Temperature Inputs (Temp) - Siemens 7SR105 Rho User Manual

4.8

Temperature Inputs (TEMP)

The thermal status of the motor can be detected through Temperature inputs (RTD). Motor working temperatures
will determine the life of the motor insulation, each occurrence of increased temperature reduces the life of the
motor. The ambient temperature, coolant temperature, Oil temperature, winding temperature and bearing
temperature of the equipment to be thermally protected can be measured by temperature inputs (RTD).
RTD's can be connected to the Temperature inputs of the Relay, which provide actual temperature detected in
motors, generators and even transformers. Normally thermal temperature of motor can be monitored with, two
RTD sensors are used to monitor bearing temperature of the rotary machines and the three RTD sensors are
used to monitor the stator winding temperature and one RTD sensors can be used for ambient temperature
measurement.
The following table shows the temperature values according to the RTD resistance.
Table 4-1 RTD Resistance Vs Temperature
Temperature (ºC) Pt100
-50 80.306
-45 82.290
-40 84.270
-35 86.247
-30 88.221
-25 90.192
-20 92.159
-15 94.124
-10 96.085
-5 98.044
0 100.000
5 101.952
10 103.902
15 105.849
20 107.793
25 109.734
30 111.672
35 113.608
40 115.540
45 117.470
50 119.397
55 121.320
60 123.241
65 125.159
70 127.075
75 128.987
80 130.896
85 132.803
©2018 Siemens Protection Devices
Pt250 Pt1000 Ni100
200.765 803.062 74.255
205.725 822.901 76.675
210.676 842.706 79.131
215.619 862.477 81.621
220.554 882.216 84.145
225.480 901.923 86.704
230.399 921.598 89.296
235.310 941.243 91.922
240.214 960.858 94.581
245.111 980.444 97.274
250.000 1000.000 100.000
254.881 1019.527 102.759
259.756 1039.025 105.551
264.623 1058.494 108.377
269.483 1077.935 111.236
274.336 1097.346 114.129
279.182 1116.729 117.055
284.020 1136.083 120.016
288.852 1155.408 123.011
293.676 1174.704 126.040
298.492 1193.971 129.105
303.302 1213.209 132.204
308.104 1232.419 135.340
312.899 1251.599 138.512
317.687 1270.751 141.720
322.468 1289.874 144.966
327.242 1308.968 148.250
332.008 1328.033 151.572
7SR105 Rho and 7SR17 Rho Applications Guide
Ni120 Ni250 Cu10
86.163 185.637 7.104
89.450 191.689 7.297
92.752 197.827 7.490
96.070 204.053 7.683
99.406 210.364 7.876
102.767 216.760 8.069
106.149 223.241 8.262
109.560 229.805 8.455
113.002 236.453 8.648
116.481 243.185 8.841
120.000 250.000 9.035
123.561 256.897 9.228
127.167 263.878 9.421
130.819 270.943 9.614
134.518 278.091 9.807
138.264 285.323 10.000
142.059 292.639 10.193
145.904 300.040 10.386
149.800 307.527 10.579
153.747 315.101 10.772
157.745 322.762 10.965
161.796 330.511 11.159
165.900 338.350 11.352
170.057 346.280 11.545
174.268 354.301 11.738
178.532 362.416 11.931
182.848 370.625 12.124
187.218 378.931 12.317
Chapter 7 Page 28 of 31