General Electric Variac wiring help

Hi All!
My brother got this variac from someone. We stay in South Africa where our voltage is 220V. Could someone perhaps help with hooking this baby up..
I don't know where to connect the 220V. Couldn't find anything on the net either.
See attached pic.
Much appreciated.

Connect the mains input to 1 (neutral) and 4 (live).

Then take a variable output from 1 (neutral) and 3 (variable voltage live).

This assumes that 1 is connected to the anti-clockwise end of the core and that 4 is connected to the clockwise end of the core.

At the risk of boring you with the safety info, please be aware that a variac on its own does not provide isolation from the mains.
(If you are not aware already).

JimB

On edit:

Having studied the picture a bit more (and turned it the right way up!), that variac has an overwind so that you can get up to 280volts from it.
Without measuring, (and this is inspired guess work) the terminals should be:

Terminal 1 0v (neutral)
Terminal 5 110v
Terminal 6 120v
Terminal 7 220v
Terminal 2 240v
Terminal 8 280v
Terminal 3 variable

I suggest that you start off with it connected as I originally suggested with neutral on 1 and live on 4.
Then measure the voltage between 1 and 7, assuming the mains is 220v and if my theory is correct you should see about 173 volts.
If that works out, reconnect the live to terminal 7 and you should now have an output variable from 0 to 280 volts.

JimB

I would only add to Jim's fine post that since you have an open frame unit it would be advisable to fuse it. I would go with likely a 5 amp fuse on the mains high side.

Ron

Also I suggest that you measure the current that the variac takes with no load. It should be less than about 100 mA. It will be a lot more if you connect the 220 V supply to a connection that is designed for a lower voltage.

If you put a 500 W floodlight in series, that will protect against shorts, as the floodlight will just light if there is a short. You can remove it when you are sure that it works OK.

Another boring safety suggestion. Plug the variac into a GFC type outlet. That will protect you from accidental shocks to ground while working on the unit and releasing the magic smoke from your ears.

Reloadron:

Best practices say to fuse the wiper, not the input to the transformer in the long term. In the test phase, yes fuse the input.

The reason to fuse the wiper is that it's really easy to exceed the wire carrying capacity of wiper and not exceed the core wattage.

There is no harm in fusing both.

hi diy,
The nominal mains voltage in South Africa is 230Vac 50Hz, not 220Vac.

I would connect as JimB suggested, via a fused mains connector, IIRC in RSA most houses have RCD/GFC earth detectors on the incoming distribution panel.

Fuse the wiper like these manufacturer drawings recommend: https://www.electro-tech-online.com/custompdfs/2012/05/5011.pdf

I agree, fuse the output wiper. My bad.

Ron