Thermo King UT-1200, Manual

Page: 85 / 169

Electrical Maintenance
85
If phase orientation is L1, L2, L3 the 7EB wire
will output voltage to energize the appropriate
phase rotation contactor MCA. If phase
orientation is L1, L3, L2 the 7EC wire will output
voltage to energize the appropriate phase rotation
contactor MCB. The 7EB and 7EC wires are
interlocked to prevent both phase contactors from
being energized at once.
If the SP input is grounded, the module will now
be set for single-phase operation. In this case only
the Brown and Gray wires are used and the Black
wire is taped off.
Connections to the module are shown in the tables
below.
Removal and Replacement
1. Turn unit off.
2. Disconnect the unit battery.
3. Disconnect the standby power.
4. Remove the high voltage cover.
Power Connections
Input Description
8 Nominal 12 volt DC power to the phase
select module
CH Chassis ground
Inputs
Input Description
L1 This Brown wire supplies standby power L1
to the phase select module.
L2 This Gray wire supplies standby power L2
to the phase select module.
L3 This Black wire supplies standby power L3
to the phase select module.
7EA If 12 volts DC is supplied, then output 7EB
or 7EC will be at 12 volts DC
SP If this wire is connected to chassis ground
the module will operate in single-phase
mode.
SP-
GND This is an internal ground for the module. If
SP-GND is jumpered to SP then the
module will be set to operate on single
phase.
Outputs
Output Description
7EB If phase orientation is L1, L2, L3 then this
wire will provide 12 volts DC to energize
the appropriate phase rotation contactor
MCA. The 7EC wire is interlocked to
prevent both phase contactors from being
energized at once.
7EC If phase orientation is L1, L3, L2 then this
wire will provide 12 volts DC to energize
the appropriate phase rotation contactor
MCB. The 7EB wire is interlocked to
prevent both phase contactors from being
energized at once.
ER This wire will output 12 volts DC to the
microprocessor 2 to 4 seconds after the
voltage rises above 165 volts AC and all
three phases are present. If the voltage
drops below 160 volts AC or a phase is
lost and the condition remains for 3
seconds, the output is turned off. The
module continues to monitor and will
again output 12 volts DC 2 to 4 seconds
after the power returns to normal (voltage
rises above 165 volts AC and all three
phases are present).
Connector Pinout
Pin Wire Description
1 8 Power to Module
2 CH/CHV Chassis ground
3 ER AC Power OK, output to
microprocessor
4 7EA/7E Power for 7EB or 7EC output
5 7EB Output to MCA
6 7EC Output to MCB
7 SP-GND Internal ground to enable a
jumper circuit for SP logic
8 SP Grounded for single phase mode
9 Unused