The intelligent load feeder (ILF) is a complete, digital load feeder consisting of the ILM (intelligent link module 3RC7) and the matching contactor and motor protection/circuit breaker.
Simply digital. Intelligent on many levels.
Preassembled
SIRIUS 3RA24 contactor assemblies for star-delta (wye-delta) starting, up to 90 kW
The 3RA24 contactor assemblies for star-delta (wye-delta) starting in sizes S00 to S3 can be ordered as follows:
- Fully wired and tested, with electrical and mechanical interlock
Benefits of preassembled star-delta combinations
- Space-saving
- Different connection technologies: screw terminals, spring-type terminals
- Only one order number
Customer assembly
Star-delta combinations for customer assembly
Naturally, we also offer you the option of ordering and assembling individual contactors in different performance classes from 5.5 kW to an output of 500 kW for star-delta combinations. As of a desired output of over 90 kW, the combinations of individual products must be assembled by the customer.
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.
