According to the national standard, starting a 15KW generator requires at least a 25KW generator.
You can choose a generator with a nominal power of 40KW (maximum power 44KW). Unit with diesel engine power of 50KW (68HP). If you have a generous budget, it is recommended to choose a 50 kW generator, so that the voltage fluctuation is lower.
It would be irresponsible to answer this question in general terms and the specific issues should be analyzed in detail.
The rated current of the 15KW, 380V generator is approximately 28A. The rated current of a 7.5 kW motor is about 14A, and the motor starting current will reach 3-7 times the rated value (40-100A), which will definitely cause the generator to shut down for protection.
Please note that the above 40-100A current is the starting current. If the 7.5 kW motor is started without load or with a clight load, the starting current may fall within the normal operating current range of the generator.
The 7.5KW motor can be started directly under the following conditions:
1. The engine is empty when starting, then loaded after starting;
>2. It is lightly loaded when starting, charge gradually after starting, such as towers, some water pumps, etc.
If the engine is equipped with a variable frequency starter, this will be another matter.