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CASCADE DRIVES
A cascade drive can be used advantageously for
the control of the revolution per minute of asynchronous motors with collector
rings. During the change of the revolution per minute the so-called slip
power generated in the rotor of the motor will be recuperated into the
mains by a thyristor equipment. If the need for changing the revolution
per minute does not extend to the full range then the price of the equipment
can be substantially lower, than in the case of inverter applications.
E.g. if the required changing range of revolution per minute is within
70...98% then the type power of the drive will be only 30% of the motor
power.
Due to the above, the cascade drive can be used
favorably for the change of the revolution per minute of pumps and fans.
In the case of supplying the motors of a pump system, a single current
rectifier is able to supply even 4 motors.
The VHJ Ltd. supplies cascade drives in the power
range 20kW...2MW.
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