Electrical Technology 2020-8-11
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This post was last edited by sdscj0122 on 2020-8-11 08:21. It deals with multiple-choice questions related to the \"Power Safety Work Procedures\"; please indicate whether the answer is correct or incorrect. 3 points are awarded for correct answers, 2 points for incorrect ones, and 5 points for detailed responses. 126. It is prohibited to work on equipment whose power supply is disconnected only by a circuit breaker. ( ) Correct
Correct. Although high-voltage circuit breakers have strong breaking capacity, their opening stroke is very limited. The moving and stationary contacts of the circuit breaker are located inside the organic arc extinguishing chamber; whether it is in the off or on state can only be indicated by the opening/closing indicator, which is not easily visible from the outside. More importantly, the circuit breaker does not disconnect the power supply when it is in the off state; if there are problems with its control circuit or if there is cross-wiring, accidental contact, or improper operation, it will cause the operating mechanism of the circuit breaker to activate, resulting in the device being energized automatically. Furthermore, when the opening mechanism of the circuit breaker operates to open it, if its operating mechanism fails and the circuit breaker does not actually open, the position indicator may still be moved to the open position by that mechanism, resulting in an apparent open state of the circuit breaker and creating a false impression. Therefore, the Electrical Safety Work Procedures clearly state that it is prohibited to work on equipment whose power supply has been disconnected only by a circuit breaker. During maintenance outages, it is necessary to take the circuit breaker out of service and disconnect both the load-side isolator and the busbar-side isolator, thereby creating a clear and visible air insulation gap to meet the requirements for safe work
Correct. ? ?? ?Although high-voltage circuit breakers have a strong breaking capacity, their opening stroke is quite limited. The moving and stationary contacts of the circuit breaker are located inside the organic arc extinguishing chamber; whether it is in the off or on state can only be indicated by the opening/closing indicator, which is not easily visible from the outside. More importantly, the circuit breaker does not disconnect the power supply when it is in the off state; if there are problems with its control circuit or if there is cross-wiring, accidental contact, or improper operation, it will cause the operating mechanism of the circuit breaker to activate, resulting in the device being energized automatically. Furthermore, when the opening mechanism of the circuit breaker operates to open it, if its operating mechanism fails and the circuit breaker does not actually open, the position indicator may still be moved to the open position by that mechanism, resulting in an apparent open state of the circuit breaker and creating a false impression. ? ?? ?Therefore, the ‘Electrical Safety Work Procedures’ clearly state that it is prohibited to work on equipment whose power supply has been disconnected only using a circuit breaker. During maintenance outages, it is necessary to take the circuit breaker out of service and disconnect both the load-side isolator and the busbar-side isolator, thereby creating a clear and visible air insulation gap to meet the requirements for safe work
Correct. ? ?? ?Although high-voltage circuit breakers have a strong breaking capacity, their opening stroke is quite limited. The moving and stationary contacts of the circuit breaker are located inside the organic arc extinguishing chamber; whether it is in the off or on state can only be indicated by the opening/closing indicator, which is not easily visible from the outside. More importantly, the circuit breaker does not disconnect the power supply when it is in the off state; if there are problems with its control circuit or if there is cross-wiring, accidental contact, or improper operation, it will cause the operating mechanism of the circuit breaker to activate, resulting in the device being energized automatically. Furthermore, when the opening mechanism of the circuit breaker operates to open it, if its operating mechanism fails and the circuit breaker does not actually open, the position indicator may still be moved to the open position by that mechanism, resulting in an apparent open state of the circuit breaker and creating a false impression. ? ?? ?Therefore, the ‘Electrical Safety Work Procedures’ clearly state that it is prohibited to work on equipment whose power supply has been disconnected only using a circuit breaker. During maintenance outages, it is necessary to take the circuit breaker out of service and disconnect both the load-side isolator and the busbar-side isolator, thereby creating a clear and visible air insulation gap to meet the requirements for safe work
Correct. Working on equipment that is powered off only by a circuit breaker is prohibited; it is necessary to disconnect the isolating switch to ensure that there is at least one clear break point in all connections.