Elevator Mechanic Practice Exam

What is the proper way to test incoming voltage?

1. Using a single-phase AC meter

2. Using a ground fault circuit interrupter

3. 3 phase AC using digital meter: L1-L2 L1-L3 L2-L3

4. Using a 12V car battery

The correct answer is: Using a single-phase AC meter

To test incoming voltage accurately, the best approach involves using a three-phase AC digital meter, which measures the voltage between different phases. This method allows for a thorough assessment of all three phases of the electrical supply, ensuring you can check how the system is functioning under operational conditions. When using a three-phase AC digital meter, measuring the voltage between combinations of the phases (like L1-L2, L1-L3, and L2-L3) provides crucial information about the balance of the electrical supply, which is vital for the safe and efficient operation of elevator systems. It helps identify any issues with voltage discrepancies that could affect performance or lead to equipment failure. The single-phase AC meter, while useful for specific applications, does not provide the full scope needed to assess a three-phase system. Ground fault circuit interrupters are safety devices and are not designed for measuring voltage; their primary function is to protect against electrical shocks. A 12V car battery is not relevant for testing incoming voltage at higher voltages typically found in elevator systems, as it operates at a completely different voltage level from what would be tested in those environments.