Connectors & Cables

Capacitors in a servo drive

Point at a number or a part of the drawing.

1. 1Mains input terminals

   Where the three-phase supply enters the drive.

2. 2Film capacitors

   Filter capacitors across the incoming lines. They suppress electrical noise (EMI) that the drive would otherwise send into the supply.

   Film Capacitor / Filter Capacitor

3. 3Rectifier

   Turns the incoming AC into DC for the DC bus.

4. 4DC bus capacitors

   Electrolytic capacitors that store energy on the DC bus and smooth its voltage. They wear out with heat and age, so they are replaced in drive repairs.

   Electrolytic Capacitor

5. 5Power module

   Switches the DC bus voltage into the variable AC that drives the servo motor.

6. 6Can and sleeve

   The aluminium can holds the wound foil. The plastic sleeve insulates it and carries the rating and the polarity stripe.

   Electrolytic Capacitor

7. 7Safety vent

   Opens under internal pressure when the capacitor fails, instead of letting it burst. A bulging vent means the capacitor needs replacing.

   Electrolytic Capacitor

8. 8Screw terminals

   Bolt the capacitor to the DC bus bars.

   Electrolytic Capacitor