1、 How to connect the starting capacitor and running capacitor to the AC motor?
A single-phase AC motor itself does not have starting torque and must rely on capacitor phase-shifting to generate a rotating magnetic field in order to start.
The common connection method is: main winding+secondary winding+capacitor.
1. Basic wiring structure
There are generally three sets of lead wires inside the motor:
Main winding (running winding): low resistance, thick wire
Secondary winding (starting winding): high resistance, thin wire
Common end
2. Only starting capacitors (small power motors, fans, etc.)
Fire Line L → Common Terminal C
Neutral wire N → Main winding M
Secondary winding S → one end of the starting capacitor
Start the other end of the capacitor → neutral wire N (or live wire L, depending on the direction of rotation)
After starting, the centrifugal switch will automatically disconnect the starting capacitor.
3. Start capacitor+running capacitor (dual value capacitor motor, commonly used in air compressors and water pumps)
Structure:
The running capacitor is always connected in series with the secondary winding
Start the capacitor in parallel with the running capacitor and connect it in series with a centrifugal switch
Wiring steps:
Fire Line L → Common Terminal C
Neutral wire N → Main winding M
Secondary winding S → one end of the operating capacitor
Run the other end of the capacitor → neutral line N
Start one end of the capacitor → secondary winding S
Start the other end of the capacitor → centrifugal switch → neutral wire N
At startup: Two capacitors work together with high torque
After the speed increases, the centrifugal switch is disconnected, leaving only the running capacitor to work