GASKET 2N7174 - Caterpillar

The field coils are used to generate magnetic fields in the flywheel. This procedure should be done whenever the APC board or the Field Coil Driver (FCD) board are replaced.
Table 1
Calibration Error Limits    
Parameter     Nominal Target     Percent Deviation    
Flywheel Field Currents, full scale     15 A     1.0 %    
Table 2
Calibration Error Limits    
Parameter     Nominal Target     Total Deviation    
Flywheel Field Currents, no current     0 V     0.15 A    Perform the following steps in order to calibrate the field coil current for Flywheel A and Flywheel B.
Place the keyswitch of the Flywheel cabinet in the "Spindown/Offline" position.
Connect a PC to the UPS according to the instructions in Testing and Adjusting, "Personal Computer to UPS Connection".
Place the system in the Bypass mode. Refer to Testing and Adjusting, "Transfer to Bypass Mode".
Ensure that the RPM of the flywheel is zero (0).
Open the Flywheel cabinet.
Confirm that the green LED (3) is illuminated for the DC disconnect status before closing the disconnect switch.
Failure to wait for the green LED can cause fuses to blow when the switch is closed.
Illustration 1 g01308950
Flywheel Disconnect Switch and Field Coil Swing Out Panel (1) Field Coil Swing Out Panel (2) DC Disconnect Switch (3) Status/Test Lights (Press to test)
Close the disconnect switch (2) .
Open the field coil swing out panel (1) .
Clamp the probe onto the top field coil lead (TFC +) (5) on the Field Coil Driver board of Flywheel A. Note: The probe must be clamped onto the field coil lead and the probe must be correctly oriented to the direction of current. There is an arrow with reference symbols on the probe clamp. Orient the probe so that the arrow points in the direction of the current.
Illustration 2 g01308967
3000 Amp Current Probe Clamp which is Used for Field Coil Calibration
Illustration 3 g01308969
Flywheel Field Coil Driver Boards (4) Attach Probe Here for BFC + (5) Attach Probe Here for TFC + (6) Flywheel B Field Coil Driver board (7) Flywheel A Field Coil Driver board
Set the meter to measure DC millivolts.
Zero out the multimeter by adjusting the probe Zero Adjustment (9) .
Illustration 4 g01308978
Field Coil Probe Adjustment (8) Probe Settings (9) Zero Adjustment
Properly adjust the probe Settings (8) in order to measure 20 amp.
Ensure that the keyswitch for the Flywheel is turned to the "spindown" position. Refer to illustration 5.
Illustration 5 g01308979
Keyswitch in the "Spindown" position
Place the UPS on-line via the GUI touchscreen.
Open the "Commands" drop-down menu.
Select "Command Group 1:Enter Shutdown Mode" from the "Commands" drop-down menu.The "Command Group 1:Enter Shutdown Mode" menu appears.
Select "Enter Shutdown Mode" from the "Command Group 1:Enter Shutdown Mode" menu.
Illustration 6 g01308986
Enter Shutdown Mode.
Open the "Calibrate" drop-down menu.
Select "A: Field Coil Currents" from the "Calibrate" drop-down menu.
Illustration 7 g01308987
A: Field Coil Currents
Click the "Use Defaults" button.
Enter the minimum field coil current value which is shown on the multimeter.
Illustration 8 g01308988
Calibration of a Channel - A: Top Field Coil Current Minimum Value
Click the "OK" button.The system switches to Maximum and the Current