AMETEK BPS Series - Manual (Page 129)

User Manual AMETEK Programmable Power
BPS Series 129
7.5 Non-Routine Calibration
WARNING: THIS EQUIPMENT GENERATES POTENTIALLY LETHAL
VOLTAGES. DEATH ON CONTACT MAY RESULT IF PERSONNEL FAIL TO OBSERVE
SAFETY PRECAUTIONS. DO NOT TOUCH ELECTRONIC CIRCUITS WHEN POWER IS
APPLIED
The non-routine calibration may involve removing the front or top cover of the power source. Use
extreme caution when performing any of these tasks while the system is connected to AC mains and/or
powered up.
7.5.1 Power Source Gain Adjustment
For any BPS configuration that requires two or more amplifiers to be operated in parallel for increased
current output, the amplifier gains have to matched as closely as possible to ensure equal current sharing.
If an unbalance exists between amplifier outputs, one or the other amplifier will deliver more current and
may run into its current limit protection before full output power can be attained.
This procedure details the gain adjustment. Generally, BPS units are shipped with the gains already set
correctly so this task should only be undertaken if an amplifier has been replaced or if two BPS units are
to be combined that were not originally shipped from the factory as such.
To make this adjustment the front cover must first be removed in order to get access to the power module
output terminals.
If the power system to be adjusted is a BPS150 or BPS180 model, the procedure involves matching the
output voltage of the A, B and C power modules in the master cabinet to the A, B and C power modules in
the auxiliary cabinet. Proceed as follows:
1. Shut off all power to the cabinets. Disconnect the two wires going to Terminal 6 and Terminal 7 on
the lower front of the power modules. Do this to module A, A’, B, B’, C and C’ in the auxiliary
cabinet(s) only. Place some temporary insulation over the lug ends.
2. Connect a DMM between terminals 6 and 7 on the A module in the master cabinet. Power up the
cabinet. Set the controller to the 300V range, program 230V at 60Hz. Enable the output by pressing
the OUTPUT ON/OFF key. Measure the A module output voltage and write it down. Press the
OUTPUT ON/OFF key to disable the output.
3. Move DMM leads to the B module terminals 6 and 7. Press the OUTPUT ON/OFF key to enable the
output. Measure the B module output and write it down, Press the OUTPUT ON/OFF key to disable
the output.
4. Move DMM leads to the C module terminals 6 and 7. Press the OUTPUT ON/OFF key to enable the
output. Measure the C module output and write it down, Press the OUTPUT ON/OFF key to disable
the output.
5. Move the DMM leads to the A module terminals 6 and 7 in the auxiliary cabinet. Press the OUTPUT
ON/OFF key again to enable the output. Verify the phase A module output is within 50mVolts of the
A module in the master cabinet. If it is not, adjust the pot behind the hole in the upper left corner of
the module so the A output matches the A master output within 50mVolts. Repeat for the A’ module.
Press the OUTPUT ON/OFF key to disable the output.
6. Move the DMM leads to the B module terminals 6 and 7 in the auxiliary cabinet. Press the OUTPUT
ON/OFF key again to enable the output. Verify the phase B module output is within 50mVolts of the
B module in the master cabinet. If it is not, adjust the pot behind the hole in the upper left corner of
the module so the B output matches the B master output within 50mVolts. Repeat for the B’ module.
Press the OUTPUT ON/OFF key to disable the output.