NEMA Table
A
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
0.95
/ (rpm/1000)
2.4
] - 0.0685 * [Hp
1.5
/ (rpm/1000)
1.8
]
Hp column and converting to kW by multiplying HP * 0.746
kW = 0.746 * Hp
Then converting the equivalent inertia from Wk² to SI by dividing lb-ft² by 23.73
1 kg-m² = 23.73 lb-ft² therefore:
J (kg-m²) = J (lb-ft²) / 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
Inertia from kW and speed in units of Kg-m² (23.73 lb-ft² = 1 kg-m²)
Hp
kW
3600 1800 1200 900
720
600
514
450
400
360
327
300
100
75
533.9 709.2
914.5
1150.9 1419.7
125
93
657.8 874.4
1127.7 1419.3 1750.9
150
112
565.1
780.4
1037.1 1338.0 1683.9 2077.5
200
149
508.2
738.7
1020.6 1356.9 1750.5 2204.0 2718.1
250
187
401.6 624.9
908.6
1255.8 1670.5 2157.6 2713.9 3350.2
300
224
275.6 474.9 739.6
1075.9 1487.1 1978.9 2553.7 3219.6 3973.9
350
261
317.3 547.0 852.5
1240.2 1715.5 2284.0 2945.6 3712.6 4584.9
400
298
176.9 358.2 617.8 963.8
1402.4 1940.6 2583.2 3337.5 4205.6 5191.7
450
336
196.6 398.7 687.7 1073.3 1563.0 2161.8 2878.2 3721.0 4690.3 5790.1
500
373
216.2 438.3 756.8 1182.0 1721.4 2385.2 3173.2 4100.3 5166.5 6384.3
600
448
18.7 92.8 254.1 516.2 893.0 1395.3 2033.7 2815.0 3754.7 4850.4 6114.6 7555.8
700
522
21.2 105.9 290.8 592.5 1025.
7
1604.3 2338.8 3240.6 4323.6 5587.9 7045.9 8710.5
Control Manual
Operating Manual, A5E50491925A
499
Summary of Contents for SINAMICS PERFECT HARMONY GH180
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Page 22: ...Table of contents NXGPro Control Manual 20 Operating Manual A5E50491925A ...
Page 24: ...Security NXGPro Control Manual 22 Operating Manual A5E50491925A ...
Page 504: ...NEMA Table NXGPro Control Manual 502 Operating Manual A5E50491925A ...
Page 517: ...Index D NXGPro Control Manual Operating Manual A5E50491925A 515 ...
Page 518: ...Index NXGPro Control Manual 516 Operating Manual A5E50491925A ...
Page 530: ...Glossary NXGPro Control Manual 528 Operating Manual A5E50491925A ...
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