Variable speed drive of centrifuge leads to higher profits at chemical plant
A chemical plant used a two-speed motor in the centrifugal drive of a dye production process. The stepwise speed control of the motor presented difficulties in finding the exact centrifuge speed for various dye products. This resulted in poor productivity and product quality. The system also had high service costs and expensive downtime caused by heavy stress on the belt and bearings of both the motor and the centrifuge.
The problems were solved by installing an ABB's frequency converter with standard squirrel cage motors instead of the two-speed motors. The frequency converter's stepless speed control allows optimum speed setting for different products. The product quality and the productivity are improved as several different products can be produced in one centrifuge thanks to the linear speed control of the ABB's frequency converter.
System diagram with the centrifuge, motor and drive
Solved Problem
- Speed was not matched to different dye processes
- Abrupt speed changes caused mechanical stress and breakdowns
Solution
- Frequency converter: 133 kVA
- Motor: 90 kW, 800 rpm
- Voltage: 660 V
Benefits
- Improved product quality due to precise speed control
- Reduced maintenance costs because of soft starting
- Higher productivity resulting from greater reliability