HiI went back and looked at the PDF of the manual, which states that the high voltage used in the one test is 500 volts DC! So it is very likely that the winding feeds a voltage multiplier circuit and the actual AC voltage may be a lot less than 420 volts, perhaps 210 volts or even less than that. This would explain the lower number of turns in the winding, reported a few posts back. At no-load, a voltage double produces twice the peak to peak supply voltage. So if the output was 500, then the PP would be 250 v, and the RMS about 0.707 of that, I think. That would be close to what is predicted by the turns count reported.
Sorry my bad , should of read , 420v @ 3mAI see an interesting problem with those numbers. This transformer is, I think, physically rather small. When I consider the voltages and currents listed: 420 V x 3A =1260 watts, +6V x 32A =192 watts +13V x 0.40A = 5.2 watts, a total of about 1450 watts, that transformer is not close to large enough to supply that much power. So I am guessing that secondary #1 is really 420 volts at 0.03A =12.60 watts. And looking at the wire sizes that is more reasonable.
Main board the transformer feedsI went back and looked at the PDF of the manual, which states that the high voltage used in the one test is 500 volts DC! So it is very likely that the winding feeds a voltage multiplier circuit and the actual AC voltage may be a lot less than 420 volts, perhaps 210 volts or even less than that. This would explain the lower number of turns in the winding, reported a few posts back. At no-load, a voltage double produces twice the peak to peak supply voltage. So if the output was 500, then the PP would be 250 v, and the RMS about 0.707 of that, I think. That would be close to what is predicted by the turns count reported.
Yes they are a bit, but they are ok, they are meant to get quite hot, bit of a design fault having them so close to the board .Where the high wattage resistors terminate it looks rather Fried!!
Going to the trouble already of re-winding.Yes they are a bit, but they are ok, they are meant to get quite hot, bit of a design fault having them so close to the board .
Yes if I sort the Transformer out am going to lift them a tad higher.Going to the trouble already of re-winding.
I would be inclined to to a little remedying, the board already looks like it is started to char, and only get worse.
If there is room, the resistors could do with stand offs or stand off style.
HiIt is a VERY poor design to have high wattage resistors mounted against a circuit board, as the photo shows. In addition I see what looks like a cracked small resistor just below the relay next to those high wattage resistors.
The high wattage resistors should be spaced at least 1 cm, or half an inch, off the circuit board to allow adequate cooling air and avoid charring the board material.
AND I see the green and grey wires at the terminals marked "400 volts", but O do not see evidence of any voltage multiplier circuit. Of course there is a fair amount that does not show at all, or possibly the doubler circuit is on the opposite side of the board.
I was about to mention, most through-bolts have at least and insulator on one end or the other, both ends not really needed.I am going to insulate the screws as per pic
HiI was about to mention, most through-bolts have at least and insulator on one end or the other, both ends not really needed.
You need to insulate the bolt stem as well as the head for a short distance in.
Keeps the bolt off the lamination's.
by Jake Hertz
by Jake Hertz
by Jake Hertz
by Aaron Carman