Motor circuit breaker - connections

Thread starter Ivan001
Start date Feb 10, 2020
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Circuit Circuit breaker Motor

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SUMMARY

The discussion centers on the wiring connections of motor circuit breakers, specifically addressing the use of terminals 4 and 5 for optimal functionality. It highlights that connecting a transformer via terminals 2 and 4 is not advisable, as it does not ensure proper phase voltage management. The conversation emphasizes that terminals 5 and 6 remain unused in this configuration, which is not optimal for 3-phase overload relays that require current on all three legs. This wiring method ensures that all phases are adequately monitored and protected.

PREREQUISITES

Understanding of 3-phase electrical systems
Knowledge of motor circuit breakers and their terminal functions
Familiarity with overload relay requirements
Basic principles of transformer connections

NEXT STEPS

Research the wiring configurations of motor circuit breakers
Learn about the specifications and requirements of 3-phase overload relays
Study transformer connection methods in 3-phase systems
Explore the implications of unused terminals in circuit breaker configurations

USEFUL FOR

Electrical engineers, technicians working with motor control systems, and anyone involved in the design or maintenance of 3-phase electrical installations.

Feb 10, 2020

Ivan001

Why we use such connection between 4 and 5 terminals? Why the transformer isn't connected via 2 and 4 terminals from CB, the voltage will still be 380V because it's between two phases? In such situation the terminals 5 and 6 will stay unused, why not on this way?