Final answer:
The assertion that single-phase motors are more efficient than three-phase motors of comparable horsepower is false. Three-phase motors are generally more efficient, especially for higher power demands.
Step-by-step explanation:
The statement that single phase motors are more efficient than three phase motors of comparable horsepower is False. Three-phase motors tend to be more efficient, more durable, and more reliable than single-phase motors, particularly for higher power applications. The efficiency of electric motors is a crucial factor, as high-performance motors ensure that more of the electrical energy is converted into mechanical energy with less being lost to heat. This is significant in industrial applications where improving efficiency can lead to substantial energy savings and reduced operational costs. A 100-hp motor can sometimes achieve an efficiency of approximately 90%, while smaller motors, such as a 1-hp motor, might have an efficiency around 80%. Therefore, choosing the right motor and improving the power factor, as opposed to increasing the voltage input, is important for enhancing the motor's output without incurring excessive energy losses. Moreover, designs such as the three-blade design for fans can also contribute to higher efficiency and safety due to lower tip speed.