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26 Rockwell Automation Publication 150-QS003D-EN-P - November 2013
Chapter 2 Installation
PTC Thermistor Sensors
The 150-SM2 option module allows the SMC-50 to interface with motor PTC
sensors to monitor motor temperature. The following table defines the PTC
input and response ratings.
Table 8 - PTC Input & Response Ratings
Figure 17 - Combined Wiring Diagram of All Cat. No. 150-SM2 Sensors
➊
Customer-supplied.
➋ The 825-MCM can be used with or without an external bypass contactor. If an external bypass contactor is used
then the 825-MCM must be installed in order to use current-based motor protective features including the
motor overload feature. Cable length is 4 meters. Only the cable provided with the 825-MCM is compatible
with the 150-SM2.
➌ The 825-CBCT core balance sensor mounts separately from the SMC-50 and must be placed within 3 meters of
the SMC-50. When connecting the 825-CBCT ground-fault sensor, the secondary of the CT must be shorted until
connection to the 150-SM2 module is complete.
➍ See the user manual for additional bypass configurations (e.g., emergency run-off bypass) and application
considerations.
➎ To meet product susceptibility requirements, a single ferrite core must be placed around any or all sensor (e.g.,
PTC, ground fault, etc.) wires connected to the 150-SM2 Option Module. The recommended core is a Fair-Rite
Products Corp Part Number 0431167281 or equivalent.
➏ Ensure the 150-SM2 Turns Ratio, Parameter X.5, is configured to match the 825-CBCT Turns Ratio 100:1
(X.5=100).
Response Resistance
3400
Ω ± 150 Ω
Reset Resistance
1600
Ω ± 100 Ω
Short-Circuit Trip Resistance
25
Ω ± 10 Ω
Maximum Voltage at PTC Terminals
R
PTC
= 4 KΩ < 7.5V
R
PTC
= open
30V
Maximum Number of Sensors Connected in Series 6
Maximum Cold Resistance of PTC Sensor Chain
1500
Ω
Response Time 800 ms
RG25U
Female
TB4
TB4
TB3
TB3
TB2
TB2
150-SM2 Module Circuit Board
RG25U
Male
1
1
2
2
Shield
To Control
Module
Terminal #3
Ground
Shield
T1/2
T2/4
T3/6
L1/1
L2/3
L3/5
SMC-50
Fast-Acting SCR
Fuses (optional)
External Bypass
825-CBCT
Core Balance
Ground Fault
Sensor
Circuit
Branch
Protection
Motor PTC
Sensor Cable
825-MCM Cable
825-MCM
Shield
White
Black
M
1
1 2
1 2
1
1
1 4
1 3
5
6
1