What is the size of alternator for given data?

Question

what is the size of alternator for given data?

torque is 17 Nm

speed is 375 rpm at pressure 7 bar

Answer 1

torque usually is applied to motors, not generators.

What does pressure have to do with alternator/generator size?

You need a spec on output voltage and current or watts.

.

Answer 2

If you are saying that the input torque and RPM are 17 Nm and 375 RPM, the input power would be .667 kW. You could estimate the size as comparable to a motor of the same power rating that is designed to operate at 375 RPM. Since data on such a motor is likely to be difficult to find, look at a motor that produces a 17 Nm torque at a higher RPM. The physical size of a machine is more nearly proportional to torque rather than power. At 1000 RPM, a machine that produces 17 Nm produces about 1.8 kW. Such a machine would be about 270 mm in diameter and 320 mm long excluding the shaft. That would be a rough estimate of the size of the machine that you describe. At 375 RPM, a 4 pole machine would produce only 12.5 Hz. A 16 pole machine would be required to produce 50 Hz.