Naren - Motor Protection Relay Model - MPR

Model: APT17

This product is an Auto Start Unit with a motor protection system that safeguards the 3 Phase Motor against Overload, Dry Run, imbalance in currents and Single Phasing. This product has to be attached to the existing motor starter. It allows the motor load to pass through it. The current drawn in all the 3 lines are continuously monitored and displayed on the LCD. The low current and high current settings need to be adjusted by the user. The motor is turned OFF in case of over current, under current (dry run) and when any of the supply phases are absent thus protecting the motor from damages. The reason for the trip along with the tripping current is displayed on the LCD.
  • Auto Start Unit
  • Adjustable Power On Delay
  • Overload Protection
  • Adjustable maximum relay range
  • Dry Run (Under Current) Protection
  • Dry Run Restart Option
  • Single Phase Protection
  • Motor Cable Cut Protection
  • User Adjustable Overload and Dry Run Settings
  • 3 Phase Digital Ammeter
  • 3 Phase Digital Voltmeter
  • Error Display on LCD
  • Metal Body
  • Built in CTs
  • Connector type design
  • Motor ON Indication
  • Easy Setup and Installation
  • Rating: 1 to 30HP
Maximum Current Range:
  • Adjustable up to 99A
    Naren Motor Protection Relay can be connected in 2 configurations
  • Connect the incoming supply lines R,Y and B respectively
  • Connect C1 and C2 across (in parallel to) the Start/ON Push Button of the starter
  • Connect C3 and C4 in series with the holding contact of the Contactor
  • Pass all the 3 load wires through the holes provided
    The LCD powers up automatically when the supply is ON. The relay contacts C3 and C4 (normally open contacts) close when the load current is detected in all the 3 lines. C3 and C4 will remain closed till current in all the 3 lines is within the set limit. C3 and C4 open only during the faulty conditions or when the motor is switched off manually. The reason for the trip is displayed on the LCD. C1 and C2 (Normally open contacts) close for 5 seconds after the set power ON Delay if the Switch provided is in the ON position. The Auto Start functionality takes place during the arrival of the 3 Phase power supply.
Technical Specifications:
  • Normally open Dry Relay Contacts C1, C2 and C3, C4
  • Wire Size to be used for L1, L2 and C1, C2 is a minimum of 0.5 sq. mm
  • Relay Closing time when currents are detected : 1 second
Tripping time:
  • Overload - 12 seconds
  • Dry Run (Underload) - 8 seconds
  • Single Phasing - 2 Seconds
  • Unbalanced Current: 12 seconds
  • Minimum Holding Current: 1A
  • Turn the Overload [H( )] [green knob] to maximum (clockwise)
  • Turn the Dry Run [L( )] [Blue knob] to minimum (anticlockwise)
  • Turn ON the motor and observe the load current in the second line of the LCD
  • Set the Overload H( ) value to 2 points more than the load current by rotating and observing the change in H( ) value in the first line of the LCD.
  • Set the Dry Run L( ) value to 2 points less than the load current by rotating and observing the change in L( ) value in the first line of the LCD.
  • Note: Set the L( ) value to minimum if the Dry Run Protection is not required.
    Naren APT17 is used in all 3 Phase Submersible Starters as a protection mechanism to protect the motor against current and voltage irregularities. This device effectively switches OFF the motor in any irregularity and hence prevents burning of the motor windings. The reason for turning OFF is displayed on the LCD which makes the diagnosis easy. This device is rugged and is specifically designed for agricultural operations. The motor safeguarding devices like these are very critical which will save the users from the costs incurred due to motor failures.
    This product carries a warranty of 6 months from the date of purchase. Any issues within the warranty period will be attended to free of cost at our works in Bangalore. Post the warranty period, the product will be eligible for the paid service at our works. The invoice copy acts as a warranty card. The shipping of the product for repair will have to be done by the consumer.
    Product Helpline: +919972243774
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