S5 THERMAL MODEL 4. SETPOINT PROGRAMMING
4-30
Table 4-2 SR469 STANDARD OVERLOAD CURVES
PICKUP
STANDARD CURVE MULTIPLIERS
LEVEL
(x FLA)
x 1 x 2 x 3 x 4 x 5 x 6 x 7 x 8 x 9 x 10 x 11 x 12 x 13 x 14 x 15
1.01 4353.6 8707.2 13061 17414 21768 26122 30475 34829 39183 43536 47890 52243 56597 60951 65304
1.05 853.71 1707.4 2561.1 3414.9 4268.6 5122.3 5976.0 6829.7 7683.4 8537.1 9390.8 10245 11098 11952 12806
1.10 416.68 833.36 1250.0 1666.7 2083.4 2500.1 2916.8 3333.5 3750.1 4166.8 4583.5 5000.2 5416.9 5833.6 6250.2
1.20 198.86 397.72 596.58 795.44 994.30 1193.2 1392.0 1590.9 1789.7 1988.6 2187.5 2386.3 2585.2 2784.1 2982.9
1.30 126.80 253.61 380.41 507.22 634.02 760.82 887.63 1014.4 1141.2 1268.0 1394.8 1521.6 1648.5 1775.3 1902.1
1.40 91.14 182.27 273.41 364.55 455.68 546.82 637.96 729.09 820.23 911.37 1002.5 1093.6 1184.8 1275.9 1367.0
1.50 69.99 139.98 209.97 279.96 349.95 419.94 489.93 559.92 629.91 699.90 769.89 839.88 909.87 979.86 1049.9
1.75 42.41 84.83 127.24 169.66 212.07 254.49 296.90 339.32 381.73 424.15 466.56 508.98 551.39 593.81 636.22
2.00 29.16 58.32 87.47 116.63 145.79 174.95 204.11 233.26 262.42 291.58 320.74 349.90 379.05 408.21 437.37
2.25 21.53 43.06 64.59 86.12 107.65 129.18 150.72 172.25 193.78 215.31 236.84 258.37 279.90 301.43 322.96
2.50 16.66 33.32 49.98 66.64 83.30 99.96 116.62 133.28 149.94 166.60 183.26 199.92 216.58 233.24 249.90
2.75 13.33 26.65 39.98 53.31 66.64 79.96 93.29 106.62 119.95 133.27 146.60 159.93 173.25 186.58 199.91
3.00 10.93 21.86 32.80 43.73 54.66 65.59 76.52 87.46 98.39 109.32 120.25 131.19 142.12 153.05 163.98
3.25 9.15 18.29 27.44 36.58 45.73 54.87 64.02 73.16 82.31 91.46 100.60 109.75 118.89 128.04 137.18
3.50 7.77 15.55 23.32 31.09 38.87 46.64 54.41 62.19 69.96 77.73 85.51 93.28 101.05 108.83 116.60
3.75 6.69 13.39 20.08 26.78 33.47 40.17 46.86 53.56 60.25 66.95 73.64 80.34 87.03 93.73 100.42
4.00 5.83 11.66 17.49 23.32 29.15 34.98 40.81 46.64 52.47 58.30 64.13 69.96 75.79 81.62 87.45
4.25 5.12 10.25 15.37 20.50 25.62 30.75 35.87 41.00 46.12 51.25 56.37 61.50 66.62 71.75 76.87
4.50 4.54 9.08 13.63 18.17 22.71 27.25 31.80 36.34 40.88 45.42 49.97 54.51 59.05 63.59 68.14
4.75 4.06 8.11 12.17 16.22 20.28 24.33 28.39 32.44 36.50 40.55 44.61 48.66 52.72 56.77 60.83
5.00 3.64 7.29 10.93 14.57 18.22 21.86 25.50 29.15 32.79 36.43 40.08 43.72 47.36 51.01 54.65
5.50 2.99 5.98 8.97 11.96 14.95 17.94 20.93 23.91 26.90 29.89 32.88 35.87 38.86 41.85 44.84
6.00 2.50 5.00 7.49 9.99 12.49 14.99 17.49 19.99 22.48 24.98 27.48 29.98 32.48 34.97 37.47
6.50 2.12 4.24 6.36 8.48 10.60 12.72 14.84 16.96 19.08 21.20 23.32 25.44 27.55 29.67 31.79
7.00 1.82 3.64 5.46 7.29 9.11 10.93 12.75 14.57 16.39 18.21 20.04 21.86 23.68 25.50 27.32
7.50 1.58 3.16 4.75 6.33 7.91 9.49 11.08 12.66 14.24 15.82 17.41 18.99 20.57 22.15 23.74
8.00 1.39 2.78 4.16 5.55 6.94 8.33 9.71 11.10 12.49 13.88 15.27 16.65 18.04 19.43 20.82
10.00 1.39 2.78 4.16 5.55 6.94 8.33 9.71 11.10 12.49 13.88 15.27 16.65 18.04 19.43 20.82
15.00 1.39 2.78 4.16 5.55 6.94 8.33 9.71 11.10 12.49 13.88 15.27 16.65 18.04 19.43 20.82
NOTE:
Above 8.0 x Pickup, the trip time for 8.0 is used.
This prevents the overload curve from acting as an instantaneous element
Standard Overload Curves Equation:
Time_To_ Trip
Curve_Multiplier 2.2116623
0.025303373 (Pickup 1) 0.050547581 (Pickup 1)
2
=
×
×−+ ×−
CUSTOM OVERLOAD CURVE
If the motor starting current does begin to infringe on the thermal damage curves, it may become necessary to use a custom curve to
tailor the protection to the motor so that successful starting may be possible without compromising motor protection. Furthermore, the
characteristics of the starting thermal damage curve (locked rotor and acceleration) and the running thermal damage curves may not fit
together very smoothly. In this instance, it may become necessary to use a custom curve to tailor the motor protection to the motor
thermal limits such that the motor may be started successfully and the motor may be utilized to its full potential without compromising
protection. The distinct parts of the thermal limit curves now become more critical. For these conditions, it is recommended that the
SR469 custom curve thermal model be used. The custom overload curve of the SR469 allows the user to program his own curve by
entering trip times for 30 pre-determined current levels.
It can be seen in Figure 4-9 that if the running overload thermal limit curve were smoothed into one curve with the locked rotor overload
curve, the motor could not start at 80% line voltage. A custom curve is required.
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