Heating, Ventilation, and Air Conditioning (HVAC ) Electrical Practice Test

The capacitor start-capacitor run (CSCR) motor is known for providing what kind of torque?

1. Low starting torque

2. High starting and running torque

3. Consistent low torque

4. Instantaneous maximum torque

The correct answer is: High starting and running torque

The capacitor start-capacitor run (CSCR) motor is specifically designed to offer high starting and running torque, making it suitable for applications that require a strong initial push to overcome resistance when starting. The dual capacitor system utilized in CSCR motors enhances both the starting torque and the efficiency during running, allowing the motor to maintain high torque levels throughout its operational cycle. When the motor starts, the start capacitor provides a significant boost by creating a phase shift in the electrical current, which, in turn, improves the rotor's ability to generate torque right from the beginning. Once the motor reaches a certain speed, the start capacitor is switched out of the circuit, while the run capacitor continues to optimize the motor’s performance, ensuring it operates with a higher overall efficiency and maintains good torque at running speeds. This design feature distinguishes CSCR motors in applications like air conditioning compressors, where both high starting torque and consistent running performance are essential for adaptability to varying load conditions. Other options do not capture this balanced performance characteristic accurately, as they suggest either insufficient torque or a lack of efficiency during operation.