Terasaki MPR-6-DGF Motor Protection Relay – Part No. 833831

Product Information

Manufacturer / Brand	Terasaki
Model (front panel)	Motor Protection Relay MPR-6-DGF
Ordering code (box label)	MPR6-DGF 1-2-3T-M-M-TE
Part number (box label)	833831
Other code on label	WC1916B-122-07
Related ordering code	MPR6-DGF1-110DC-3R-M-TE / 833821 (Not verified – not shown on the photographed label)
Product Type	Digital motor protection relay, panel (door) mounting
Front panel	LCD display, LEDs On / Start / Run / Alarm / Fault, keys Page, Select, Up, Down, Select 1 / Reset, Store
Accessories in photo	Plug-in green terminal connectors, original carton
Supply voltage / CT rating	Not clearly visible in the supplied photograph
Marking	CE
Condition	Refurbished
Supplier	SM MARINE SERVICE™, Chattogram, Bangladesh

Product Introduction

The Terasaki MPR-6-DGF is a digital motor protection relay used in marine switchboards and motor control centres to protect low-voltage motors such as pumps, fans and compressors. It monitors the three motor phase currents, earth fault current and motor temperature and trips the starter when a dangerous condition is detected. SM MARINE SERVICE™ supplies Terasaki switchboard components and motor protection relays worldwide. Visit https://www.smmarineservice.com/ for more marine automation and electrical spare parts.

What Is This Equipment?

The MPR-6 platform is a microprocessor-based motor protection relay that builds a thermal model of the motor from true-RMS current measurement. It protects against supply abnormalities, motor and cable faults and operator errors, shows motor data on its LCD, and gives alarm and trip outputs to the starter and alarm system. The same MPR-6 relay family is also sold under other brands, for example Solcon and Toshiba; the unit shown carries Terasaki branding.

Main Features

• Thermal capacity (overload) protection based on a motor thermal model
• Maximum start time (stall) and too-many-starts protection
• Over-current jam and short-circuit protection
• Under-current and load increase detection
• Current unbalance and ground (earth) fault protection
• Over-temperature via RTD or PTC/NTC thermistor, with sensor disconnection alarm
• Two external fault inputs
• Separate alarm and trip levels with adjustable delays for main functions
• Programmable inputs, outputs and analogue output
• RS-485 Modbus communication for remote monitoring and programming

Terasaki MPR-6-DGF motor protection relay with original box (part no. 833831) and plug-in terminals – SM MARINE SERVICE™

Main Technical Specifications

Data for the MPR-6 relay family from manufacturer literature. The exact supply voltage and ratings of this unit depend on the ordering code and must be confirmed.

Measurement	True RMS, 0.5 ms sampling
Current inputs	3-phase currents + ground current
Temperature inputs	RTD or PTC/NTC thermistor
Supply voltage (family)	230 VAC (175–250 V) or 115 VAC (88–125 V), 45–65 Hz; DC versions according to ordering code (Not verified)
Communication	RS-485, Modbus protocol
Display	LCD: phase currents, % FLC, ground current, unbalance, temperature, thermal capacity, time to trip / start, run time, start and trip counters, last trip data
Indicators	On, Start, Run, Alarm, Fault LEDs
Keys	Page, Select, Up, Down, Select 1/Reset, Store
Ordering code of this unit	MPR6-DGF 1-2-3T-M-M-TE

Inside the Unit: PCBs, Modules & Part Numbers

No separate PCB part numbers are published for the MPR-6. The numbers below are taken from the box label or supplier listings.

MPR-6-DGF Relay – 833831

Complete relay, ordering code MPR6-DGF 1-2-3T-M-M-TE, label code WC1916B-122-07.

MPR-6-DGF Relay – 833821 (related)

Ordering code MPR6-DGF1-110DC-3R-M-TE (110 VDC version according to the code – Not verified).

MPR-6-DGF Relay – MPR6-DGF 1-2-3R-M-TE (related)

Ordering code seen on supplier listings (Not verified).

Main Processor & Display Board

Microprocessor, LCD and keypad board behind the front panel. Part number: Not verified.

Input / Output & Power Supply Board

CT inputs, temperature inputs, relay outputs, RS-485 and power supply. Part number: Not verified.

Plug-in Terminal Connectors

Green removable terminal blocks supplied with the relay (shown in the photo).

Main Components & Related Units

• MPR-6-DGF relay with plug-in terminals
• External current transformers (3-phase) and core-balance CT for earth fault
• RTD / thermistor sensors in the motor
• Motor starter contactor and Terasaki switchboard / MCC
• Same family: Solcon MPR-6, Toshiba MPR-6

Marine & Industrial Applications

• Motor starters in ship main and emergency switchboards
• Cargo, ballast, fire, cooling water and fuel pumps
• Compressors, fans and thrusters (LV motors)
• Process industry and critical motors on shore

Front panel of the Terasaki MPR-6-DGF with LCD, LEDs and keypad

Common Problems & Troubleshooting

• Nuisance overload trip: check FLC setting, CT ratio and motor load.
• Earth fault trip: measure motor and cable insulation; check core-balance CT wiring.
• Unbalance trip: check supply phases, contactor contacts and cable terminations.
• Temperature sensor alarm: check RTD/thermistor wiring for open circuit.
• Too many starts: wait for the start inhibit time to expire before restarting.
• No display: check auxiliary supply voltage against the ordering code.

Safety note: The relay is connected to CT circuits and motor starters. Never open a CT secondary circuit while the motor runs. Isolate the starter and follow permit-to-work procedures before replacing the relay.

Common Alarms

Documented protection functions with alarm and/or trip indication include: thermal capacity, current unbalance, ground fault, under current, short circuit, over-temperature, disconnected temperature sensor, maximum start time, too many starts and external faults. Exact display texts depend on the software version.

Maintenance Tips

• Record all settings before replacing a relay and store them in the new unit.
• Check trip and alarm counters and last trip data regularly.
• Test the trip circuit during planned maintenance.
• Keep the front panel and terminals clean and tight.

Spare Parts & Replacement Availability

For a quotation, please send the label photo with the full ordering code (e.g. MPR6-DGF 1-2-3T-M-M-TE) and part number (833831 / 833821), required quantity and vessel name. SM MARINE SERVICE™ ships worldwide from Bangladesh and China. Specific condition and availability are subject to confirmation.

Why This Equipment Is Still Used

The MPR-6 offers complete motor protection in one compact unit and is installed in many marine switchboards. An identical replacement with the same ordering code fits the existing cut-out and wiring without modification.

FAQ

What is the Terasaki MPR-6-DGF?
A digital motor protection relay for low-voltage motors.

What is the part number of this unit?
833831, ordering code MPR6-DGF 1-2-3T-M-M-TE (box label).

What is part number 833821?
A related MPR6-DGF version, MPR6-DGF1-110DC-3R-M-TE (Not verified).

Does the ordering code matter?
Yes, it defines options such as supply voltage; always order the same code.

Which protections are included?
Overload, stall, too many starts, jam, short circuit, under current, unbalance, earth fault and temperature.

Does it support Modbus?
Yes, via RS-485.

Are PCB numbers available?
No separate PCB numbers are published; the complete relay is normally replaced.

Is it the same as Solcon MPR-6?
It belongs to the same MPR-6 family; compatibility of a specific version must be checked by ordering code.

Are the terminals included?
The pictured unit comes with its plug-in terminal connectors.

Can you ship worldwide?
Yes, from Bangladesh and China.

Short Product Description

The Terasaki MPR-6-DGF (part no. 833831, ordering code MPR6-DGF 1-2-3T-M-M-TE) is a digital motor protection relay for low-voltage motors in marine switchboards and industrial MCCs. Based on true-RMS measurement and a motor thermal model, it provides overload, stall, too-many-starts, jam, short-circuit, under-current, unbalance, earth fault and RTD/thermistor temperature protection with separate alarm and trip levels. An LCD with keypad shows currents, thermal capacity and trip history, and RS-485 Modbus allows remote monitoring. SM MARINE SERVICE™ supplies refurbished MPR-6-DGF relays worldwide, subject to confirmation of condition and availability.

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SM MARINE SERVICE™ – Marine Automation & Navigation Equipment Supplier
Available Equipment Conditions: New • Used • Refurbished • Reconditioned (Specific product condition and availability are subject to confirmation.)
Stock Locations: Bangladesh • China
Services: Worldwide Shipping • Technical Support • Spare Parts Supply • Marine Equipment Sourcing
Samir Market, DT Road, Pahartali, beside CDA Market, Chattogram, Bangladesh
Mobile / WhatsApp / Viber: +88 01818 929292
Email: info@smmarineservice.com
Website: https://www.smmarineservice.com/

Contact us today with your relay label photo for a fast quotation on Terasaki MPR-6 motor protection relays.

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