Rockwell Automation 1560E SMC Flex Smart Motor Controller - Manual (Page 25)

Product Overview 1-15
Table 1.A – PTC Input Ratings
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 k Ω) < 7.5 V
Maximum Voltage at PTC Terminals (R
PTC
= open) 30 V
Maximum Number of Sensors 6
Maximum Cold Resistance of PTC Sensor Chain 1500 Ω
Response Time 800 ms
The following figure illustrates the required PTC sensor characteristics,
per IEC-34-11-2.
10
20
4000
250
100
550
1330
TNF-20K
TNF- 5K
-20° C
0°C
TNF
TNF+ 5K
TNF+15K
10
20
4000
250
100
550
1330
10
20
4000
250
100
550
1330
10
20
4000
250
100
550
1330
TNF-20K
TNF- 5K
-20° C
0°C
TNF
TNF+ 5K
TNF+15K
Figure 1.13 – PTC Sensor Characteristics per IEC-34-11-2
PTC Trip
The MV SMC-Flex will trip with a PTC indication if:
• No other fault currently exists
• PTC protection is enabled
• The resistance across terminals 23 and 24 is either greater than the
relay’s response resistance or less than the short-circuit trip resistance.