BENSHAW RediStart MX2 SEP, Руководство пользователя

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7 - Theory of Operation
89
7 -
Theory of Operation
7.1 Control Modes of Synchronous Motor Operation
7.1.1 Brush Type (Field Control) Synchronous Motor Operation
The brush type (field control) synchronous motor will start as an induction motor. The field winding will
generate an AC voltage during
starting, and a resistor must be connected to the winding to control the voltage
levels generated. The size of the resistor is also partly responsible for the torque the motor generated during
starting. Once the motor has reached synchronizing speed, the field is applied and the motor synchronizes.
Figure 18: Brush Type Synchronous Motor Operation Curve
Synchronizing Conditions :
The following conditions must be true before the controller will apply the DC field to a brush type motor:
• A start command must be given.
• Motor slip must be less than the slip percentage (CFN 01 / P2) or the motor speed must be greater than
100% - slip parameter (CFN 01 / P2).
• The Field Application delay Timer (QST 02 / P3) must expire.
• The digital input(s) (I/O 01–03 / P40–42) programmed as “Field Apply”.
See Also • Slip Percentage (CFN 01 / P2) on Page 63.
• Field Application Delay Timer (QST 02 / P3) on Page 60.
•
Digital Inputs (I/O 01–03 / P40–42) on Page 75.
Stator Protection must be set up for:
• Lagging Power Factor to trip, in the case of loss of synchronization.
• Stator IOC (Over Current) must be set for a level approximately 1.5 to 3 times the motor stator FLA that
will indicate if the rotor has pulled out, and is slipping poles. Contact the motor manufacturer or
Benshaw for more information.