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buggies · 11th Sep 2018, 2:49 pm

I have three useful devices for working on live gear: isolating transformer, variac and lamp-limiter.
Each has a 13A plug and socket so can be used individually or any combination chained in series.
The tip? If using a variac and a lamp-limiter together, ensure the plugs and sockets are connected so that the lamp-limiter is nearest the device under test.
I got my plugs mixed when powering up a suspect SMPS and had a little puff of smoke from my current meter as I wound up the variac from zero (no limiter glow).
Only 4 volts required to put 200mA through a low resistance test load in that configuration instead 65 volts with the variac -> limiter arrangement.
Obvious?

11th Sep 2018, 2:49 pm	#1
buggies Heptode Join Date: Jan 2009 Location: West Lothian, UK. Posts: 761	Lamp limiter plus Variac tip I have three useful devices for working on live gear: isolating transformer, variac and lamp-limiter. Each has a 13A plug and socket so can be used individually or any combination chained in series. The tip? If using a variac and a lamp-limiter together, ensure the plugs and sockets are connected so that the lamp-limiter is nearest the device under test. I got my plugs mixed when powering up a suspect SMPS and had a little puff of smoke from my current meter as I wound up the variac from zero (no limiter glow). Only 4 volts required to put 200mA through a low resistance test load in that configuration instead 65 volts with the variac -> limiter arrangement. Obvious? Attached Thumbnails __________________ George