Contractors or Relays Burn Out

Have you checked the line voltage?Low line voltage.Increase voltage to no less than 10% under compressor motor rating.
 Excessive line voltage.Reduce voltage to maximum of 10% over motor rating.
Have you checked the wiring?Improperly wired.Check wiring against diagram and correct as necessary.
Do you have correct contactor or Relay?Incorrect contactor or Relay.Replace contactor or Relay with model that has properly selected characteristics.
How is the contactor or relay mounted?Incorrect mounting.Mount in correct position.
Is the contactor or relay vibrating?Contactor or relay vibrating.Tighten mounting screws, mount contactor or relay in Rigid location.
Is the compressor short cycling?Short cycling.Reduce number of starts per hour.