Kalpana Enterprises

The multifunction numerical motor protection device provides complete protection of low voltage motors. The device has been developed keeping in view of varied customer needs and various applications of motors. Accordingly, the motor protection device incorporates the following:

• Precise estimate of the thermal image of motor for varying conditions of starting, running, overload, stopping, unbalance conditions. The negative sequence current calculations are taken into account for unbalance current conditions.
• Continuous monitoring of thermal capacity used and in case of power failure the last value of accumulated thermal capacity prior to power interruption is stored.
• Six thermal overload curves – 2.5C, 5C, 10C, 15C, 20C and 30C covering the complete range of motor applications.
• Motor start lockout feature inhibiting start of the motor, in case of non-availability of sufficient thermal reserve to complete the acceleration.
• In built Insulation resistance check function prior to start of motor to give a preliminary indication of the condition of insulation, so that the user can take appropriate action for low value of insulation resistance.
• Automatic setting of parameters function, which would set all the protection parameters only on entering the rated full load current as per the motor name plate details.
• Annunciation, in case, the motor fails to stop after the protection device issues trip command.

The salient features of device are:

• LED Seven Segment Display, brighter pixilation and longer life than LCD
• Continuous scanning and display 3 phase currents and thermal capacity used
• Annunciation for each type of fault
• Numerical Algorithm for fast, reliable operation
• Thermal Overload curves selectable as per requirement, Excellent accuracy and long-time stability of thermal curves due to complete software-based implementation
• Customized protection CT as per load requirement supplied with the relay
• Continuous self- supervision and fail-safe operation
• Man-Machine interface through keypad
• Upto five event trip records, FIFO based (with date and time stamping in model – HLEDx)
• Reset Inhibit function, Hour Counter, Online calibration, Password facility (on demand)
• Robust mechanical design and adequate IP 54 degree of protection by enclosure which is shock proof nonmetallic screw less unit

The device provides protection against the following:

• Overload
• Short Circuit
• Under Current
• Unbalanced current
• Locked Rotor
• Earth Fault
• Single Phasing (Phase Loss)

Following optional protections/ functions are available based on selected variant of MPD:

• Phase reversal
• Over Temperature (Thermistor Based)
• Over Voltage & Under Voltage
• Pre-Trip Alarm for thermal Overload or Definite time overcurrent
• PF, KW & KWH measurement
• Startup Counter with trip facility
• SSR Output for Short Circuit Protection
• Insulation Resistance check facility prior to start of motor
• Data communication over MODBUS RTU protocol between Motor Protection level and higher-level data acquisition for reporting, parameterization, fault annunciation, reset function and hour counter
• 4-20mA Analogue output
• Hour Counter
• Online Calibration
• Password Facility