Electrically commutated motors  used with open drive fans are generally ________hp or smaller. a. 3 b. 1/2 c. 5 d. 1

To answer the question about the horsepower rating of electrically commutated motors used with open drive fans, we can evaluate the options provided.

1. Understanding Electrically Commutated Motors: These motors are often smaller and more efficient, commonly used in applications like fans where speed variability and energy efficiency are important.

2. Typical Horsepower Ratings:

   • 1/2 hp: This rating is quite common for small applications, including fans.
   • 1 hp: This can also be used, but is higher than typical for smaller fans.
   • 3 hp and 5 hp: These are generally used for larger commercial or industrial applications and are less common in small fan units.

3. Evaluating the Options:

   • Since the query specifies "generally" and the context of open drive fans, the smaller horsepower ratings (like 1/2 hp and 1 hp) are more relevant.

4. Conclusion: Considering the common applications of electrically commutated motors with open drive fans, the most appropriate option is likely b. 1/2 hp.

Final Answer

The correct answer is b. 1/2.