If voltage is applied across two speed terminals of a fan motor, what will happen?

When voltage is applied across two speed terminals of a fan motor, the result heavily depends on how the motor is designed. In many cases, improperly applying voltage to speed terminals, especially if done incorrectly or in a way that the motor is not designed to handle, can lead to a short circuit. This can happen if the electrical connections cause a direct bypass of the motor's controls, resulting in excessive current that cannot be safely managed.

For fan motors, particularly those that utilize different winding configurations for varying speeds, connecting the voltage to incorrect terminals may bypass the intended operational controls, leading to a fault condition. This can cause the motor to short out if the overload protection or circuit protection features do not interrupt the current flow in time.

In cases where high voltage is accidentally applied, components within the motor or circuit can fail, leading to a short. Therefore, the actual behavior observed when voltage is applied across two speed terminals can indeed signify a potential shorting condition, validating the reasoning behind this choice.