Solutions
Development of three-mass thermal model of asynchronous traction motor
This article demonstrates the development of a three-mass thermal model of an asynchronous traction motor using REPEAT software.
The development and construction of technologically complex parts of huge industrial traction motors will be very costly and wasteful if the necessary basic design model is not available. This article demonstrates the development of a three-mass thermal model of an asynchronous traction motor using REPEAT software. The three-mass model of the engine includes a rotor, a stator winding and a stator magnetic core with a housing. The increase in the number of masses compared to single- and dual-mass models makes the model more accurate and suitable for calculations. At the same time, the amount of necessary information in the form of structural dimensions and coefficients of thermal conductivity and heat transfer increases.
1. Asynchronous motor NTA - 1200 is chosen as the simulated one.
2. The input data for the model are taken in accordance with Table 2.
3. The air velocity in the stator ventilation ducts is assumed - 26 m/s.
4. Air velocity in the rotor ventilation ducts is 25 m/s.
5. Air velocity in the air gap is 17 m/s.
6. Geometric parameters are selected according to the data or accepted.
7. Cooling air temperature is 20 ℃.
2. The input data for the model are taken in accordance with Table 2.
3. The air velocity in the stator ventilation ducts is assumed - 26 m/s.
4. Air velocity in the rotor ventilation ducts is 25 m/s.
5. Air velocity in the air gap is 17 m/s.
6. Geometric parameters are selected according to the data or accepted.
7. Cooling air temperature is 20 ℃.
| Thermal mass | Temperature, ℃ |
| Rotor | 104,6 |
| Stator winding | 116,1 |
| Stator magnetic core, housing | 108,6 |
Table 1. Simulation results
The transient process is shown in Figures 1,2,3. The peaks are due to the small mass, which is set to speed up the simulation process.
Fig. 1 – Thermal model of asynchronous traction motor
| Operation mode | Long |
| Power, kW | 1170 |
| Linear voltage l, V | 2183 |
| Phase current f, A | 375 |
| Rotation speed, rpm | 1295 |
| Current frequency, Hz | 65,4 |
| \( \cos\varphi \) | 0,861 |
| Efficiency,% | 95,8 |
| Slip,% | 1,03 |
| Torque , kNm | 8,629 |
| Traction force, kN | 51,58 |
| Torque , kNm | 8,629 |
| Active resistance of stator st, Ohm | 0,0298 |
| Stator scattering inductance, Hn | 0,001348 |
| Active resistance of rotor rt, Ohm | 0,0255 |
| Leakage inductance of rotor rt, Hn | 0,00107 |
| Engine weight, kg | 2600 |
Table 2. Main parameters of traction motor NTA-1200
SIMULATION RESULTS
Fig. 1 - Transient process of temperature setting in the stator winding
Fig. 2 - Transient process of temperature setting in the stator magnetic core, housing
Fig. 1 - Transient process of temperature setting in the stator winding
