Journeyman Electrician Practice Exam

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Prepare for the Journeyman Electrician Exam. Test your skills with multiple-choice questions designed to help you succeed. Each question comes with hints and detailed explanations to assist in your study process.

Practice this question and more.

What characteristic is needed in a short-circuit protective device for an air-conditioner motor-compressor?

High voltage tolerance
Time delay
Immediate response
Low current threshold

The correct answer is: Time delay

The characteristic needed in a short-circuit protective device for an air-conditioner motor-compressor is a time delay. This is crucial because the motor-compressor may experience inrush currents when it starts up, which are significantly higher than its normal operating current. If the protective device were to react immediately to these transient inrush currents, it could disrupt the operation by unnecessarily tripping and shutting down the air conditioning system. The time delay allows the device to distinguish between normal start-up conditions and actual short circuits or overload conditions. Once the motor has stabilized and if there is an ongoing fault, the protection device can then trip to prevent damage to the compressor or the circuit. This balance is essential in maintaining the functionality and longevity of the air-conditioning system while ensuring safety against real faults.