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Products => Test Equipment => Topic started by: puterboy on October 12, 2020, 02:14:37 pm

Title: Adjustable current limiter for AC line voltage device testing
Post by: puterboy on October 12, 2020, 02:14:37 pm
I would like to add an adjustable A.C. current limiter upstream of my DUT.
I know that a simple solution some people use is to wire an incandescent bulb in series but this is not really adjustable unless you have multiple bulbs, etc.

I was wondering if there is a simple active circuit, perhaps using IGBT's or TRIACs to shut off the circuit based either on voltage across a sense resistor either in series with the circuit or maybe better in an inductive sense loop created by a couple of turns around the voltage line.

Ideally, the current limit would be settable with a potentiometer, bonus if there is a digital display of the limiting current...

I could probably hack together some type of circuit, but was hoping to see if anyone has any simple or off-the-shelf examples.

Any thoughts?
Title: Re: Adjustable current limiter for AC line voltage device testing
Post by: rvalente on October 12, 2020, 04:49:30 pm
What is the voltage/current you're aiming for?

I'm aware you've said lamps does not seems to be a choice but, you can arrange 4 to 6 lamps and combine them in various orders, like: 1-2-4-8-16 or 1-2-5-10 or even 1+1+1+1+2+2 this would give you a certain flexibility + a low cost 1KVA variac is a good way to go.

Chroma makes very nice AC power supplies, maybe some 2nd hand unit?
Title: Re: Adjustable current limiter for AC line voltage device testing
Post by: David Hess on October 13, 2020, 07:41:19 am
I would like to add an adjustable A.C. current limiter upstream of my DUT.

Unless an electronic circuit breaker is acceptable, it comes down to a 2-terminal power current limiter inside of a bridge rectifier which presents some difficulty at typical AC voltages and power levels.