Reference Information - Lennox HP21 Installation Instructions Manual

Reference Information

UNIT INFORMATION MANUALS
Unit information manuals are available on DaveNet for
both the HS21 and HP21.
1. HS21 Unit Information is CORP 9406−L3.
2. HP21 Unit Information is CORP 9434−L12.
OPERATION SEQUENCE − COMPRESSOR
Single-Phase Compressor Start−Up
1. Figure 8 illustrates windings of a single-phase
two−speed compressor. This compressor has a
two−speed capacitor-start, capacitor-run motor. For
starting, the start and run capacitors are in parallel to
provide the proper starting torque. The start capacitor
is disconnected by the start relay when the
compressor comes up to speed. The run capacitor
remains connected to the start winding and the motor
runs as a two-phase induction motor with improved
power factor and torque characteristics provided by
the capacitor.
SINGLE-PHASE MOTOR WINDINGS LOW SPEED
MOTOR LEAD TERMINALS
RUN WINDINGS
RUN
CAP.
START
CAP.
START RELAY
SINGLE-PHASE MOTOR WINDINGS HIGH SPEED
MOTOR LEAD TERMINALS
RUN
START
CAP.
CAP.
START RELAY
Figure 8. Single−Phase
1
COMMON
2
7
HIGH SPEED
START WINDINGS
3
8
LOW SPEED
START WINDINGS
1
COMMON
2
7
RUN WINDINGS
HIGH SPEED
START WINDINGS
3
8
LOW SPEED
START WINDINGS
2. Low speed compressor operation is provided by
powering the run windings (internally connected in
series) from terminals 1 (common) and 7.
windings form a four-pole motor operating at 1800
RPM. The four low speed start windings are in series
and are connected to terminals 1 (common) and 8.
They are used with the start and run capacitors and
start relay to start and bring the motor up to speed.
3. High speed compressor operation is provided when
the run windings are connected in parallel; terminals
1 (common) and 7 to L1 and terminal 2 to L2. The
windings form a two-pole motor operating at 3600
RPM. The two high−speed start windings are in series
and connected to terminals 1 (common) and 3.
Three−Phase Compressor Start−Up
1. Figure 9 illustrates the windings of three-phase,
two-speed compressors. These compressors are
two-speed, three-phase induction motors. Capacitors
are not needed to provide the proper phase and torque
characteristics.
2. Low speed operation is provided when the motor
windings are connected in a series Delta circuit. The
motor operates at 1800 RPM.
3. High speed operation is provided when the motor
windings are connected in a parallel Delta circuit.
THREE-PHASE MOTOR WINDINGS LOW SPEED
SERIES DELTA" CIRCUIT
L1
L2
L3
THREE-PHASE MOTOR WINDINGS HIGH SPEED
PARALLEL DELTA" CIRCUIT
L1
L2
L3
Page 10
T1
T6 T4
T2
T5
T4 COMPRESSOR
CONTACTOR K226
(Normally open contacts shown
in energized/closed position)
T1 T3
T6 T2
Figure 9. Three−Phase
The
T3
T5