American Magnetics 12200PS DC Power Supply (CE-Marked) - Manual (Page 38)

LOCAL OPERATION OPERATING MANUAL
3-4 Release 1.0 (98/07)
3.3 Using Over Voltage Protection (OVP)
The OVP circuit protects the load in the event of a remote programming error, an incorrect voltage control
adjustment, or a power supply failure. The protection circuit monitors the output voltage at the output of the
power supply and will shut down the main power converter whenever a preset voltage limit is exceeded. Set the
preset voltage limit (also called the set point or trip level) using the screwdriver-adjustable, front panel OVP
potentiometer, or via one of the optional GPIB or RS-232 programming interfaces.
Notes:
1. The default preset limit is approximately 110% of the rated output voltage.
2. When using OVP with remote sensing lines connected, compensate for the voltage line drop across the
output return line by measuring or calculating the line drop, then adding this value to the desired OVP
setpoint.
3.3.1 Front Panel OVP Operation
In local control mode, check the OVP set point at any time by pressing the OVP CHECK switch. The OVP set
point is the value displayed on the digital voltmeter.
To set the trip level from the front panel:
1. Disconnect any loads. Turn the power supply ON.
2. Adjust the power supply output voltage to any voltage lower than the desired trip level.
3. Press the front panel STANDBY (output shutdown) switch to its IN position. The red S/D LED
turns on.
4. Press the OVP CHECK switch to see the OVP set point on the voltmeter display.
5. Holding down the OVP CHECK switch, turn the OVP SET potentiometer until the desired set point is
reached. Release the OVP CHECK switch.
6. Press the STANDBY switch to its OUT position. The S/D LED turns off.
7. To check that the power supply shuts off at the desired set point, slowly increase the output voltage
while monitoring the front panel voltmeter. The OVP LED on the front panel turns on when the OVP
circuit activates.
3.3.2 Resetting the OVP Circuit
To reset the OVP circuit after it activates:
1. Reduce the power supply's output voltage setting to below the OVP set point.
2. Press the STANDBY switch IN. The red S/D LED on the front panel turns on. The OVP LED
turns off.
3. Press the STANDBY switch again to return power to the load and resume normal operation.
OR
1. Reduce the power supply's output voltage setting to below the OVP set point.
2. Turn the power supply OFF using the AC power switch, wait until the front panel displays go out, then
turn the power supply back ON again.