Main Injector Hipot

Extended

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Before turning off for, and back on from, any accesses into the Main Injector enclosures (either MI-10 or MI20-62) it is necessary to perform a Hipot of the Main Bus and Power supplies to document present ground currents and to ensure that no ground faults were created during the access. This document explains the correct procedure for Hipotting the Main Injector.

With an ESS for the tunnel and with all locks off of the MI-10 and MI20-62 lock boxes:

Perform a Bus & PS Hipot on the Bend, QF, and QD buses in Lower & Upper to Ground mode.

  1. Set up I17 and select Bus & PS, Bend, QF, and QD and Lower & Upper to Ground (P1)
  2. Unlock and Turn on the Hipot Power Supply
  3. Slowly increase hipot voltage to -1000V (-1kV) and observe the hipotter current
  4. If the hipot current exceeds 50mA at any point there is a Ground Fault. Perform additional diagnosis to determine the source of the ground fault and clear it.
    • In this mode the plot and analysis are of little use in detecting the location of a ground fault. The magnitude hipot current is the best indicator of the presence of a ground fault.
  5. Log the Hipot voltage and current
  6. Turn down the hipotter to 0V

Perform a Bus Only Hipot on the Bend and QF buses in Lower to Upper Ground mode.

  1. Set up I17 and select Bus Only, Bend, QF, and Lower to Upper Ground (P2)
    • The QD bus must be deselected
  2. Unlock and Turn on the Hipot Power Supply
  3. Slowly increase hipot voltage to -1000V (-1kV) and observe the hipotter current and hipot graphics
  4. If any voltage taps on the QD and Upper (the grounded buses) rise above 0V at any point on the graph, there is a bus to bus short. Determine the sourece of the ground fault and clear it.
    • In this mode dips on the hipotted buses (Lower and QF) indicate the location of any other faults, soft or hard.
  5. Perform a hipot analysis and log it and the hipot graphics
  6. Turn down the hipotter to 0V

Perform a Bus Only Hipot on the Bend and QD buses in Upper to Lower Ground mode.

  1. Set up I17 and select Bus Only, Bend, QD, and Upper to Ground (P3)
    • The QF bus must be deselected
  2. Unlock and Turn on the Hipot Power Supply
  3. Slowly increase hipot voltage to -1000V (-1kV) and observe the hipotter current and hipot graphics
  4. If any voltage taps on the Lower and QF (the grounded buses) rise above 0V at any point on the graph, there is a bus to bus short. Determine the sourece of the ground fault and clear it.
    • In this mode dips on the hipotted buses (Upper and QD) indicate the location of any other faults, soft or hard.
  5. Perform a hipot analysis and log it and the hipot graphics
  6. Turn down the hipotter to 0V