Anonymous asked in Science & MathematicsEngineering · 1 month ago

Hi I need help with this other 4 questions about of motors ?

5º what are the types of solid state motor starters and how their starting control operates.?

6º.- Explain what is protection against phase failure, protection against phase reversal, protection against incomplete sequence and protection against stop in a motor

7º Describe the design criteria for relay protection

8º Explain and describe how the selection of protections against overcurrent due to short circuit and earth faults is made. What are the devices that are used?

1 Answer

  • 1 month ago
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    5. The solid-state motor starter uses triacs and transistors for power control in AC motor starters, and SCRs and transistors for DC motor starters. These controls have provided the function of a traditional motor starter, yet provide additional protection for the motor.

    6.Motor overcurrent differential protection measures the current flow into a load and compares it to the current measured on the neutral side of the motor. A current difference is detected as a fault. ... By detecting faults at a low level, damage may be confined to windings solely.

    7. Setting of the motor protection relay is based on the motor datasheets information and system configuration.

    8. Branch-Circuit Short-Circuit and Ground-Fault Overcurrent Protection is the final article of a four part series. The series is titled “Motor Calculations” and covers the Code and calculations for single general motor applications. In parts I – III we discussed calculating the motor load, the ampacity of the motor branch-circuit conductors, and how to properly size motor overloads. The branch-circuit short-circuit and ground-fault protection devices do not prevent short-circuits or ground-faults. They protect the motor branch-circuit, the wires between the last over-current protection device (OCPD) and the motor, in the event of a short-circuit or ground-fault.

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