MPR 6/3

MPR-6/3 Motor Protective Relay

new generation of microprocessor based relay designed to protect three phase induction motors. Featuring Directional Ground Fault and true RMS line currents are measured at a sampling rate of 0.5 mSec. The MPR-6 includes three temperature (RTD's or Thermistors) inputs, all combined to provide a comprehensive protection package.

The MPR-6/3 incorporates two main functions.

• Advanced, state of the art motor protection
• Supervision and communication.

Advantages at glance

• Directional Ground Fault
• Comprehensive package, 26 protective functions
• Ability to select each protective functions as Alarm, Trip, both or none.
• True RMS at a scan time of 0.5 mSec
• Full control and supervision through RS 485 with open Modbus protocol.
• Compact, simple to install and easy to operate.

Protection

• Too many starts
• Maximum start time
• Under current
• Load Increase
• Thermal level (Overload) - Two Levels
• Over-current Jam / Stall
• Over-current Short circuit
• Unbalanced current
• Ground fault current
• Over-temp. -RTD or PTC/NTC Thermistor
• External faults 1&2 - N.O / N.C contacts
• Current fluctuation (Broken Bar Detection)
• Analog Output

Configurable Operation

Any fault can be designated as an Alarm, Trip, both or none. Furthermore, two auxiliary relays can be specified to operate with any of the faults.

"Time To Trip" and "Time To Start"

When current exceeds the overload setting, a unique built-in algorithm calculates the time until the motor will be tripped (when thermal capacity is 100%), enabling the operator or host computer to take corrective action before tripping. After the MPR-6 has tripped the motor, it will calculate the time delay until the motor can be restarted, after cooling down.

Informative Data

An illuminated LCD provides clear status and statistical information.

Actual Data

• Phase currents
• Ground fault current
• Thermistor resistance
• Motor load in % of FLC
• Thermal capacity
• Time to trip
• Time to start
• Unbalanced current

Statistical Data

• Motor run time
• Total number of starts
• Total number of trips
• Last start time
• Last start peak current
• Last trip
• Last alarm
• Phase currents
• Phase currents

Communication

RS485 serial link with MODBUS RTU communication protocol, operating at baud rate of 1200 to 9600 bits/sec, enables monitoring of set points and actual parameters. Up to 32 MPR-6 relays can be connected to the host computer on the same twisted shielded pair.

Typical applications

• Small to medium size low and medium voltage motors.
• Motors in the Process Industry.
• Critical motors requiring special protection or supervision.