What factor does the rotor body depends upon in the construction of hydro-generators?

The construction of hydro-generators, specifically the design of the rotor body, depends on several key factors:

1. Design Speed and Type of Hydro-turbine: The speed at which the rotor will operate is largely determined by the type of hydro-turbine (e.g., Francis, Pelton, or Kaplan) driving the generator and the head of water available. The diameter and length of the rotor are influenced by the desired speed of operation, as the rotor must be designed to safely withstand the mechanical stresses of rotation at that speed.

2. Power Output Requirements: The electrical power output required from the hydro-generator directly influences the size and construction of the rotor. Higher power outputs require larger generators with bigger rotors that can generate more magnetic flux.

3. Electrical Frequency: The desired electrical frequency (typically 50 or 60 Hz) influences the rotor’s design, especially its speed of rotation. The number of poles on the rotor is chosen based on the generator’s rotational speed and the required electrical frequency, according to the formula (f = frac{P times N}{120}), where (f) is the frequency in Hz, (P) is the number of poles, and (N) is the rotational speed in RPM (revolutions per minute).

4. Cooling Requirements: High-power hydro-generators produce significant amounts of heat, and the rotor design must accommodate sufficient cooling to prevent overheating. This can be achieved through various means,