Star-delta contactor assemblies
With a star-delta combination that is already assembled in the performance range from 5.5 kW to 90 kW or as individual parts for customer assembly up to a performance class of 500 kW, we offer an affordable, space-saving, and highly available option for reliably starting asynchronous motors.
Star-delta contactor assemblies portfolio
Highlights at a glance
Preferred circuitry
A star-delta (wye-delta) circuit reduces the starting current to 1/3 of the current compared to the current values for direct-on-line starting. However, when switching over from the star connection to the delta connection, the motor may be subjected to compensation processes, reinforced by an unfavorable constellation of line frequency and rotor field, which could result in higher current peaks than would be the case if the stationary motor were connected directly in the delta circuit.
An unfavorable scenario could lead to the following problems:
• Tripping of short-circuit protection devices,
• Welding or substantial contact erosion of the delta contactor,
• High dynamic load on the motor.
When connecting the motor using the preferred circuitry, the switchover currents from the star to the delta connection can be reduced.
This can avoid the problems mentioned above.
