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Machine Watch

The machine watch will control the start and stop operation of a motor while monitoring various vital conditions. The following inputs and outputs are available:

  • 12 definable 4-20mA inputs

  • 2 RTD PT100 temperature inputs

  • 1000V, 3-phase sense inputs

  • 1 Thermistor input

  • 2 Current Transformer (5A) inputs

  • 3 Contactor outputs

  • 2 Relay outputs

  • 1 external trip input source

  • MC auxiliary input

  • SC auxiliary input

  • Overload or Under current conditions

  • Under voltage conditions

  • Incorrect Phase rotation

  • Anti-windmill function


The start and stop sequence operation can control a shorting contactor (anti-windmill). Before starting the motor, machine watch will open the shorting contactor, confirm the open condition by an auxiliary input and then energize the motor contactor to start the motor.


If an auxiliary contact is in an incorrect state machine watch will stop the motor and indicate either an SC or MC fault.


If any of the trip sources are in error machine watch will either stop the motor if it is running, or not allow the motor to be started. The reason for failure will be indicated on the display. The fault must be cleared and Machine watch reset before being able to start the motor. All monitored inputs may be disabled if not desired, (excluding MC and SC auxiliary contact inputs).


Machine watch also contains an hour run meter and service interval timer.


All setup information and hours of operation are stored in the personality key which plugs into the back of the machine watch. The personality key contains all information specific to each motor, such as settings, and hours of operation. NEPEAN Power Electronics is also able to provide a pre-programmed personality key.

Main Functions
  • Minimum (Low) and Maximum (Over) level set points, are offered on sensors
    Inputs may be checked for correct operation by monitoring for operation within normal operating parameters, or for an expected change when running. This is most applicable where an increase in vibration is expected upon the fan being started. This may also apply to pressure, airflow or even temperature. If the minimum set point is not achieved when expected, an appropriate action may be taken by Machine watch. This will give the user confidence in knowing that the sensor is changing as expected and is functional.

  • Overload
    With two CT inputs Machine watch can be set to perform overload function that has traditionally been done by an external protection module. Four protection curves are offered: STD Inverse, Very Inverse, Extreme Inverse, and long time.


  • Gas Monitor Action
    The 4-20mA inputs can be used to connect any type of sensor including gas, airflow etc. There is also specific CH4 (methane) gas trip mode.


  • Data Logging
    An extensive log is included in Machine watch to determine a history of operation and what events are causing the motor to stop. The log will include the start time, number of run hours, trip readings of sensors and reason for stop.

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