777 Series

3-Phase Current & Voltage Monitor

Littelfuse 777 Series 3-Phase Current & Voltage Monitor 500x500

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Description

The 777 unit is an electronic overload relay that can be fully programmed and is intended to safeguard motors drawing between 2 and 800 amps at full load (after 90 amps, external CTs are needed). The 777 product family comprises multiple specialised units for specific voltage ranges and applications, and is utilised for three-phase, 200-480 V ac applications. Conveyor systems are among the common applications.

Fan motors, saws, grinders, HVAC equipment, and nearly any pumping application. Detecting high motor temperatures with a Franklin submersible motor equipped with Subtrol* and applications requiring a quick linear trip are two examples of novel uses.


Features & Benefits

  • Built-in display

    Visual indication for programming, viewing real-time voltage or current, and last fault code.

  • Programmable voltage and current settings

    Allows usage on wide range of systems.

  • 3 selectable restart options

    Choose from automatic, semi-automatic, or manual to best meet individual application needs.

  • 3 programmable restart delay timers

    Program separate restart delay time for rapid cycle protection, motor cool down, and dry-well recovery.

  • Remote display compatibility

    Increases safety through remote display of real-time data and fault history without the need to open the cabinet. Aids with arc flash safety regulations.

  • Flexible reset 

    Reset can be done through a push button on the relay or remotely with optional 777-MRSW or OL-Reset remote reset kit.


777 Series Datasheet

777-P2 User Manual

777-FT User Manual

Specifications

Functional Characteristics

  • Frequency: 50/60 Hz
  • TC- Overcurrent Trip Class(777 Plus Series units): 02-60, J02-J60, L00-L60 or Off
  • TC- Overcurrent Trip Class (77C, 777 non-Plus Series units): 5, 10, 15, 20, 30 (J prefix enables jam protection feature)


Output Characteristics

  • Pilot duty rating: 480 VA @ 240 V ac, B300
  • General purpose: 10 A @ 240 V ac 
  • Pilot duty rating for HVR models: 470 VA @ 600 V ac, B600

 

General Characteristics

  • Operating: -20 °C to 70 °C (-4 °F to 158 °F)
  • Storage: -40 °C to 80 °C (-40 °F to 176 °F)


Accuracy

  • Voltage: ±1 %
  • Current: ±3 % (<100 amps direct)
  • GF Current: ±15 %
  • Timing (777 Plus Series units): ±0.5 second
  • Timing (77C, 777 non-Plus Series units): 5 % +1 second

 

Repeatability

  • Voltage: ±0.5 % of nominal voltage
  • Current: ±1 % (<100 amps direct)
  • Maximum Input Power: 10 W
  • Pollution Degree: 3
  • Class of Protection: IP20
  • Relative Humidity: 10–95 %, non-condensing per IEC 68-2-3
  • Terminal Torque: 7 in.-lbs.

 

Standard Passed

  • Electrostatic Discharge (ESD): IEC 61000-4-2, Level 3, 6 kV contact, 8 kV air
  • Radio Frequency Immunity (RFI), Conducted: IEC 61000-4-6, Level 3, 10 V/m
  • Radio Frequency Immunity (RFI), Radiated: IEC 61000-4-3, Level 3, 10 V/m
  • Fast Transient Burst: IEC 61000-4-4, Level 3, 3.5 kV input power
  • Short Circuit: 100 kA

 

Surge

  • IEC: 61000-4-5, Level 3, 2 kV line-to-line; Level 4, 4 kV line-to-ground
  • ANSI/IEEE: C62.41 Surge and Ring Wave Compliance to a level of 6 kV line-to-line
  • Hi-potential Test: Meets UL508 (2 x rated V +1000 V for 1 minute)
  • Vibration: IEC 68-2-6, 10–55 Hz, 1 mm peak-to-peak, 2 hours, 3 axis
  • Shock: IEC 68-2-27, 30g, 3 axis, 11 ms duration, half-sine pulse
  • Maximum Conductor Size (with insulation) through 777/77C: 0.65” 
  • Dimensions: H 77.47 mm (3.05”); W 97.79 mm (3.85”); D 128.27 mm (5.05”)
  • Weight: 1.56 lbs. (24.96 oz., 707.6 g)
  • Mounting Method: Surface mount (4 - #8 screws) or DIN-rail mount


Ordering Information

MODELLINE VOLTAGEMOTOR FULL AMP RANGE MOTORDESCRIPTION
777-P2200-480 V ac2–800 A (external CTs required above 90 A)Provides low and high power trip*, linear overcurrent trip, and 480 VA @ 240 V ac output SPDT relay contacts.
777-FT200–480 V ac2–800 A (external CTs required above 90 A)Provides linear overcurrent trip and 480 VA @ 240 V ac output SPDT relay contacts.


Accessories

S485MS-2W Communication Module 
(for limited Modbus capabilities) Required to enable the Modbus communications function on Model 77X-type products.

CIO-MB/CIO-120-MB Communication Module
Modbus-RTU interfaces capable of providing discrete control and monitoring of an overload relay over a Modbus network.

CIO-DN-P/CIO-120-DN-P Communication Module 
DeviceNet* interfaces capable of providing discrete control and monitoring of motor starters, drives and other devices over a DeviceNet* network.

CIO-777-PR Communication Module
Profibus interface capable of providing discrete control and monitoring of motor starters, drives and other devices over a Profibus network.

CIO-EN (non-POE) Communication Module
Modbus-TCP and Modbus-RTU interface capable of providing discrete control and monitoring of an overload relay over a Modbus network.

Communication Adapters 

  • RS485-RS232–Converter with cable & plug
  • RS485-USB–Converter with cable & plug
  • RS232-USB–Converter

Specifications match industry standard.

RM1000 Remote Monitor
The RM1000/777 motor management system combines unsurpassed electronic motor protection and critical, user-friendly, motor monitoring for up to 16 devices.

RM2000 Remote Monitor
The RM2000/777 motor management system combines unsurpassed electronic motor protection and critical, user-friendly, motor monitoring with event storage and real-time clock for date and time stamp.

Solutions Software: Solutions-M
Software features include data logging, real-time data monitoring and fault and event monitoring.

777-MRSW Manual Remote Reset Kit
Allows the 777 line of MotorSaver® and PumpSaver® products to be manually reset without opening the panel door.

OL-Reset Manual Remote Reset Kit
Allows the 777 line of MotorSaver® and PumpSaver® products to be manually reset without opening the panel door.



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Featured Case Study

Smart Relay Creates Safety & Efficiency Boom

A large oil & gas exploration company made what is expected to be one of the biggest oil and gas discoveries of the decade in the Permian region’s western part of Texas. The company began evaluating several brands of protection relays to protect their investments in pumps and motors, optimise productivity, and improve safety. After the company’s engineers tried the Littelfuse Bluetooth® Overload Relay MP8000, the search was over.

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Top FAQs

The MP8000 has a wide voltage and current range and operates on 50/60 Hz to protect any motor or pump.

It can also be used to retrofit older current-only based electronic overloads.

It can operate between 90-690VAC and 0.5-1,000A.

Traditional relays require the user to open the electrical cabinets (where relays are typically installed) panel door to use the relay, whether it’s to modify the settings, or to review the cause of a trip event. 

Opening the panel door exposes the worker to shock hazards. Bluetooth, however, enables remote access to these settings, metering and data log information which prevents personnel from unnecessarily having to open the door, thus less exposure to risks.

  • Overload (Overpower) (49)
  • Underload (Underpower) (37P)
  • Overcurrent (51)/Jam
  • Undercurrent (37)
  • Current Unbalance/Phase Loss (46)
  • Phase Reversal (47)
  • Overvoltage (59)
  • Undervoltage (27)
  • Voltage Unbalance (47)
  • Rapid Cycling/Jog
  • Contactor Failure
  • Zero-Sequence Ground Fault (50Ns)
  • PTC Motor Overtemperature (49)

The MP8000 can be used in both single phase and 3 phase applications.

Yes, the MP8000 can be put into current-only mode which will disable voltage-based protection functions. However, Littelfuse strongly recommends utilizing the voltage-based protection functions for superior protection especially prior to motor startup.

The current-only mode is intended for retrofit applications on voltages above 690 VAC.


The MP8000 can be surface or panel mounted, or installed on a DIN rail.

No, the MP8000 uses Bluetooth to connect to your smart phone or tablet via the Littelfuse app, This enhances the users safety as it allows remote access.

Yes, you can access the information remotely through the Littelfuse MP8000 PC software or through other software programs communicating with the MP8000 through the Ethernet interface. Contact Fuseco for information on how to download this software.

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Applicable Industries

Hi Tim, just wanted to thank you and the Fuseco team for your help. You've managed to help us solve some nagging issues here and the Littelfuse SE-330AU relay installation has saved us a lot of time. Thanks!

Mark Sherman

PGS Silver, Queensland

Just wanted to send a note of thanks to you guys. When it comes to relays, your advice & service is high level & appreciated. Cheers.

Jesse Marshall

Newcrest WA

The Littelfuse SE-701 & the CT's are functioning well. Thanks guys, really appreciate your help. Good to work with people you can rely on.

Cliff Peligro

Alpha Coal, Queensland

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