The Digital 610 Motor Protector is a micro controller based motor and compressor protector that provides over-current and temperature protection for across-the-line or part winding motors and their A/C compressors. The control has a current sensing circuit module that derives information from up to three C.T.s (current transformers). When a current in any phase exceeds the pre-determined adjustable “trip level”, the control de-energizes the across-the-line motor starter, contactor or control circuit. When currents exceed the trip point, the control calculates the energy dissipated in the motor due to the over current and trips before damage can occur. The greater the current above “trip level”, the shorter the time to trip. The lesser the current above “trip level”, the longer the time to trip. The time to trip is two seconds for locked rotor and can be over 20 minutes for marginal overloads.

The Digital 610 also verifies correct motor phase rotation upon power up. If the rotation is out of sequence, the controller will shut the motor off within 2 seconds after power up. The controller can also be set to trip on an adjustable phase imbalance.

The Digital 610 has a temperature sensing circuit that uses up to two temperature sensors that are typically attached to an A/C compressor's exhaust (discharge) line and and/or oil crankcase. The controller will trip the compressor's motor off when the exhaust temperature exceeds an adjustable trip point or when the crankcase oil temperature is too low or high.

Input power is provided by 24 VAC. Two sets of isolated Form C relay contacts are provided. The TRIP relay is normally closed and will open during a trip condition. The ALARM relay can be programmed to close on particular conditions and is used for alerting at a remote site.

A optional Modbus RTU interface is available in the controller which allows all parameters to be set over Modbus and all present settings and current input and output values to be read over Modbus.