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How to test a Thyristor module ?

Discussion in 'General Electronics Discussion' started by Brad-TN, Nov 21, 2012.

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  1. Brad-TN


    Jan 27, 2010
    Hi. I'm trying to fix a Panasonic MIG welder that hums and throws the breaker when powered on. I've removed and checked the transformer, and believe it to be OK. The next thing in line is the Thyristor module Sanrex PWB130A30 non-isolated type that is mounted to a heat sink. The on line spec sheet for this module seems to say that the gate trigger voltage needs to be less than 2 volts while the on state voltage needs to be at least 1.2 volts. I was wondering if I could test this with a 1.5 volt battery or if I should use a 9 volt battery and use a resistor to get the max gate voltage below 2 volts. I want to get a trust worthy test without damaging the module(of course), if it's still good. I'm an amateur at electronics wondering how you pro's would do this. Thanks.

    Attached Files:

  2. rob_croxford


    Aug 3, 2010
    Use a DMM and set it to measure resistance.
    Measure using the possitive lead connected to the Anode and the negative lead connected to the cathode. The meter should read an infinate resistance (this is good)

    Now short out the gate and the Anode and measure again accross the Anode and the Cathode. The reading should be a low resistance if the device is good.

    Make sure you remove the device from the circuit before running tests.
    Last edited: Nov 21, 2012
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