Rockwell-automation SA500 Drive Configuration and Programming Manual de usuario descargar pdf (Pagina 115)

Constant Power Calibration

E-1

PPENDIX

Constant Power Calibration

Typically, an induction motor operating at or less than its rated speed will be capable of

generating its rated torque output. When a motor is operating at more than its rated

speed, its ability to generate torque decreases as the speed increases. To

compensate for this reduction of torque-producing capability, the magnetizing current

can be reduced as a function of motor speed or an external RPM signal. Reducing the

magnetizing current (Iz) enables the motor’s voltage to remain constant at speeds up

to four times base speed. This allows operation in the motor’s constant power region.

See figure E.1. The maximum speed attainable is dependent upon the motor and the

application. Motors typically can only be operated in the 1.5:1 to 2:1 speed ranges.

Constant power capability is only available for applications using induction motors with

Vector - Speed Loop Enhanced regulators. You need to select Constant Power on the

Motor Data parameter entry screen to enable constant power operation.

Figure E.1 – Typical Motor Operation in the Constant Torque and Constant Power Regions

Pt. 1

Pt. 2

Pt. 3

Pt. 4

Pt. 5

Pt. 6

Pt. 7

Pt. 8

Pt. 9

Pt. 10

Constant Torque

Operating Range

Constant Power

Operating Range

Rated Motor

Voltage

Rated Motor

Torq ue

Motor Speed

1 2 ... 110 111 112 113 114 115 116 117 118 119 120 ... 125 126

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Rockwell-automation SA500 Drive Configuration and Programming Manual de usuario Pagina 115