Motor Protection Relay
MPU 32 Series
- Protects through starting, running, and cooling cycles
- View measured values and event records, reset trips, and access setpoints remotely
- Ten year warranty
The Liitelfuse MPU-32 Motor Protection Unit provides current and temperature-based protection, metering, and data logging for three-phase low-voltage medium-horsepower induction motors.
This relay is ideal for retrofitting and upgrading obsolete or aging motor protection using existing CTs. See the PMA Family of Panel Mount Adapter Kits to replace common obsolete relays.
The Current Input Module (MPU-CIM) is the interface between the MPU-32 relay and the 5-A-secondary, 1-A-secondary, and sensitive current transformers. The MPU-CIM is ordered separately.
Overload - IEEE # 49, 51
Extends motor life and prevents insulation failures and fires.
Dynamic thermal model
Provides protection through starting, running, and cooling cycles.
Earth fault – IEEE # 50G/N, 51G/N
Prevents catastrophic failures and fires.
Current unbalance/Phase loss/Phase reverse – IEEE # 46
Prevents overheating due to unbalanced phases.
RTD temperature – IEEE # 38, 49
MPS-RTD module for high-ambient or loss-of-ventilation protection.
Phase loss/Phase reverse (current) – IEEE # 46
Detects unhealthy supply conditions.
Overcurrent – IEEE # 50, 51
Prevents catastrophic failures and fires; extends motor life.
Prevents motor damage by detecting mechanical jams or excessive loading.
Undercurrent – IEEE # 37
Detects low level or no-load conditions.
PTC overtemperature – IEEE # 49
Overtemperature (PTC) protection for high-ambient or loss-of-ventilation detection.
Starts per hour – IEEE # 66
Limits the motor starts per hour to prevent overheating.
Differential – IEEE # 87
Optional MPS-DIF module for sensitive winding-fault protection.
Reduced overcurrent mode
Minimises arc-flash hazards during maintenance.
View measured and calculated parameters with on-board display.
Separate current input module to reduce risk of open-CT hazard and for convenient installation.
Provides means for metering selectable parameters.
On-board 100-event recorder for data logging.
Internal circuits are conformally coated to protect against corrosion and moisture.
Data Sheets and Manuals
MPU-32 Data Sheet MPU-32 ManualMPU-CIM MechanicalMPU-CIM WiringMPU-32 Ethernet IP ManualMPU-32 and FPU-32 Modbus TCP ManualMPU-32 and FPU-32 TIA 485 ManualMPU-32 DeviceNet ManualTN MP18 Replacing MPU 16 with MPU-32
CAD Drawings and Models
MPU-32 CAD DrawingMPU-32 Wiring DiagramMPU-32 Wiring Diagram with EFCT
Software and Manuals
SE-Comm-RS v4,2 SoftwareMPU-32 FPU-32 Firmware Update Instructions
Protective Functions (IEEE Device Numbers)
Overload (49, 51), RTD temperature (38, 49), Phase reverse (current) (46), Overcurrent (50, 51), Jam, Earth fault (50G/N, 51G/N), PTC overtemperature (49), Unbalance (current) (46), Starts per hour (66), Differential (87), Phase loss (current) (46), Undercurrent (37)
65-265 Vac, 25 VA; 80-275 Vdc, 25 W
800 ms at 120 Vac
100 ms minimum
100 mA maximum
True RMS and DFT, Peak, 16 samples/cycle, and positive and negative sequence of fundamental
50, 60 Hz or ASD
Three Form C programmables
TIA-232 (standard); TIA-485, DeviceNet™, Ethernet (optional)
4-20 mA, programmable
Mounting (Control Unit)
Panel (standard), Surface (with MPU-32-SMK converter kit)
Mounting (Current Input Module)