Total capacitance for a CSR motor with a 10 microfarad run capacitor and a 110 microfarad start capacitor is:

Total capacitance for a CSR motor with a 10 microfarad run capacitor and a 110 microfarad start capacitor is:

• A. 100 microfarads
• B. 110 microfarads
• C. 120 microfarads
• D. 130 microfarads

Answer: (C)

In a capacitor start–run motor, the run capacitor stays in the circuit, and the start capacitor is connected only during startup. When the motor is starting, both capacitors are effectively in the circuit at the same time, so they act like capacitors in parallel and their values add. That gives a total starting capacitance of 10 μF + 110 μF = 120 μF. After the motor reaches speed, the centrifugal switch disconnects the start capacitor, leaving only the run capacitor in the circuit (10 μF).

In a capacitor start–run motor, the run capacitor stays in the circuit, and the start capacitor is connected only during startup. When the motor is starting, both capacitors are effectively in the circuit at the same time, so they act like capacitors in parallel and their values add. That gives a total starting capacitance of 10 μF + 110 μF = 120 μF. After the motor reaches speed, the centrifugal switch disconnects the start capacitor, leaving only the run capacitor in the circuit (10 μF).