Rockwell Automation 150 MNL/SMC DIALOG+/APP-PROD GUIDE - Manual (Page 133)

SMC Dialog Plus Controller Special Application Considerations 5-9
Part Winding
Part Winding motors incorporate two separate, parallel windings in
their design. With the traditional part winding starter, one set of
windings is given full line voltage, and the motor draws about 400%
of the motor’s full load current rating. Additionally, about 45% of
locked rotor torque is generated. After a preset interval, the second
winding is brought online in parallel with the first and the moto
develops normal torque.
The part winding motor may be wired to an SMC Dialog Plus
controller by connecting both windings in parallel. Again, the
starting torque can be adjusted to match the load with paramete
programming.
Wound Rotor
Wound Rotor motors require careful consideration when
implementing SMC Dialog Plus controllers. A wound rotor motor
depends on external resistors to develop high starting torque. It may
be possible to develop enough starting torque using the SMC Dialog
Plus controller and a single step of resistors. The resistors are placed
in the rotor circuit until the motor reaches approximately 70% of
synchronous speed. At this point, the resistors are removed from the
secondary by a shorting contactor. Resistor sizing will depend on the
characteristics of the motor used.
Please note that it is not recommended to short the rotor slip rings
during start-up, as starting torque will be greatly reduced, even with
full voltage applied to the motor. The starting torque will be even
further reduced with the SMC Dialog Plus controller since the output
voltage to the motor is reduced on start-up.
Synchronous
Synchronous, brush-type motors differ from standard squirrel cag
motors in the construction of the rotor. The rotor of a synchronous
motor is comprised of two separate windings, a starting winding and a
DC magnetic field winding.
The starting winding is used to accelerate the motor to about 95% of
synchronous speed. Once there, the DC magnetic field winding is
energized to pull the motor up to synchronous speed.
The SMC Dialog Plus controller can be retrofitted to a synchronous
controller by replacing the stator contactor with the SMC Dialog Plus
controller and maintaining the DC field application package.
For technical support in applying the Bulletin 150 SMC Dialog Plus controller to
these special motors, contact your local Allen-Bradley representative. In the
United States and Canada, you can also call 1-800-765-SMCS (765-7627) for
assistance during the hours of 8:00 am to 12:00 noon and 1:00 pm to 4:30 pm
(Central Time Zone), Monday through Friday.