Motor Capacitors

Start and Run Capacitors

A start capacitor provides additional starting torque for a short period while the motor accelerates.

A run capacitor remains connected while the motor operates and helps it run efficiently with the correct torque.

Start and run capacitors are not interchangeable. Always replace the capacitor with the correct type for the motor and electrical circuit.

Choosing the Correct Replacement Capacitor

Check the information printed on the original capacitor before ordering. Important specifications include:

• Capacitor type: start or run
• Capacitance rating in microfarads
• Voltage rating
• Capacitance tolerance
• Spade terminals or flying leads
• Number and arrangement of terminals
• Capacitor diameter and length
• Mounting arrangement

Motor capacitors are normally marked in microfarads, shown as µF, uF or sometimes MFD.

The replacement should have the same capacitance rating as the original component. Its AC voltage rating must meet or exceed the rating specified by the motor or original capacitor. The capacitor type, terminals and physical dimensions must also be suitable for the installation.

Check the Motor and Pump

A motor that buzzes or fails to start does not necessarily have a faulty capacitor. Before fitting a replacement, check that the pressure-washer pump and motor shaft can turn correctly and are not seized.

Repeated capacitor failure may indicate another problem, including excessive motor load, incorrect supply voltage, damaged windings, a faulty centrifugal switch or an unsuitable capacitor.

Electrical Safety

Motor capacitors can retain a potentially dangerous electrical charge after the pressure washer has been disconnected from the power supply. Testing, discharging and replacing a capacitor should only be undertaken by a suitably competent person.

Always isolate the machine from the electrical supply and confirm that the circuit is safe before carrying out any work.

For help checking capacitor compatibility, contact Flowjet Cleaning Equipment on 015395 66193 or sales@flowjet.co.uk.