This happens again and again. Simple question. What leads are to be connected for a dual primary transformer if the polarity of the windings is not stated. This is an R-core transformer if that makes a difference. The transformer clearly states '115 volts Black-Red and Grey-Orange' are the 4 wires of the primaries, but there is no indication as to what leads need to be connected together for both primaries to be connected in parallel. I know that if I connect them out of phase, I am screwed. Here is a photo. To be clear, my home is 120 VAC and not 220 VAC.
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I think the phase is implied by the labeling. Join red and grey to each other and connect your 230V mains supply to black and orange. My transformers were similarly marked and that worked for me.
Ah. Just noticed you are the US so 115V supply. In that case connect black to grey and that goes to one side of your supply, connect red to orange and that goes to the other side of your supply.
May be worth cross checking with another US resident.
Ah. Just noticed you are the US so 115V supply. In that case connect black to grey and that goes to one side of your supply, connect red to orange and that goes to the other side of your supply.
May be worth cross checking with another US resident.
Thank you. That is what I was guessing for the color combination. Too bad it is not written in any way on the drawing. Ok, back to the soldering station.
If it said 0 -> +115V and 0 -> -115V, that would be different. Phasing is implied, but its easy to check if you can inject a small signal into a secondary with a signal generator - then the primaries can be connected IN SERIES and the overall voltage measured - one way will produce 0V, indicating they are phased in reverse (for series). Just bring the outer ends together for the parallel arrangement as you already have the same polarities joined in the middle. You can check again at safeish power levels with the signal generator (most are 50 ohm output and only a dozen volts - still treat the primaries as high voltage though).
i.e. if the windings are A--B and C--D and you connect A to C and measure 0V between B and D, connect B to D for parallel.
i.e. if the windings are A--B and C--D and you connect A to C and measure 0V between B and D, connect B to D for parallel.
Thanks Mark! That is a clever way to determine the unknown in this situation. Now if I only remember to do it next time around.
Having said that, yes, in fact I did notice the 0-120 reference at a second look. That is what made choose the wiring the way that I did. Wouldn't it be great if everyone could speak the electronic language? I have seen schematic symbols every now and then that I never had seen before. Went with my gut and got lucky. That is not the way to work.
Having said that, yes, in fact I did notice the 0-120 reference at a second look. That is what made choose the wiring the way that I did. Wouldn't it be great if everyone could speak the electronic language? I have seen schematic symbols every now and then that I never had seen before. Went with my gut and got lucky. That is not the way to work.
sure thing, connect the black and grey together and the red orange leads together to form a parallel connection and then use the series lamp to test, if the lamp glows full brught, then reverse one pair, then test again, what you are looking for is very dim lamp glow, meaning you connected the primary windings correctly.
If there's any glow its bad news.... The windings should have the exact same number of turns and thus cancel voltage very precisely, otherwise you will see large circulating currents in the parallel combination.
When the primaries are connected correctly in phase with no load connected there should be a dim glow (i.e.. not normal brightness, hence the name) using a low wattage bulb like 25 watts, and there should be some voltage on the secondary(s).
Mike
Mike