Thermo King SR-2 SmartReefer2, Diagnostic Manual

Page: 362 / 431

Section 6 – SR-2 Service Procedure A48A
Operation
The brown, blue and black wires are used to sample the power at L1, L2 and L3 respectively. Operating power
from 12 to 24 VDC is supplied to the module via the #8 wire and CH wire.
When the voltage sensed rises above 180 volts AC and all three phases are present the module ER wire will
output 12-24 VDC after the conditions exist for 2 to 4 seconds. This signal informs the microprocessor that
electric standby operation is possible. If the voltage drops below 160 volts AC or a phase is lost, the output is
turned off after the condition exists for 8 to 10 seconds. The module continues to monitor the power and will
again output 12-24 VDC within 2 to 4 seconds after the voltage rises above 180 volts AC and all three phases are
present.
If phase rotation is L1, L2, L3 the 7EB wire will supply 12 to 24 VDC to energize the appropriate phase rotation
contactor. If phase rotation is L1, L3, L2 the 7EC wire will supply a chassis ground to energize the appropriate
phase rotation contactor. The 7EB and 7EC wires are interlocked to prevent both phase contactors from being
energized at once.
Connections
Connections to the module are shown in the tables below.
Power Connections
Input Description
# 8F Supplies nominal 12-24 volt DC power to the phase detect module.
CH Chassis ground
Inputs
Input Description
L1 This brown wire supplies standby power L1 to the phase detect module.
L2 This blue wire supplies standby power L2 to the phase detect module.
L3 This black wire supplies standby power L3 to the phase detect module.
Page 2
P41RA48A 30 January 2005