Littelfuse 77C-KW/HP, 77C-KW Series, Single-Phase Current & Voltage Monitor, 100-240VAC, 1 Phase, 2–90 A (external CTs required above 90 A)
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The 77C-KW single-phase relay is part of the 777/77C product family. The 77C-KW, 77C-KW/HP and 77C-LR-KW/HP are fully programmable pump protection relays that monitor for high or low voltage and overload and underload conditions based on power. These overload relays are designed to protect any motor drawing 2–800 full load A (external CTs are required above 90 A). The 777-HVR-SP and 77C are for single-phase 100–240 V ac applications.
All of the overload relays provide unsurpassed protection by combining overload, underload, and voltage in one unit. 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 network 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.
The underpower trip feature is desirable anytime the current vs. load characteristic is non-linear or has little change. In general terms, smaller motors and slow-speed motors have little change in current over the normal load range. Larger motors that are running light loads will also show small current changes over the operating load range. Common uses include pumping applications where motors run slower than 3400 rpm and usually have small current versus load changes, such as slow speed mixers or agitator motors up to 50 hp, mag-drives, or can pumps.
Note: The Littelfuse PumpSaver® relay provides the high sensitivity of a power monitor to protect pump motors from dry run and dead head conditions.
Applications
• Conveyor systems
• HVAC equipment
• Saws and grinders
• Fan motors
Specifications
| Input Voltage | 100–240 V ac, 1Ø |
| Frequency | 50–60 Hz |
| Motor Full Load Amp Range | |
| 77C-KW/HP | 2–25 A (loops required); 26–90 A (direct); 91–800 A (external CTs) |
| 77C-LR-KW/HP | 1.0 A - 2.0 A (additional loop); 2.0 A - 9.0 A (direct) |
| Short Circuit Withstand Rating | 100 kA per UL and CSA |
| Power Consumption | 5 W (Maximum) |
| Output Contact Rating SPDT (Form C) |
Pilot duty rating: 480 VA @ 240 V ac General purpose: 10 A @ 240 V ac |
| Expected Life |
Mechanical 1 x 106 operations Electrical 1 x 105 operations at rated load |
| Accuracy at 25 °C (77 °F) |
Voltage ±1 % Current ±3 % (Direct, No External CTs) Timing 5 % ± 1 second |
| Repeatability |
Voltage ± 0.5 % of nominal voltage Current ± 1 % (Direct, No External CTs) |
| Standards 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 Radiated IEC 61000-4-3, Level 3 10 V/m |
| Fast Transient Burst | IEC 61000-4-4, Level 3, 3.5 kV input power |
| Surge | |
| IEC | 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 UL 508 (2 x rated V +1000 V for 1 min.) |
| Vibration | IEC 68-2-6, 10-55 Hz, 1 mm peak-to-peak, 2 hours, 3 axis |
| Shock | IEC 68-2-27, 30 g, 3 axis, 11 ms duration, half-sine pulse |
| Mechanical | |
| Dimensions |
H 78.74 mm (3.1”) W 99.06 mm (3.9”) D 129.54 mm (5.1”) |
| Terminal Torque | 7 in.-lbs. |
| Enclosure Material | Polycarbonate |
| Weight | 1.2 lbs |
| Maximum Conductor Size Through 777 | 0.65” with insulation |
| Environmental | |
| Temperature Range |
Ambient Operating -20 °C–70° C (-4 °F–158 °F) Ambient Storage -40 °C–80° C (-40 °F–176 °F) |
| Pollution Degree | 3 |
| Class of Protection | IP20, NEMA 1 |
| Relative Humidity | 10–95 %, non-condensing per IEC 68-2-3 |
| Programmable Operating Points | Range |
| LV- Low Voltage Threshold | 85 V - HV Setting |
| HV- High Voltage Threshold | 264 V - LV Setting |
| MULT- # of Conductors or CT Ratio (XXX:5) |
77C: 1–10 Conductors or 100-800 Ratio 77C-LR: 1 or 2 |
| OC- Overcurrent Threshold | (20–100 A) ÷ MULT or 80–120 % of CT Primary |
| TC- Overcurrent Trip Class* | 5, J5, 10, J10, 15, J15, 20, J20, 30, J30, or LIn (linear) |
| RD1- Rapid Cycle Timer | 0, 2–500 seconds |
| RD2- Restart Delay After All Faults Except Undercurrent (motor cool down timer)** | 2–500 minutes/seconds |
| RD3- Restart Delay After Undercurrent (dry well recovery timer) | 2–500 minutes/seconds |
| #RU- Number of Restarts | |
| After Undercurrent | 0, 1, 2, 3, 4, A (Automatic) |
| ADDR- RS485 Address | A01- A99 |
| #RO-Number of Restarts | |
| After Overcurrent | 0, 1, 2, 3, 4, A (Automatic) |
| LP/PWS (PWS = LP Range) |
1 = 0.01 - 0.99 KW 2 = 1.00 - 9.95 KW 3 = 10.0 - 99.5 KW 4 = 100 - 650 KW 5 = 0.01 - 1.30 HP 6 = 1.34 - 13.3 HP 8 = 13.4 - 133 HP 9 = 134 - 871 HP |
| Certification & Compliance |
UL UL508, UL1053 (File #E68520) CSA C22.2 CE IEC 60947-1, IEC 60947-5-1 |