Miniature Adjustable Current Switches
Installation and Operation
#NSA-A/MCS-A, NSA-A/MSCS-A
– 11/14/2019
Specifications subject to change without notice.
Catalog No. 11-808-762-01
Page
5
of
5
Calibration of Adjustable Trip Point
The adjustable current switch has an operating range of 0-150 Amps. Do not exceed! The adjustable current switch comes
with its fifteen-turn adjustment potentiometer set to the 100 Amp trip point position. The adjustable current switch can be
used to monitor Under Load, Normal L
oad, and Over Load conditions, depending on how it’s set. The procedure below is
for the Normal load condition for part numbers NSA-A/MCS-A- and NSA-A/MSCS-A.
Normal Loads
With current flowing through the aperture of the NSA-A/MCS-A and NSA-A/MSCS-A current switches, first verify that the
Blue LED is on. If the Blue LED is on, now slowly adjust the potentiometer clockwise until the Red LED just turns on and
stop immediately. This sets the trip point at your normal operating load current. If the RED LED is on after initial power up,
this means that you need to slowly adjust the potentiometer counter-clockwise until the Blue LED turns on and then slowly
adjust the potentiometer clockwise until the Red LED just turns on and stop immediately. The adjustable current switch is
now tripped. Now verify the output with an Ohmmeter to verify that the contacts of the switch are approximately 0.200
Ohms. The adjustable current switch Hysteresis (Dead Band) is typically 10% of the trip point.
Troubleshooting
Problem
Solution
Red LED is on but the current switch didn’t activate
Disconnect the wires from the current switch output.
Measure the resistance across the contacts with an
Ohmmeter. See the table below for resistance
readings for a good unit.
Red LED didn
’t turn on and the current switch didn’t
activate
Verify that the conductor you are monitoring is above
the adjustable trip point. If the sensor is monitoring
less than the adjustable trip point, see Figure 3
Error!
eference source not found.
.
Sensor doesn't switch at all, regardless of current
level.
Adjustment potentiometer is probably set to its
maximum or minimum position. Turn the Pot counter-
clockwise all the way and verify if the LED switches
from Red to Blue.
Resistance Readings
Carrier Model #
Resistance if switch open
Resistance if switch closed
NSA-A/MCS-A
Greater than 1 Meg ohms
Approximately 0.2 ohms
NSA-A/MSCS-A
Greater than 1 Meg ohms
Approximately 0.2 ohms
W.E.E.E. Directive
At the end of their useful life the packaging and product should be disposed of via a suitable recycling center. Do not
dispose of with household waste. Do not burn.
