Dwyer Instruments SCT10-100 User manual

Bulletin PC-SCT
The Series SCT Current Tr nsformers continuously measure the current
consumption of pumps, fans, boilers, solar panels and chillers for use in energy
monitoring. Current or voltage outputs can be scaled using a slider switch to select
between three factory set ranges. Split core configuration allows the current transformer
to be installed on new and existing installations. Snap-on mounting bracket allows
for quick installation of replacement transformers. An optional 10 A command relay
can snap onto the current switch which eliminates the need to mount an additional
relay.
OPERATING INSTRUCTIONS
INSTALLATION
MOUNTING
1. Detach the plastic mounting bracket from the current switch housing.
2. Using the two included screws, attach the mounting bracket to the rear of the
electrical panel or enclosure.
3. Re-attach the current switch housing to the plastic mounting bracket.
WIRI G
1. Disconnect the power to the conductor cable from the power source.
2. Open the core using the release tab. Snap the core closed around the power
conductor cable. Make sure that the core release tab is locked in its original
position.
3. Wire the Series SCT as shown in the below wiring diagrams.
4. Reconnect the power conductor cable.
Specific tions - Inst ll tion nd Oper ting Instructions
Series SCT Current Tr nsformer
SPECIFICATIONS
Amper ge R nge: 30/60/120 A or 20/100/150 A (depending on model).
Continuous Oper ting Current: 120 A or 150 A (depending on model).
Output: 4 to 20 mA, 0 to 5 VDC, 0 to 10 VDC (depending on model). Optional
relay .O. SPST; 10 A @ 260 VAC, 5 A @ 30 VDC.
Power Requirements: Self-powered or 24 VDC (depending on model).
Accur cy: ±2% from 10 to 100% of selected range.
Temper ture Limits: 5 to 140°F (-15 to 60°C).
Humidity Limits: 0 to 95% non-condensing.
Response Time: 2 seconds.
Isol tion Volt ge: 600 VAC RMS.
Frequency: 50/60 Hz.
Enclosure R ting: UL, V-O flammability rated, type 66 nylon.
Agency Approv ls: CE, RoHS, UL.
Disconnect the power supply before making electrical
connections. Contact with components carrying hazardous
voltage can cause electrical shock and may result in severe personal injury or
death.
CAUTION
DWYER INSTRUMENTS, INC. Phone: [phone] www.dwyer-inst.com
P.O. BOX 373 • MICHIGAN CITY, INDIANA 46361, U.S.A. Fax: [phone] e-mail: [e-mail]
ModelSC T10-100
Analog Current Transducer
Read instructions
before installing
Isolation 600VAC (UL)
300 VAC(CE)
[phone]
www.dwyer-inst.com
3BYE
IND.CONT. CO.
Class 2
C223444
1-1/16
[26.9] 2-9/16
[65.0]
43/64
[17]
SNAP ON RELAY
MOUNTING BRACKET
2-9/16
[65.0]
2-45/64
[68.6] 13/64
[5.3]
3/8
[9.6]
3-1/4
[82.4]
2-45/64
[68.6]
The Series SCT Current Transformers are intended to provide
an input to equipment under normal operating conditions.
Additional precautions must be designed into the control system where failure or
malfunction of the current transformer could lead to personal injury or property
damage to the controlled equipment or other property. Incorporate and maintain
other devices such as supervisory, alarm systems, safety or limit controls intended
to warn of or protect against failure or malfunction of the SCT.
NOTICE

Figure 1: Wiring Di gr m for Current Output Models.
Figure 2: Wiring Di gr m for 0 to 5 nd 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 me sured 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 incre se 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 me sured current is bove r tings 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 5 A current tr nsformer’s second ry
loop to reduce mount 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
o SCT output at controller
Model
SCT10-100
SCT10-102
SCT20-103
R nge
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
M x. Continuous
Oper ting Current
120 A
120 A
150 A
Icr
N=Inm N
Inm
Icr
N xIa =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: [phone] www.dwyer-inst.com
P.O. BOX 373 • MICHIGAN CITY, INDIANA 46361, U.S.A. Fax: [phone] e-mail: [e-mail]
NOTICE