Einhell SGA165/1 wiring diagram and selection switch.

[dieselman]

Hi, I have an old Einhell SGA165/1 which has been a good welder for my use, but recently stopped providing any spark voltage on power settings 1, 3, 5. It still worked perfectly on settings 2, 4, 6.

The wire feeds on all settings, so it appeared the rotary switch wasn't passing power to the transformer coils on selections 1,3,5.

Assuming the selector switch was the issue I've taken it apart and am sure I've lost a couple of the springs, but also really need a wiring diagram of the machine so I can test each selection is functioning.

two questions:
1. does anyone have a wiring diagram for this machine
2. does anyone have a rotary switch.

TIA.

 

[eddie49]

The welding output failing on the "odd" switch settings but still working on the "even" positions does sound like an internal fault in the 6-way rotary switch. As you have unfortunately already found, the usual advice in the Forum is to never try to take these switches apart!

Often these rotary switches are simple 1-pole x-way, but this one is not so easy. It is basically a 1-pole 2-way coupled with a 1-pole 3 way, so that the 2-way section selects "Low" or "High" ranges, and then there are 3 power choices in each of the two ranges.

Apparently the Einhell SGA products are originally Italian Telwin machines, and were also sold with Sealey branding. I have found a German website with a thread about the SGA 165, and in Post #4 there is a circuit diagram for the model 175, which is probably very similar:

Einhell SGA 165

Hallo habe ein altes schweißgerät Einhell SGA 165 Das Gerät hat immer Strom auf dem Brenner. Es ist kein Schütze eingebaut. Nun meine Frage kann man einen Schütze nachträglich einbauen ?

www.werkzeug-news.de

That diagram includes a very useful "Truth Table" for the rotary switch.
If there is an equivalent Sealey machine that would be good news, because Sealey normally provide good spares support. I will try to find more info.
In the meantime, Forum member @Nix2 will most likely be able to help you.....

 

[dieselman]

Thanks for that, I've had a look.
As far as I can see that machine has 5 cables leading into the transformer, whereas my machine has 8 cables (4 pairs).
I understand about the switch selecting low and high output ranges, then selecting each transformer input coil to give the respective output.

I understand the truth table, but need to work out the transformer coil connections. If I can get to that point I should be able to sort a switch/switches.

I foolishly only took one image of the switch connections. The very left bank is the secondary transformer and consumer 240v feed, the other three switches are the main transformer coils.

As on that diagram I do have a separate 24v transformer to drive the consumers.
Interestingly, when I first bought the machine it had had a Euro torch fitted, which had the wire live all the time. The torch trigger had been wired up to the permanent live 24v supply, not the switched one.

 

[eddie49]

Due to the "inverse" output voltage vs. turns ratio of transformers, the largest number of turns on the primary will produce the lowest output voltage on the secondary - i.e. the Position 1 setting. This will also be the highest resistance for the primary coil, but actually probably only 2 Ohms or less. At each subsequent switch position, the number of turns will decrease, the output voltage will increase, and the primary resistance will decrease. This will be in roughly-equal steps, such as 2.0, 1.8, 1.6, 1.4 Ohms, etc.
In Position 0, everything is Off.
In Position 1, A1 and A2 join to 6 and 7 to feed the auxiliary 24v transformer, and this applies to all subsequent steps too.
In Position 1, L1 joins to 1 and L2 connects to 5. These are the two extreme outer ends of the primary of the main transformer, so I guess that "1" is the "MIN" range and "5" is the lowest output power.
Then in Position 2, L1 goes to 2 and L2 stays on 5. This would be "MAX" and "5".
And so on for all the rest of the positions.

In your machine, the "odd" numbers have failed, so either the "L1" pole of the switch cannot connect in Positions 1, 3, and 5, or possibly the "MIN" transformer tapping or winding has broken off or failed.

Based on that diagram for the Model 175, the start of the transformer primary, i.e. the "1" cable, will be a single solid wire in a sleeve. The first tapping, i.e. "2", will typically be two solid wires in one sleeve, one coming out from the transformer to the switch, and the other returning to the bobbin. The wire may be left intact and cleared of insulation, or cut and then both wires joined back together at the tag or screw terminal. This also applies to the next two tappings, and then the 8th and final wire will just be a single wire.