Zenith variac

[singlepentode69]

The panel on mine looks exactly the same I will have abetter look at mine in a few days time . I am hoping not to blew it up
Regards
Robin

[AlanBeckett]

Never mind it, just don't blow yourself up.

Alan

[singlepentode69]

I will try not to Alan

[Mark Hennessy]

An obvious thought occurs to me while reading through this: if you are in any way unsure about wiring this up, then do it via a lamp limiter. This will protect your variac, and you. Simples

You may already have one. If not, it's definitely worth putting one together. Once your variac is correctly wired and working, you can use it on the output of the variac for all sorts of uses.

Example here: http://www.vintage-radio.com/projects/lamp-limiter.html

I'll admit that when I made my variac, I had a few troubles, and that cost me a few 3A mains fuses (luckily nothing more serious). In my case, it was insulation being breached by the terminals of the mains switch being too close to the input terminals. Dead easy to sort once I'd realised, but confusing at first!

[pwdrive]

http://www.bunkerofdoom.com/adjavolt/index.html

This one is a different make but you can see from the pictures that the terminals either end of the engraved white line are common to each other and are the neutral in/out terminals.

Lawrence.

[singlepentode69]

Thankyou mark I have a lamp limiter I built this a while back when I first started working on valve gear I have seen the mess electrolitic capacitors made at the ceilings at quad.Below is a picture of my test board for testing varios electrical goods with old stye plugs on another one of my collection .I will also use my safe block to test it with
Regards
Robon

[singlepentode69]

Plug board

[Nick]

A while back I built a control panel for testing HV kit (I build big Tesla coils and other HV stuff).

Apart from a stonking 1:1 isolation transformer, I built a Variac control board- schematic in the PDF download - it provides a simple and safe controlled environment to test all sorts of kit with

   

Note the voltage recalibration - we are way out in the country and our mains input regularly exceeds 255VAC - I have on-line UPS systems for all delicate kit to stop the inevitable over-voltage, under-voltage, black-out & brown-out conditions - about one every two days - the UPS systems continually monitor the mains quality and email me if there are out-of-band conditions.

BTW. The isolation transformer is an ex-medical unit - they are very very neat and available on eBay - from my point of view, an excellent investment - I couldn't make one cheaper or better - mine is a ISB-100W (1KW) Medical Isolation Transformer - lovely bit of kit - not very big - essentially a well-insulated toroidal transformer in a box... smaller sizes are available - the IsoBox ISB-030W (300W) is much smaller and probably completely adequate for most workbenches...

EDIT: I have a lamp-limiter too - a couple of 40W incandescent bulbs in batten holders which can be switched in and out but the Variac board is the one that gets the most use.

[singlepentode69]

Very good set up I will probable get it set up like that lots of ideas going through my head just need to wire it up
In the next few days
Regards
Robin

[singlepentode69]

Thanks for your help all up and running and a cheap buy . Now just need to get an isolation transformer another peice of essential kit in the workshop .
Regards
Robin