Nema Table; Table A-1 Nema Table 20-1 From Nema Standard Mg-1 1993 Part 20.42 Converted To Si Units - Siemens SINAMICS PERFECT HARMONY GH180 Function Manual

NEMA Table

The inverse time algorithms will only work correctly if the proper Max Motor Inertia is used. If this
is known from the manufacturer, enter this value into parameter "Maximum Motor Inertia" (ID
1159).
If this value is zero, the NXGpro software will attempt to calculate the value based on the "Motor
kW Rating" (1010) and the synchronous speed (based on Motor Frequency (1020) and Full Load
Speed (1030)).
If the values are outside of the range of the NEMA Table 20-1 from NEMA Standard MG-1 in either
HP (kW) or Synchronous Speed, then the maximum value for the synchronous speed column
must be used.
The table below provides the NEMA table values in SI units, converted from lb-ft² to kg-m², for
easier application on the drive. Enter the result into the Maximum Motor Inertia parameter.
The table below was created by converting NEMA Table 20-1 values using the following
calculation:
Load Wk² = A * [Hp
Hp column and converting to kW by multiplying HP * 0.746
Then converting the equivalent inertia from Wk² to SI by dividing lb-ft² by 23.73
Table A-1 NEMA Table 20-1 from NEMA Standard MG-1 1993 Part 20.42 converted to SI units, Maximum Load Inertia for
Polyphase Squirrel-Cage Induction Motors in kg-m²
Hp kW 3600
100 75
125 93
150 112
200 149
250 187
300 224
350 261
400 298
450 336
500 373
600 448 18.7
700 522 21.2
NXGPro+ Control Manual
Operating Manual, A5E50491925A
/ (rpm/1000)
0.95
kW = 0.746 * Hp
1 kg-m² = 23.73 lb-ft² therefore:
J (kg-m²) = J (lb-ft²) / 23.73
Inertia from kW and speed in units of Kg-m² (23.73 lb-ft² = 1 kg-m²)
1800 1200 900 720
401.6
275.6 474.9
317.3 547.0
176.9 358.2 617.8
196.6 398.7 687.7
216.2 438.3 756.8
92.8 254.1 516.2 893.0
105.9 290.8 592.5 1025.
7
] - 0.0685 * [Hp / (rpm/1000)
2.4 1.5
600 514 450
533.9
657.8
565.1 780.4
508.2 738.7 1020.6 1356.9 1750.5 2204.0 2718.1
624.9 908.6 1255.8 1670.5 2157.6 2713.9 3350.2
739.6 1075.9 1487.1 1978.9 2553.7 3219.6 3973.9
852.5 1240.2 1715.5 2284.0 2945.6 3712.6 4584.9
963.8 1402.4 1940.6 2583.2 3337.5 4205.6 5191.7
1073.3 1563.0 2161.8 2878.2 3721.0 4690.3 5790.1
1182.0 1721.4 2385.2 3173.2 4100.3 5166.5 6384.3
1395.3 2033.7 2815.0 3754.7 4850.4 6114.6 7555.8
1604.3 2338.8 3240.6 4323.6 5587.9 7045.9 8710.5
]
1.8
400 360 327
709.2 914.5 1150.9 1419.7
874.4 1127.7 1419.3 1750.9
1037.1 1338.0 1683.9 2077.5
A
300
499