What are the 5 control terminals on the LH4N225QN7 for?


01 March 2021

The LH4-N2 devices rated 25 amps and below are provided with control terminals 01
to 05. Terminals 01, 02, and 03 are used to provide the user with a choice of
freewheel or soft stop. In order to begin the soft start ramp, both line voltage and a
connection from terminals 01 to 03 must be present. The start signal may be
maintained—as shown when soft stop is not required—or instantaneous, as shown
for control with soft stop.

A normally open seal in / fault relay is provided between terminals 04 and 05. These
terminals should be used to keep the line contactor energized after a stop command
for the duration of the soft stop ramp or to drop out the line contactor if the soft start
module is damaged. The LH4N has internal fault detection only and does not
provide protection from motor or line faults.

Control power for the LH4-N2 devices rated 25 amps and below are provided by an
internally connected transformer. These units can only operate at the line voltage for
which they are rated.