Kepco BOP Bipolar Power Supply Troubleshooting and Maintenance Guide

Attention: The above adjustments must be made after sufficient preheating (at least 30 minutes) and ensure stable ambient temperature.

Common problems in master-slave series/parallel configuration

BOP can be connected in series (voltage addition) or in parallel (current addition), and it is recommended to use master-slave control method.

6.1 Uneven or out of control output voltage during series configuration

Possible reason: The grounding network of the slave (SLAVE) is not disconnected. The link (4-5) should be opened on the rear terminal TB201 of SLAVE to isolate the output common terminal of the slave from the chassis. Otherwise, it will cause a grounding loop.

Coupling adaptation resistance RT calculation error: RT (k Ω)=(Eom_max -10), where Eom_max is the rated output voltage of the host. For example, for BOP 100-2M host, RT=100-10=90 k Ω. If the resistance is too small, it will limit the amplitude, and if it is too large, the slave will not be able to follow at full range.

6.2 Uneven current distribution during parallel configuration

Root cause: The slave is not correctly placed in current mode and the current control switch is not turned off. When connecting in parallel, all slave MODE switches must be set to CURRENT, and the CURRENT CON switch must be turned off. The driver signal output from the host is through pin 10 of PC-12 (programming signal for host voltage in voltage mode)? The actual parallel connection should use current mode master-slave connection: from the host PC-12 pin 19 to the slave pin 13? Manual Figure 3-27 clearly states that the host pin 10 (I2) is sent to the slave pin 19. Ensure reliable connection of shielded cables.

Protection measures: All parallel/series BOPs should be interlocked through a "circuit breaker control circuit" (see Figure 3-28). Once a fault occurs in one unit, the SCR triggers the circuit breakers of all units to trip simultaneously, preventing system overvoltage.

Interpretation of indicator lights and status signs

The BOP front panel has five LED status lights:

Eo MODE (green): Voltage mode activated.

Io MODE (green): Current mode activated.

VOLTAGE LIMITED (yellow): The voltage limiting circuit operates (reaching the set upper or lower limit).

Current Limit (yellow): The current limiting circuit is activated.

Remote (blue): Remote control activated (PC-12 pin 35 grounded, or BIT card enabled).

The rear PC-12 provides a corresponding TTL flag (low level valid). If a certain flag logic level is abnormal (such as always low), it is necessary to check the comparator circuit or reference voltage.

Special note: When the GPIB interface card (such as BIT 488) is set to "remote", the front panel MODE switch fails, but the voltage/current limit knob remains valid. To restore local control, disconnect pin 35 of PC-12 from COMMON or set the device back to LOCAL using a command.

Recommendations for spare parts and long-term storage

When not in use for a long time, it should be stored in a dry, dust-free environment at a temperature of -25 ° C to 70 ° C. Every six months, power on and run for 2 hours to maintain the performance of the electrolytic capacitor.

Spare parts suggestion: Keep the original PC-12 connector (jumper for local control), a set of external programming resistors (10k Ω, 100k Ω metal film), and two spare fuses (slow melting type, specifications see manual) provided by the factory.

If you need to change the 200W/400W model to ML version to be compatible with a wide range of inductive loads, please contact Kepco factory for upgrade services.