136
FORM 160.54-M1
ISSUE DATE: 10/25/2019
SECTION 13 - SOLID STATE STARTERS
JCI COMPANY CONFIDENTIAL
JOHNSON CONTROLS
lished with the Supply Line Voltage Range setpoint.
Each supply voltage application has an allowable up-
per and lower limit. If the supply voltage goes above
or below these limits continuously for 20 seconds, the
Logic/Trigger Board initiates a cycling shutdown and
displays LCSSS - HIGH SUPPLY LINE VOLTAGE or
LCSSS - LOW SUPPLY LINE VOLTAGE as appro-
priate. The chiller will automatically restart when the
line voltage is within the acceptable range.
While the chiller is running, the microboard will close
or inhibit opening of the Pre-rotation Vanes (PRV),
as required, to limit the compressor motor current to
the Current Limit or Pulldown Demand Limit setpoint
(30% to 100% FLA) that is in effect. The microboard
calculates the “% Full Load Amps” (FLA) by divid-
ing the highest phase of the 3-phase motor current,
received from the Logic/Trigger Board, by the value
programmed for the Full Load Amps setpoint. The
message % FULL LOAD AMPS is displayed on the
MOTOR Screen. If the motor current increases to the
extent that the % FULL LOAD AMPS reaches 100%
of the Current Limit setpoint, the Pre-rotation Vanes
(PRV) are inhibited from further opening until the mo-
tor current decreases to less than or equal to 98% of the
Current Limit setpoint. If the motor current increases
to the extent that the % FULL LOAD AMPS is 104%
of the Current Limit setpoint, the PRV will be driven
closed until the % FULL LOAD AMPS decreases to
102% of the Current Limit setpoint. The PRV opening
will then be inhibited until the % FULL LOAD AMPS
decreases to less than or equal to 98% of the Current
Limit setpoint.
