KEPCO BOP 1KW-MG Operator Manual, Firmware Ver.2.01 to 2.37 User Manual

Page 79

BOP HIPWR 022108

3-19

For inductive loads, and especially superconducting magnet type

loads, the inherent offset of the BOP in the OFF state may generate sig-

nificant current in the circuit. A properly rated switch in parallel with a

resistor must be connected between the power supply and the load.

The switch must be open and the BOP front panel LCD must read 0V,

0A before removing or installing connections between BOP and load.

ACTIVE.

Active mode (default setting) is necessary for the power supply to function properly

and safely with inductive loads and constant-current-type active electronic loads. Active mode
can also be used with resistive loads. Table 3-6 indicates how the power supply responds to a
command to go from Output ON to OFF. When the output is disabled, the unit is set to voltage
mode, voltage is set to zero and both current protect and voltage limit are set to maximum.
When the unit is enabled, the pre-existing settings for voltage, current protect and voltage limit
are restored.

For both inductive loads and constant-current-type active electronic

loads when the BOP output is set to OFF, a path is provided for absorb-

ing either the energy accumulated in the reactance of the load during

the ON state, or energy delivered by an electronic load. This prevents

damage to the load and power supply as well as providing safety for

the user. However, In addition to the built-in safety features, constant-

current-type active electronic loads must be adjusted to zero and the

BOP front panel LCD must read 0V, minimum current, before handling

the power supply-to-load connections.

RESISTIVE.

This mode, as the name suggests, is useful for resistive loads. Table 3-6 indicates

how the power supply responds to a command to go from Output ON to OFF.

Accessing the BOP after the output is disabled in BATTERY mode is

hazardous because (1) high current arcing is possible and (2) either the

external battery voltage, or the voltage (±Voltage Protection max) on

the BOP output terminals may be dangerous. Therefore, for battery and

constant-voltage-type active electronic loads it is recommended that

two properly rated external switches be installed for safety: one in

series with the battery, and one across the BOP output. After the unit is

set to OFF, first open the switch is series with the battery, then close

the switch across the BOP output to ensure safety before handling

BOP connections. When connecting the battery, the switch across the

output should be opened after the connections are complete and then

the switch in series with the battery should be closed. If the constant-

voltage-type active electronic load is adjusted to zero before handling

the power supply-to-load connections, only the switch across the BOP

output is required.

WARNING