Synchronous motors in CFC control mode

The permanent magnets increase the voltage induced in the winding of the motor as the speed increases. This limits the amount of the current that can be injected, as only the difference between the voltage in the DC link of the inverter and the induced voltage is available as the voltage. When the voltage limit is reached, the torque drops at higher speeds. To enable operation to the right of the voltage limit characteristic curve, a field-weakening current must be injected. The field weakening function (in preparation) is active by default. Note that the required current for the same torque is significantly higher in field weakening.

SEW-EURODRIVE recommends a PWM frequency of 8 kHz or 16 kHz for the following motors:

• CMP40/..50/..63 for speeds above 4500 min^-1
• CMP71/..80/..100 for speeds above 3000 min^-1
• CM3C63/..71/..80/..100 for speeds above 3000 min^-1
• CM3P71/..80/..100 for speeds above 2000 min^-1

SEW‑EURODRIVE recommends using the following temperature sensors:

• KTY84-130 (SEW-EURODRIVEdesignation: KY)
• Pt1000 (SEW-EURODRIVE designation: PK)