ELECTRIC MOTOR APPLICATIONS
Variable frequency drive (VFD) operated motors
It is estimated that between 15% and 20% of motors are powered by variable frequency drives, and this number is on the rise.
It is estimated that between 15% and 20% of motors are powered by variable frequency drives, and this number is on the rise.
The variable frequency drive increases the residual currents generated in the rotor due to the magnetic field. While this has negligible effects on small motors, in larger motors, the intensity of the current passing between the balls and the bearing race can accelerate wear and corrosion. Therefore, these currents must be cut off.
An insulated protection system is recommended to prevent currents from affecting the motor, by means of an insulated shaft, insulated bearing housing, or insulated bearings.
CEMER motors are equipped as standard with insulated bearings or bearing housings starting from frame size 280 and above. For other brands, please consult us.
The motor’s power should always be oversized by at least 10% to compensate for performance losses caused by the variable frequency drive.
It is recommended that the motor be equipped with PTC temperature sensors in the winding.
The forced ventilation unit is used to keep the variable frequency drive operated motor cool when it rotates at low speeds. It keeps the motor cool with an airflow equivalent to when the motor is rotating at nominal speed.
Forced ventilation should always be installed on constant torque machines for speeds below 35 Hz. On quadratic torque machines (pumps, fans, agitators…), the installation of a forced ventilation unit is not necessary. Please consult CEMER.
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Forced ventilation units must always be connected to a power supply that is independent of the motor and not routed through the variable frequency drive.
CEMER FORCED VENTILATION UNIT
- Options: Three-phase 230/400 V or single-phase 230 V.
- Structure: Sheet steel with primer paint.
- Motor: Compact aluminium installed inside the unit.
- Design: Modular, adaptable to our CEMER motors ranging from frame sizes 63 to 355, and easy to assemble (for other brands, please consult us).
CEMER: We offer a kit that attaches to the motor. The unit can be sold separately or assembled on the motor.
COSGRA: Any motor can be equipped with a forced ventilation unit.
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We specialize in problem-solving.
*All fields are required.