Trane Starters Engineering Bulletin page 19

Figure 7.
F
F
Starting sequence
1. The "start" signal from the CenTraVac controller energizes the pilot relay (PR).
2. The PR contacts close to energize the star contactor (S).
3. The S contacts close to connect the motor in the star configuration.
4. An S interlock closes to energize the start contactor (1M).
5. The 1M contacts close to connect the motor to the line.
6. A time delay relay or current monitoring device initiates transition by energizing the resistor
7. 1A contacts close to connect the resistors to the line in the star configuration and in parallel with
8. A 1A interlock now opens to de-energize the S contactor.
9. The S contacts open to connect the resistors and motor windings in series in the delta
10. An S interlock closes to energize the run contactor (2M).
11. The 2M contacts close to bypass the resistors and connect the compressor motor directly to the
Dimensions
The typical unit-mounted wye-delta starter size is shown in
mounted one-, two- and three-door starter sizes are shown in
Figure 12, p.
CTV-PRB004-EN
Simplified wye-delta wiring schematic
LINE
VOLTAGE
1M
OL
2M
OL
1M
2M
OL
1M
2M
CPT
START-
STOP
PR 1A 2M
S
S
1M
TRANSITION
contactor (1A).
the compressor motor.
configuration.
line in the delta configuration.
21. Always consult the submittal drawings for as-built dimensions.
WYE-DELTA
STARTER WIRING
R 1A
S
R 1A
S
R 1A
S
PR
S
1M
2M
1A
Low-Voltage Starter Types
MOTOR
Figure 9, p. 20.Typical remote-
Figure 10, p. 20, Figure 11, p. 20, and
19