Figure 1: Wiring Diagram for Current Output Models.
Figure 2: Wiring Diagram for 0 to 5 and 0 to 10 VDC Models.
SCALING OUTPUT RANGE
Set the amperage range at a level appropriate for the load. Use the slide switch on
the top of the SCT as shown in Figure 3.
Figure 3: Selection of Output Scaling.
INCREASING/DECREASING MEASURED CURRENT
If the measured current is too low to be detected or is higher than the maximum
current rating of the SCT, use the following methods to increase or decrease
current.
If measured current is too low to be detected:
Wrap the conductor (wire) through the sensing hole and around the SCT body to
produce multiple turns to increase the measured current. Use the below equation to
determine how many wraps are necessary:
: number of turns
: actual current
: measured current
Figure 4: Wind the conductor through the core to increase current sensed.
Use the following formula to determine the new maximum current:
: number of turns
: SCT current rating
: new maximum current
For example, Model SCT10-100 with 4 turns:
, new maximum
current.
If measured current is above ratings of the switch:
Use a 5 A Current Transformer (CT) to reduce the current passing through the SCT.
Run the current transformer secondary wire through the sensing hole. Terminate the
2 secondary wires of the 5 A current transformer to each other, and then install the
5 A current transformer on the monitored conductor.
Figure 5: Use a 5 A current transformer’s secondary
loop to reduce amount of current sensed.
TROUBLESHOOTING
MAINTENANCE/REPAIR
Upon final installation of the Series SCT, no routine maintenance is required. The
Series SCT is not field serviceable and should be returned if repair is needed. Field
repair should not be attempted and may void warranty.
WARRANTY/RETURN
Refer to “Terms and Conditions of Sales” in our catalog and on our website. Contact
customer service to receive a Return Goods Authorization number before shipping the
product back for repair. Be sure to include a brief description of the problem plus any
additional application notes.
Symptom
Series SCT solid state output
does not function
No SCT output at controller
Model
SCT10-100
SCT10-102
SCT20-103
Range
30/60/120 A
30/60/120 A
20/100/150 A
Output
4 to 20 mA
0 to 5 VDC
0 to 10 VDC
Power
Requirements
24 VDC
Self-powered
Self-powered
Max. Continuous
Operating Current
120 A
120 A
150 A
Icr
N
=
Inm
N
Inm
Icr
N
x
Ia
=
Im
N
Ia
Im
Failure to de-rate the current capacity could result in damage to
the Series SCT when using multiple turns to increase the
measured current.
120A
4
=
30.0 A
Action
Verify that the maximum amperage range has not
been exceeded. Voltages or currents above the
rated levels may damage the Series SCT.
SCT10-100:
1. Verify that the loop power between the SCT
terminals and control panel analog input is 18 to
30 VDC.
2. Turn off the monitored load. Disconnect inputs to
the controller. Measure current in the power
supply and SCT output loop with multimeter.
Current should be 4 mA with no load.
3. Check current loop polarity
SCT10-102 and SCT20-103:
1. Check the amperage in the monitored conductor.
2. Check the polarity of the sensor output and the
controller output.
3. Make sure the clamp is fully closed.
4. Measure the voltage across the SCT output
terminals.
©Copyright 2018 Dwyer Instruments, Inc.
FR# 443900-00 Rev. 1
DWYER INSTRUMENTS, INC.
Phone: 219/879-8000 www.dwyer-inst.com
P.O. BOX 373 • MICHIGAN CITY, INDIANA 46361, U.S.A. Fax: 219/872-9057 e-mail: [email protected]
NOTICE
