Red Seal Industrial Mechanic (Millwright) Practice Exam

What is the first step in troubleshooting an electrical motor that won’t start?

1. Check for overload mechanisms

2. Inspect for mechanical obstructions

3. Check for power supply issues

4. Test the motor's insulation resistance

The correct answer is: Check for power supply issues

The first step in troubleshooting an electrical motor that won’t start is to check for power supply issues. This step is critical because the motor requires a proper electrical supply to function. Without voltage or with inadequate voltage, the motor will not start, regardless of its internal condition or any connected mechanical systems. Establishing the presence of power ensures that any further diagnostics are meaningful. If there is no electrical supply, investigating mechanical obstructions or checking overloads would be unnecessary, as the root cause of the problem—lack of power—would remain unaddressed. Once power issues are confirmed to be satisfactory, further investigation can proceed with checking overload mechanisms, mechanical obstructions, or testing insulation resistance, depending on the symptoms exhibited by the motor. Therefore, prioritizing the power supply makes logical sense in the troubleshooting process.