Download Induction motor nameplate

Contactor
• A contactor is a relay with heavy-duty
contacts to carry large amounts of current.
• Available either Normally Open or
Normally Closed
Norm allyOpenContactor
1
Full-Voltage Starting
S1
1
V1
S4
3PH_MOTOR
T1
S2
T2
3PH
M
120 V 60 Hz
Line Terminals
1
T3
S3
Motor Terminals
1
Contactors S1, S2, S3
Autotransformer Starting
Run1
1
Start1
1
T1
AUTO_XFORMER
Start4
1
S4
3PH_MOTOR
Run2
V1
M
1
3PH
Start2
120 V 60 Hz
1
Run3
T2
AUTO_XFORMER
1
Start5
1
Start3
1
T3
AUTO_XFORMER
Autotransformer Starting (continued)
• To Start
– All S contacts CLOSE
– Line terminals connect
to high-side of
autotransformers.
Low-sides of
autotransformers are
connected together.
• Taps of
autotransformers are
connected to the
motor terminals
providing lower than
line voltage for
starting.
Run1
1
Start1
1
T1
AUTO_XFORMER
Start4
1
S4
3PH_MOTOR
Run2
V1
M
1
3PH
Start2
120 V 60 Hz
1
Run3
T2
AUTO_XFORMER
1
Start5
1
Start3
1
T3
AUTO_XFORMER
Autotransformer Starting (continued)
• When motor reaches
near-rated speed, S
contacts are OPENed
and the R contacts
are CLOSED.
• Full voltage is now
applied to the motor
terminals.
Run1
1
Start1
1
T1
AUTO_XFORMER
Start4
1
S4
3PH_MOTOR
Run2
V1
M
1
3PH
Start2
120 V 60 Hz
1
Run3
T2
AUTO_XFORMER
1
Start5
1
Start3
1
T3
AUTO_XFORMER
Series Impedance Starting
Run1
1
Start1
Z1
Z=A+jB
1
Run2
1
V1
Start2
3PH
120 V 60 Hz
Z2
Z=A+jB
1
Run3
1
Start3
Z3
Z=A+jB
1
S4
3PH_MOTOR
M
Series Impedance Starting
• Close S contacts at
Start
• Open S contacts and
close R contacts at
Run
• Apply approximately
70% of rated voltage
to start
• Z is usually either
Inductive or Resistive
Run1
1
Start1
Z1
Z=A+jB
1
Run2
1
V1
Start2
3PH
120 V 60 Hz
Z2
Z=A+jB
1
Run3
1
Start3
Z3
Z=A+jB
1
S4
3PH_MOTOR
M