520CS115 - 520CS / 520CP Series

Littelfuse Current Monitoring Relays Transducers
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The 520CS and 520CP are fully-programmable, microcontroller-based, current-sensing devices designed to monitor 3-phase pumps. The 520CP is designed to work with motors that have ramp-up times of 4 seconds or less. The 520CS has a programmable motor acceleration time that can be set from 0-50 seconds.

Both current monitors protect 3-phase motors from:

  • Overcurrent
    • Undercurrent
      • Current Unbalance
        • Rapid Cycling
          • Single Phasing
            • Phase Reversal
Property (Mouseover for details) Value
Input Voltage (V) 100 to 130VAC
Maximum Input Power 5W
Input AC Line Frequency (Hz) 50/60Hz (50Hz will increase all delay timers by 20%.)
Input Current Range (A) 5 Amps (maximum)
Output Form SPDT
Output Load Rating (VA) Pilot Duty: 480VA @ 240VAC; General Purpose: 10A
Timing Accuracy (%) 25%
Rapid Cycle Timer (s) 0 - 500s; Programmable number of restarts; 0, 1, 2, 3, 4 or 999 for unlimited
Restart Delay Range On power up: 0 - 500s; after all faults: 2 - 500m
Trip Delay Range 2 - 50s for all faults except phasing faults
Trip Point Accuracy (%) ±2%
Overcurrent Trip Point Undercurrent trip point to 5A
Undercurrent Trip Point 0.00 to overcurrent trip point
Current Unbalance Trip Point (%) 2 - 50%
Reverse and Single Phase Trip Delay (s) 0.5s
Motor Acceleration Time Operating Point (s) 0 - 50s
Mounting Method Four #10 or #12 screws (3/4 in - 1 in in length)
Operating Temperature 0° to 70°C (32° to 158°F)
Dimensions 8.25 in H x 5.25 in W x 3.25 in D (209.6 x 133.4 x 82.6 mm)
Weight (lbs/g) 2.2 lbs. (35.2 oz. 997.9 g)