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Registered Member #1160
Joined: Fri Dec 07 2007, 04:25AM
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Posts: 1
I am working on Development of high voltage high power electron guns for thermal applications. My 60 kV 200 kW electron gun, operates at 4 x 10^-6 mbar pressure. I find sparks jumping from the High voltage leads even after one or two hours of continuus operation of the gun. The high voltage lead is made of ETP grade copper. Can anyone help me please to resolve this issue. How do I ensure reliable long term operation ( 200 hrs) of high voltage electron devices Thanks, swamy
Registered Member #1127
Joined: Mon Nov 19 2007, 12:08AM
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Posts: 139
Using flash over suppressors can insure less sparking... sometimes oiling the surface of the glass can help take off conductive dust --- the oil itself acts as an insulator...
Registered Member #1064
Joined: Tue Oct 16 2007, 05:04PM
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Posts: 42
Arcs in a vacuum produce unbelievable transients. Power supply has to be built like a tank. Transformer has to have shields connected to the ends of the windings to distribute transient voltages throughout the transformer. Otherwise, the transformer will fail a few turns from the start or end of the winding. Transient surge suppressors should be connected across each leg of the rectifier. The diodes should be rated at a minimum of 2.5 times the peak reverse operating voltage and preferably 3 times the operating voltage. Capacitors should be placed across the primary of the rectifier transformer. Transformer should be tested at twice the operating voltage for maybe 60 seconds.
Sparks, Get rid of any sharp edges. Round all edges. In oil and probably in vacuum, charges collect on some insulators. Insulators should insulate enough that they don't draw significant current. Insulators should also have low enough resistance that they don't allow a charge to build up. Tests are probably the best way to determine what works and what doesn't work.
Normally the power supply should have low energy storage to prevent damaging arcs, it should also have low ripple. This means that either a switching power supply or a three phase power should be used.
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High Voltage Vacuum breakdown
