HOLT Electricians Practice Exam

For motors that include integral thermal protection, what must the overload protection correspond with?

1. Motor temperature rating

2. Service factor and current load

3. Motor nameplate current and voltage

4. Manufacturers testing conditions

The correct answer is: Service factor and current load

The correct choice emphasizes that overload protection must correspond with the service factor and current load of the motor. This is critical because the service factor indicates how much overload a motor can handle safely without overheating. It provides a buffer above the motor's rated load, essentially allowing for variations in operating conditions that could lead to increased current draw. By matching the overload protection with both the service factor and the current load, it ensures that the motor's thermal protection is effective in preventing damage from excessive currents during operation. Moreover, understanding the relationship between the service factor and the current load is essential for maintaining the motor's efficiency and longevity. Having overload protection that is appropriately calibrated to these parameters helps to prevent costly downtime and repairs, ensuring that the motor operates within its safe thermal and electrical limits. This puts emphasis on the importance of considering both the motor's design specifications and its operational context when establishing overload protection.