Adjustable Current Switches
Installation and Operation
#NSA-A/ACS2, NSA-A/ASCS2, NSA-A/ASCS2-L
– 11/14/2019
Specifications subject to change without notice.
Catalog No. 11-808-743-01
Page
7
of
7
Application Examples
See Figure 5 and Figure 6 for two different current switch applications. Figure 5 shows the use of the Go/No Go Current
Switch as a Digital Input to your BAS/PLC Controller. Figure 6 shows a Go/No/Go Current Switch in conjunction with a
Contactor to control an exhaust fan.
NOTE
The Go/No Go Current switches are only rated at 0.2A @ 200 VAC/VDC and must use an additional Contactor if
controlling motor/fans.
Calibration of Adjustable Trip Point
The adjustable current switch has an operating range of 0-250 Amps,
Do not exceed!
The current switch has an
adjustable trip point range of 0.50 - 220 Amps, 1.50 - 220 Amps, or 0.60 - 180 Amps depending on the model. See the
Specifications table to determine the adjustable trip point range per model number. The adjustable current switch comes
with its fifteen-turn adjustment potentiometer set to the maximum trip point position. The adjustable current switch can
monitor Underload, Normal Load, and Overload conditions, depending on how it’s set. The procedure below is for the
Normal load condition for part numbers NSA-A/ACS2, NSA-A/ASCS2 and NSA-A/ASCS2-L.
Normal Loads
With power on, turn the 15-turn adjustment potentiometer clockwise until the Red LED turns on and stop immediately.
Clockwise is referenced with the terminal block location on the right. The adjustable current switch is now tripped. The
adjustable current switch Hysteresis (Dead Band) is 10% of the trip point typically.
Clockwise = Decrease Trip
Counter-clockwise = Increase Trip
Troubleshooting
Problem
Solution
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 Specifications table for the actual
resistance readings for an open or closed switch reading.
LED
didn’t turn on and the current switch didn’t
activate
Verify that the current flowing in the conductor being
monitored is above the fixed trip point as listed in the
operating specifications. If the sensor is monitoring less
than the fixed trip point, see Figure 3.
LED not on but the Current Switch is Activated
LED not indicating correctly, may have been damaged.
Current Switch is operating at a low-level current or
failing to operate within the accuracy specifications
For NSA-A/ASCS2 Series, visually check the mating parts
of the core to ensure there is no debris between the split
contacts. Remove all debris or dust manually and close
the current sensor, see Figure 2. Retest the sensor in your
application.
