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pole pig
Posted by Jeffrey Bull on 3/27/2004, 10:28 pm
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Re: pole pig
Posted by Bert Hickman on 3/28/2004, 12:17 am, in reply to "pole pig" Hi Jeffrey, NO - that's not correct. You normally do not use the center lug. However, I need a bit more clarification of exactly what you have for power coming into the pig before I can answer your questions. First: Second: Third: The tap setting usually for minor voltage changes and it's position should not be relevant to the proper operation of the pig. I assume you have had some prior HV experience such as working with NST's before tackling this. Be very careful - you will not get a second chance if you have a HV accident with this transformer. -- Bert --
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Re: pole pig
Posted by Jeffrey Bull on 3/28/2004, 10:42 am, in reply to "Re: pole pig" --Previous Message--
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Re: pole pig
Posted by Bert Hickman on 4/1/2004, 10:04 am, in reply to "Re: pole pig" Hi Jeff, Sorry for the delay in responding, and thanks for providing the additional details on your system. It sounds like you've got the pig hooked up properly - one side of the mains to X1 and the other side (through the variac and ballast inductor) to X3. X2 (the middle LV lug) should not be connected to anything. The transformer can should be connected to mains earth. However, first make sure that the center lug (X2) is NOT also electrically connected to the case via an internal strap. If it is, you'll need to pop the lid on the transformer and disconnect the strap connecting X2 to the can. It sounds like your voltmeter is correctly hooked up across the LV input to the pig. With the HV side of the transformer open circuited, does the voltmeter seem to track the incoming voltage properly as you ramp up the voltage? If the voltage stays low and you also begin to pull significant current through the ballast, you may have a short circuited transformer. You'll need to remove the lid of the transformer to see if there are any obvious signs of damage. A shorted transformer will most likely require rewinding. If the above test passed, kill power and short circuit the pig's HV output. Then power up again and carefully begin to increase the voltage with the variac - are you now pulling current through the transformer's LV winding? You should see the current rise fairly linearly as you increase the voltage to the pig. The voltage across X1 and X3 will stay at about 0 volts during this test. If this does not occur, you may have an open primary, an open secondary, or a defective tap switch. In this case, you'll need to disconnect the pig and, using an ohmmeter or continuity checker, verify continuity across the primary and secondary windings. Note: the secondary may be a bit difficult to accurately measure with an ohmmeter due to the high inductance of the winding - all you are looking for is continuity. An open on either the primary or secondary side will require that you pop the lid on the transformer can to see if there are any connections that have come undone or if there is any other obvious internal damage to the pig. -- Bert --
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