Protection Relays
Current Monitoring Relays and Transducers
LSRU SERIES
Load sensor
Description
The LSRU Series 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.
Wiring Diagram
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.
Features & Benefits
FEATURES
BENEFITS
LED indicator
Visual indication of relay status
Eliminates the need for a stand alone current
transformer and also provides isolation between the
monitored and control circuits
Built in current sensor
Adjustable current
sensing range
Provides ability to precisely set the current trip point
for any application
Ordering Information
See next page.
© 2016 Littelfuse Protection Relays & Controls
www.littelfuse.com/lsru
Rev: 1-A-062716