NAREN MOTOR PROTECTION UNIT
Model: MPU-25 (with clamp for DOL Starter)
Tagline
“MPU-25: The Smarter Way to Shield Your 3-Phase Motors.”
Engineered for MK type DOL 3-phase motor starters
Power Rating: 1HP to 7.5HP
FEATURES
clamps with mounts for DOL starter fittings
wires provided for easy connections
Digital Overload Relay — Prevents motor damage from drawing excess current loads
Digital Dry Run Relay — Protects against dry-run conditions when water levels are low
Auto Start Unit — Automatically resumes operation after power restoration
Single Phase Preventor — Blocks motor operation in case of phase failure
Auto Current Adjustment — Sets optimal current thresholds automatically
3 Phase Voltmeter — Displays real-time voltage across all phases
3 Phase Ammeter — Monitors real time current for diagnostics and control
Phase Reversal Tripping — Ensures safe motor direction control
Adjustable Power-On Delay — Customizable startup delay for added safety
Fault Indication with Fault Current Display — Immediate issue detection, minimal downtime
Connections:
Naren MPU25 can be connected in 2 configurations
1) Connecting MPU at the load end
Connect the output of the Starter to L1, L2 and L3 respectively (all 3 load wires)
Connect the motor cables to M1, M2 and M3
Connect C1 and C2 across start push button
Connect C3 and C4 in series with the No- Volt coil of the Contactor
2) Connecting MPR at the Supply end
Connect the incoming supply lines (load wires) to L1, L2 and L3 respectively
Connect M1, M2 and M3 (same load wire sizes) to the incoming of your motor starter
Connect C1 and C2 across start push button
Connect C3 and C4 in series with the No- Volt coil of the Contactor
Operation:
The LCD powers up automatically when the Supply is detected in all the 3 lines. On sensing the current in all the 3 Phases, C3 and C4(Normally open contact) close. 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 along with the trip current is displayed on the LCD.
Technical Specifications:
Normally open Dry Relay Contacts
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
Dry Run (Underload) - 8 seconfds
C1 and C2 closing time once the current is detected: About 2 Seconds
Application:
Naren Motor Protection Unit 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.
WARRANTY:
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.
