Tandem

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Background

Herein should be a general intro to Van de Graaffs, some history of High Voltage Engineering and some specifics about ours. sources, negative ion sources and our source. A set of links should include one to National Electrostatic Corporations page on their Pelletron.

Operation

This section has been written. We'll find it .... Here is a brief version.

Interlocks

The Tandem drive motor is interlocked to several systems to prevent danger to operators and equipment. These are all satisfied under normal conditions; one usually finds a problem when the interlock acts by preventing the Drive Motor from starting. They include

  • a flow switch on the Cooling Water to the coils inside the High Energy end;
  • switches on each of the 4 access ports;
  • relays in the Low and High Energy Vacuum gauges; these are set to ~5 x 10(-6) Torr

Starting the Drive Motor

  • Go to the High Energy end of the tandem
  • Ensure that the High Energy vacuum is ~1 x 10(-7) Torr and that the Laddertron tension is ~900 lbs
  • Plug in the start switch. "Jog" the belt by pressing Start and then quickly pressing Stop. Ensure that the AC Monitor responds, the Vibration Monitor responds, the Tension Monitor briefly shows lower tension and that the sound of the belt is ... right.
  • Start the Drive Motor again. The sound should go up in pitch, stabilize and have a 1 Hz hum. The AC Monitor should show ~118 Vac on all three phases. The Vibration Monitor should show ~1.5 units (the units are actually mm/sec). The tension should fall to ~600lbs.
  • If any of the above values are far from nominal, please seek assistance.

Taking the Tandem to Voltage

At present, raising and setting the Tandem voltage involves a mixture of analog controls and the Master Control program in LabView. Proceed to the Control Room and you will learn the latest version.


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