I found my father's old arc welder, DIY I guess. It has one transformer with 9 primaries and 8 secondary wires (of which 2 outputs are thick copper wires) and two switches (220V – 0 – 380V and 0-8 switch). Switches are faulty, transformer is tested as follows: -All wires are separated from the switch and from each other-There are 9 red wires, 6 gray and 2 thick uninsulated copper leads to which the main cables for the electrode holder and ground are connected.-No wire has contact with ground. -All red wires have mutual continuity (primary of transformer)-All gray wires have mutual continuity-Two thick uninsulated copper lines have mutual continuity-There is no mutual continuity between wires of different colors, nor between any colored wires with thick uninsulated copper conductors.- The red wires were numbered at the bottom with numbers 1 to 7, two were not numbered and I marked them with 8-9A and 8-9B.- The gray wires were not numbered and I marked them with numbers 91 to 96.How to identify the transformer wires to which the input voltage needs to be connected. The moment I enable the input voltage, I can measure the output and sort it by voltage and connect it to the appropriate place on the switch accordingly.Is this three phase transformer?
Measured resistance is in table below, measured in ohms.
Measured voltage is in table below, measured in volts. Input 14V AC was supplied on transformer output.
Percentage of increased voltage, compared to Input 14V AC that was supplied on transformer output.
>>2813429each wire conforms to an amp setting. either amps were changed by changing a wire to a different socket, or a rotary dial with multiple contacts. post name and model if it's somewhere on it.
>Is this three phase transformer?no the wires are all on the same loop. I don't know the significance of the red vs gray wires. >>2813433you can use this table to figure the voltage output you would get by applying mains to the different groups (120v / (percentage / 100)) or (240v / (percentage / 100))It could be more complicated if it's meant to use series/parallel combinations. parallel can only be done if the voltage is the same (I don't see any but there could be some) but series can be done with any collection of coils, so long as they are not connected internally to one anotherfiguring the amps output is harder, I don't really know how to do that other than measuring. You might be able to use the resistance to calculate it but also ought to check the wire gauge to make sure it won't melt.
>>2813430I think what you use to measure coils is called a Henry meter.
>-All red wires have mutual continuity (primary of transformer)>-All gray wires have mutual continuityOh sorry I misread that. They are hardwired in series. So one end (presumably the first or last one) will get hardwired to N, then L will get wired to one of the other ones. You should measure voltage from the N end to each of the other ones, rather than each loop individually. You could also sum up the individual voltages if you are confident what order they are wired up in. That actually makes it a lot simpler because there are only so many ways it could be wired up and you can just try them. Still not sure the red vs gray significance. You could put them in series, maybe one is for "fine tuning" or maybe for 240v you put them in series and 120v use only one.
It's single phase. Did the machine have selection switches that these red and grey wires were attached to? and did you take photos of it before you took it apart? Generally a bad idea to take all the wires off the switches if they're not labelled, now they're all mixed up. If it was MIG power source I would say the grey wires are "coarse" control and red the "fine" control, but it's just a stick welder so idk. I fix welders for a living and if this came into my shop asking to put it back together I'd say it's not worth the effort.
fwiw the numbering is not in order. I think I have numbered them in order here.The biggest voltage is gonna be between the first and last wire. From there you can order them by the voltage from the first wire. If you add up the voltages of connected loops you should get the same value no matter which way you do it. e.g. 35.5+2.3 = 38
>>2813828>▶Great observation
Transformer coils are wound using voltage ratios. The turns ratio between the primary and secondary are what achieves voltage change at that specific ratio, the steel core creates the magnetic field that induces the opposite side winding. For 8-9A to 92 you achieved 7 volts using 14, so a 2:1 ratio if 14 is your primary and 7 is your secondary (secondary always notated as the 1, but they work both ways so hard to say which direction you went without seeing the winding). To achieve your intended target voltage do the ratios across each lead. Being a welder it's possible they backfed it to increase amperage at a decreased voltage, as amperage is more important and will be increased by decreasing the voltage.As far as amperage, another anon was correct in stating that transformer switches can be combinations of seriesing and paralleling segments of winding. For example in my field, distribution class, we may wind a coil in dual voltage configuration of 2400 and 7200 to 240 volts, basically can use on a 2400v circuit or a 7200v circuit after setting the correct switch position. The problem is 7200 may require 3 amps capacity while 2400 would require 9, as voltage and amperage are inverse properties. We can achieve this by a 30:1 ratio of all seriesed windings through the switch for 3A of 7200V, and then 10:1 in the other position with 3 segments of 10:1 paralleled together to achieve the overall wire size increase needed for 9A of 2400V.To put this back together you need to find a target voltage and amperage output and back-trace the switch configuration from there. Done it many times when dumb employees tore switches apart without labeling leads, it's a nightmare without having a wiring diagram up front. It's virtually impossible without knowing what the end voltage/amperage is to be.
>>2813818A Henry is a unit of inductance, so that makes sense.
>>2813429If you figure out the transformer and get it welding (you can buy welder panel QD fittings, Dinse being most like best for you as Tweco are for higher output/heavier cable) you might study DC conversions of cheap AC welders as rectifiers etc are inexpensive.
