Halden ?, Jim too

One part that doesn't make sense to me is the one about the 5V windings being "connected" to the B++ windings.? They're only connected when the insulation fails and the arc is active, and only one of them is known to do that.? ?

Maybe ?I’m ?guilty of using insufficient wording ??"connected" to the B++ windings. ?I meant ?"connected ?thru the 5R4” to the very HV windings.

?I still cant think of an accurate simple expression. ?Is that any help?

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The other part that doesn't make sense to me is "When one 5 volt heater winding is at +800 RMS".? RMS is a way of quantifying an AC signal over time and is not an instantaneous value.

thats probably me too. I agree that it may be easier to use instantaneous values. ??As I see it, there a +800 RMS"

for one half cycle and a -800 RMS" half cycle ?also ?each half cycle of the HV takes its turn at grabbing the filament winding and sending very pos or very neg, with the peaks being ?800*√2? which is 1131.3708499 according to google.

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My hi-pot testing uses DC.

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I didn't measure the 800 Vrms directly because I don't want such high voltages around when I'm working alone.? So I used the secondary of another transformer to apply 20 Vrms to the primary and then measured the voltages at various taps on the secondary.? All measurements used a Keithley 2000 DMM, so I'm confident that the RMS values are correct.? Then, I assumed linearity and multiplied my result by 5.ok? Now that I wrote this down, I see it was an error - I was trying to think too fast!??? I should have multiplied by 5.8.? I would use 6 assuming a 120 volt primary but it may well be rated at 115, but we don’t know, do we? ??So, where I wrote 800 in this morning's post, it should be 919.? 1130 should be 1300, 1100 should be 1260, 2230 should be 2560, and I should probably turn my Bertan up to 2600 V next time. ?

you effectively had the turns ratio? measured, ??

I was only wondering if Hammond ?had the same turns ratio, they said ?120 /880volts ?or a ?1:8 ?ratio

I don’t know enough about Hi-pot, especially DC and on used transformers, so…

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If the 5V secondaries are likely to be 10 turns, then both 5V secondaries and the 6.3 V secondary are likely to be on the outer layer of windings and accessible after digging through a few layers of crisp paper and varnish.?

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Maybe I could find the arcing spot and add insulation to repair it.? I'm now tempted to open up the transformer and look.

Good , It might be creepage around the very ends, so test before you get the scalpel out , ?oh ?I’m late hope the tipoes fix themselves on the way.

don

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