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Re: Open PT primary?

2/7/2006 3:19 PM
R.G.	Re: Open PT primary? [QUOTE]between each primary end and ground: infinite ohms (=open). This occurs with the two black wires either connected to the circuit or disconnected. In either case the primary ground wire was tied to ground. What is this? The TADP doesn't even mention an open reading between the primary ends![/QUOTE] That may be OK. If there is a "primary ground" lead, it's possibly a shield between primary and secondary. If so, it absolutely should be open between it and the primary leads. If you had an open between the black wires, it certainly would not blow fuses - nothing would happen. Did you test for shorts to frame and to the secondaries? IF you really suspect a short inside the PT, use the shorted transformer tester at GEO, http://geofex.com/FX_images/xform_test.gif With a battery, a neon bulb and a resistor, you can detect any internal shorted turns with one test. The ohmmeter then tells you whether you have an open on any winding, or a short between windings.

2/7/2006 3:19 PM

R.G.

Re: Open PT primary?

[QUOTE]between each primary end and ground: infinite ohms (=open). This occurs with the two black wires either connected to the circuit or disconnected. In either case the primary ground wire was tied to ground.

What is this?
The TADP doesn't even mention an open reading between the primary ends![/QUOTE]
That may be OK. If there is a "primary ground" lead, it's possibly a shield between primary and secondary. If so, it absolutely should be open between it and the primary leads.

If you had an open between the black wires, it certainly would not blow fuses - nothing would happen.

Did you test for shorts to frame and to the secondaries?

IF you really suspect a short inside the PT, use the shorted transformer tester at GEO,
http://geofex.com/FX_images/xform_test.gif

With a battery, a neon bulb and a resistor, you can detect any internal shorted turns with one test. The ohmmeter then tells you whether you have an open on any winding, or a short between windings.

Replies:

Peter Just a thought - its not a 120 volt... -- 2/7/2006 8:44 PM