# What should be the power rating of the StepDown Transformer?

1. Feb 20, 2016

### Yam

Dear Forum Members,

I imported an electrical equipment from the US which uses 110v, my country used 220v and as such i need to pirchase a step down transformer.

The equipment is a piece of antique and doesnt come with much instructions. I could only get a circuit diagram and i am puzzled by what is VAL. Could anyone help me out?

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2. Feb 20, 2016

### drvrm

As i saw your circuit its a one step -down transformer such that if you input 240 volts it can give an output of 115 volts - naturally the number of turns in the primary and secondary have been adjusted to give this output . i could only that VAL. refers to the value of the voltage -there is no restriction on current given - but before using it one should check by a multimeter the real output voltage with a main line input-just to be on safe side- if the equipment is very heavy say 10 kg or so then it may be rugged one and can withstand higher load-that is my guess!

3. Feb 20, 2016

### anorlunda

Any answer to your question must begin with the power demand of your as antique device, plus a safety margin such as 2:1.

4. Feb 20, 2016

### Yam

I cant seem to find any information of the power demand of this equipment, its actually a large antique chemical photobooth.

Ill do my best to search for the power demand

5. Feb 20, 2016

### Yam

After getting a multimeter, is there anyway i can measure the current without cutting the electrical cables?

I have the circuit diagram of the entire system, would it help if i uploaded it? not too sure if i am allowed to do so or not too.

6. Feb 20, 2016

### anorlunda

Yes, a clamp on type amp meter can measure current without breaking the circuit. Just make sure that it is clamped on only one of the two conductors to the wall plug.

A circuit diagram will probably not help.

If it is plugged in and working now, what is the fuse/circuit breaker rating of the circuit it is plugged in to?

Last edited: Feb 20, 2016