12
228-1692 REV 3
112113
KEPCO, INC.
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131-38 SANFORD AVENUE
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FLUSHING, NY. 11355 U.S.A.
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TEL (718) 461-7000
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FAX (718) 767-1102
http://www.kepcopower.com
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email: [email protected]
DETERMINING HOW THE UNIT RESPONDS
WHEN OUTPUT IS OFF (LOAD TYPE)
The
BOP supports three Load Type selections (see
Table 5) which determine how the power supply
responds when the output is off: ACTIVE, RESIS-
TIVE and BATTERY. The Load Type selection does
not affect the settings of the power supply for ON
state; it only affects the main internal reference level
and the protection levels during the OFF state.
WARNING
For inductive loads, and especially
superconducting magnet type
loads, the inherent offset of the
BOP in the OFF state may generate
significant 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 install-
ing 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 5 indicates how the power sup-
ply 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 volt-
age, current protect and voltage limit are restored.
WARNING
For both inductive loads and con-
stant-current-type active electronic
loads when the BOP output is set
to OFF, a path is provided for
absorbing either the energy accu-
mulated 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 pro-
viding safety for the user. However,
In addition to the built-in safety fea-
tures, constant-current-type active
electronic loads must be adjusted
to zero and the BOP front panel
LCD must read 0V, minimum cur-
rent, before handling the power
supply-to-load connections.
TABLE 5. POWER SUPPLY BEHAVIOR WHEN OUTPUT IS SET TO OFF
LOAD TYPE
SETTING
If unit was in Voltage Mode when output OFF
command issued.
If unit was in Current Mode when output OFF
command issued.
ACTIVE
• Unit remains in voltage mode.
• Voltage set to zero.
• Both ± Current Protect set to maximum.
• Both ± Voltage Limit remain at maximum.
• Unit set to voltage mode.
• Voltage set to zero.
• Both ± Current Protect remain at maximum.
• Both ± Voltage Limit set to maximum.
RESISTIVE
• Unit remains in voltage mode.
• Voltage set to zero.
• Both ± Current Protect set to minimum box values.
• Both ± Voltage Limit. remain at maximum.
• Unit remains in current mode.
• Current set to zero.
• Both ± Current Protect set to minimum box values.
• Both ± Voltage Limit set to maximum,
BATTERY
• Unit set to current mode.
• Current set to zero.
• Both ± Voltage Protect. remain at maximum.
• Both ± Current Limit set to maximum.
• Unit remains in current mode,
• Current set to zero.
• Both ± Voltage Protect set to maximum.
• Both ± Current Limit remain at maximum.
