littelfuse Motor and Pump Protection Relays
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The 777 is a fully programmable electronic overload relay designed to protect any motor drawing 2-800 full load amps (external CTs are required above 90 amps). The 777 (family of products) is for 3-phase 200-480VAC applications, with several specialized units for other voltage ranges and unique applications. Common applications include conveyor systems, HVAC equipment, saws and grinders, fan motors, and almost any pumping application. Some unique applications include use with a Subtrol® equipped Franklin submersible motor to detect high motor temperatures and applications where a fast linear trip is required.

All of the overload relays provide unsurpassed protection by combining overload, voltage, phase loss and reversal, voltage and current unbalance, power monitoring, and underload based on current in one package. For standalone applications, the units incorporate a 3-digit LED display that is used for programming, providing real-time operational information and displaying diagnostic codes to aid in troubleshooting a fault condition. The units also feature a communications port that can be used with communication modules listed in the 777 accessories section to form a Modbus, DeviceNet™, Profibus, or Ethernet network. Up to 99 units can be remotely monitored and controlled from a PC, PLC, or SCADA system, and data logging through a PC with the optional Solutions software. This capability allows for a simple, cost-effective way to meet new requirements for arc-flash safety.

Property (Mouseover for details) Value
Input Voltage (V) 190 to 480VAC
Maximum Input Power 10W
Input AC Line Frequency (Hz) 50/60Hz
Output Form SPDT - Form C
Output Load Rating (VA) Pilot Duty: 480VA @ 240VAC B300; General Purpose: 10A @ 240VAC
Full Load Amp Range (A) 2 - 25A 3 phase (loops required); 25 - 90A 3 phase (direct); 80 - 800A 3 phase (external CTs)
Timing Accuracy (%) 5% ±1s
Rapid Cycle Timer (s) 2 - 500s
Restart Delay Range 2 - 500m or A (Automatic)
Repeat Accuracy (%) Voltage: ±0.5% of nominal voltage; Current: ±1% (<100 amps direct)
Voltage Accuracy (%) ±1%
Overcurrent Trip Point (20A - 100A) … MULT of 80 - 140% of CT primary
Overcurrent Trip Class 5 J5 10 J10 15 J15 20 J20 30 J30
Current Unbalance Trip Point (%) 2 - 25% or 999 (disabled)
Current Unbalance Trip Delay (s) % over setpoint / Trip time: 1% / 30s; 2% / 15s; 3% / 10s; 4% / 7.5s; 5% / 6s; 6% / 5s; 10% / 3s; 15% / 2s
Current Accuracy (%) ±3% (<100 amps direct)
Ground Fault Accuracy (%) ±15%
Sensor Hole Size Max conductor size: 0.65 in (with insulation)
HP/kW Accuracy (%) ±3%
Short Circuit (kA) 100kA
Surge Protection IEC: 61000-4-5 Level 3 2kV line-to-line; Level 4 4kV line-to-ground
Protection Class IP20
Pollution Degree 3
Address A01 - A99 or OP1
Life Electrical: 1 x 105 operations at rated load; Mechanical: 1 x 106
Termination Type Torque: 7in-lbs
Mounting Method Surface mount (4 - #8 screws) on DIN rail mount
Operating Temperature -20° to 70°C (-4° to 158°F)
Storage Temperature (F/C) -40° to 80°C (-40° to 176°F)
Humidity 10-95% non-condensing per IEC 68-2-3
Dimensions 3.05 H x 3.85 W x 5.05 D in. (77.5 x 97.8 x 128.3 mm)
Weight (lbs/g) 1.56 lbs. (25.0 oz. 707.6 g)