCHING with fingers or iron till working meter shows safe!
No sort of trip or fuse is any help for safety with an isolated transformer. Ironically the initial test setup is safer with nothing earthed (except soldering iron).
Put 330 K resistors across two ex-SMPSU 470 μF 200V caps and wired in series. Added to bridge and get about 365V no load. Added white wire to centre tap as it's nominally 1/2 way. Still same voltage.
Considered how to add a pair of voltage doublers. Same circuit as a peak detector. The white wire even unconnected won't work as relatively it has no AC compared to ANY point on the rectified side.
So for layout convenience I put 1 μF 400V met-polys in series with red and black wires (input to bridge) and completed the two voltage doublers with 2 x 1N4007 each. A 1 μF 400V met-poly on each output.
Remeasured everything:
Bridge gives 370 V DC
Negative Doubler with its first diode cathode and output cap (1 μF 400V met-poly) connected to OV gives -230V.
Plus Doubler with its first diode anode and output cap (1 μF 400V met-poly) connected to the +370V gave OL. Got out AVO on 1KV DC. Read 720V. Realised there was another range on DVM 0000 instead of 000.0 and it read 709V.
Don't use the cheap DMMs with a 750V range at over 300V! I've seen those die with a blue flash at 460V on the 750V switch setting!
Obviously that's all with nearly no load. Works as expected. Nothing went bang. No-one died etc.
Next is the lamps, FETs and 12V supply for adjustable gate voltage and powering panel meters etc. I see a drawer full of giant FETs that make TO200 look like wimps. I've a box of old heatsinks from scrapped CPUs. Worst case should be less than 15W.
No PCB or tag strips. A tag strip would be best. Stripboard isn't smart at these voltages. Currently bridge, resistors, 4x 1N4007 and 4x 1 μF 400V met-poly hanging off the pair of tied together 470 μF 200V caps with centre tap to transformer centre tap.
