LSRU-115-FC-1.5 - LSRU Series

Series: LSRU Questions? Contact Littelfuse Support
Littelfuse Current Monitoring Relays Transducers
The LSRU is a microcontroller-based family of load sensors. The LSRU family of products employ three basic types of control logic: motor control logic, alarm logic and feed control logic.


Motor Control Logic
Several combinations of functions are available in the LSRU, including overcurrent and undercurrent or either overcurrent or undercurrent with variable trip, restart or extended restart delay settings. These various versions of the LSRU trip on the respective fault and then automatically reset after the restart delay expires, in preparation for the next motor start. LSRUs do not trip on undercurrent when the load turns off, this is recognized as a normal condition.
Alarm Logic
The LSRU-AL simply indicates whether the current is between the setpoints or outside of the setpoints. This product is best used with a PLC or other controller where status indication is desired.
Feed Control
The LSRU-FC is a load monitor intended to control feeder mechanisms in a variety of applications. It stops the feeder when the grinder, chipper, saw, auger, etc. nears overload. When the load is reduced to a preset level, the feeder is restarted.

Property (Mouseover for details) Value
Input Voltage (V) 18 - 30VAC
Output Form SPDT
Output Load Rating (VA) Pilot Duty: 480VA @ 240VAC; General Purpose: 10A @ 240VAC
Timing Accuracy (%) ±10%
Current Accuracy (%) ±2%
Current Sensor Range 5 to 25A
Sensor Hole Size 0.725 in diameter
Control Type Feed control
Motor Acceleration Time Operating Point (s) 2s
Power Consumption ≤2W
Isolation Voltage (V) 600VAC rms
Termination Type Torque: 7 in.-lbs.; Wire: 12-24AWG
Mounting Method Surface mount; Four #6 screws 3/4 in in length
Operating Temperature -40° to 70°C (-40° to 158°F)
Humidity 50/60Hz
Dimensions 1.67î H x 2.30î W x 3.56î D (42.4 x 58.4 x 90.4 mm)
Weight (lbs/g) 0.5 lb. (8.0 oz. 226.8 g)