Littelfuse 77C-LR-KW/HP Pump Monitor Product Description

The 77C-KW/HP and 77C-LR-KW/HP are fully programmable pump protection relays which will monitor the voltage and current for high or low voltage, overload and underload conditions based on power, in one package. 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 around 3400 rpm and usually have small current vs load changes; such as slow speed mixer or agitator motors up to 50 hp, and magdrive or can pumps. The Littelfuse PumpSaver® relay provides the high sensitivity of a power monitor to protect pump motors from dry run and deadhead conditions.

Small motors, those under 3 hp and especially fractional horsepower, exhibit small changes in current vs. load, but the change in power is large. When larger motors are derated (run below their rated horsepower) the change in current is small vs. load, but again, the change in power is large and linear. Other typical applications include slower speed mixer or agitator motors up to 50 hp and beyond. These motors and others that run slower than around 3400 rpm usually have small current changes vs. load.

The 77C-LR-KW/HP Provides 480 VA @ 240 V ac output SPDT (Form C) relay contacts.

Littelfuse 77C-LR-KW/HP Pump Monitor Typical Application

• Conveyor Systems
• HVAC Equipment
• Saws and Grinders
• Fan Motors
• All Pumping Applications With Single-Phase Electric Motors

Littelfuse 77C-LR-KW/HP Pump Monitor Technical Details

• Protects Single-Phase motors from:
  • Overload
  • Underload
  • Jams
  • Low Voltage
  • High Voltage
  • Rapid Cycling
• Fully Programmable
• Automatic Reset With Three Separate Restart Delay Timers, or Manual Reset
• Tamper Guard
• RS-485 Communications Port (Communications Module Sold Separately)
• 3-digit LED Diagnostic Display
• Remote Reset
• Last Fault Memory
• UL and cUL Listed
• CE Compliant
• CSA Approved
• Surface or DIN Rail Mount
• 5-year Warranty
• Made in USA

Littelfuse 77C-LR-KW/HP Pump Monitor Specifications

Input Voltage . . . . . . . . . . . . . . . . . . . . . 100-240 VAC, 1Ø

Frequency . . . . . . . . . . . . . . . . . . . . 50/60Hz

Motor Full Load Amps

• . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-25 Amps, 3Ø(Loops Required)
• . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-90 Amps, 3Ø(Direct)
• . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91-800 Amps, 3Ø(External CT’s)

Short Circuit Withstand Rating . . . . . . . . . . . 100kA per UL and CSA

Power Consumption . . . . . . . . . . .5W (Maximum)

Output Contact Rating

Expected Life

Accuracy at 25° C (77° F)

Repeatability

Safety Marks

Electorstatic Discharge (ESD) . . . . . . . . . IEC 61000-4-2, Level 3, 6kV contact, 8kV air

Radio Frequency Immunity (RFI), Conducted . . . . . . . . .IEC 61000-4-6, Level 3 10V/m

Radio Frequency Immunity (RFI), Radiated . . . . . . . . .IEC 61000-4-3, Level 3 10V/m

Fast Transient Burst . . . . . . . . .IEC 61000-4-4, Level 3, 3.5kV input power

Surge

Terminal Torque . . . . . . . . . . . . . . . . . . 7 in.-lbs

Enclosure Material . . . . . . . . . polycarbonate

Weight . . . . . . . . . . . . . . . . . . . . . . . . 1.2 lbs<

Temperature Range

Class of Protection . . . . . . . . . . . . . . . . . . . . IP20, NEMA 1

Relative Humidity . . . . . . . . . . . . . . . . . . . . . 10-95%, non-condensing per IEC 68-2-3

Programable Operating Points

* If J Prefix is displayed in trip class setting, jam protection is enabled. If programmed to Lin position, overcurrent trip delays are fixed linear-type delays set in OPT1 position

WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov

Littelfuse 77C-LR-KW/HP Pump Monitor Resources

Littelfuse 77C-LR-KW/HP Product Specifications

Littelfuse 77C-LR-KW/HP Installation Bulletin

Littelfuse 77C-LR-KW/HP Engineering Specifications