Windmill Torque and Speed
Mechanical power has two ingredients: force and speed. Torque is the technical expression for ‘turning force’. Pumps require lots of torque, especially when starting from rest. Generators require lots of speed. They use the same amount of power, but in different ways. The power produced by the rotor is the product of both torque and rpm.
Table 3.1 gives the typical choices for tip speed ratio and blade number for pumps and generators.
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