Pumping Calculations - Basic Mathematics for Water and Wastewater Operators - page 214

■ Example 14.50
Problem: What would be the horsepower on a motor that is rated at 11 amperes and
440 volts?

Solution:

Volts Amperes
746 watts/hp

× 440 volts × 11 ampe res

= = 6.49 hp

746 watts/hp

■ Example 14.51
Problem: How many watts of power does a single-phase motor use if it pulls 10
amperes at 110 volts and has a power factor of 1?

Solution:

Volt s × Amperes × Power factor = 110 volts × 10 amperes × 1 = 1100 watts

■ Example 14.52
Problem: How many watts of power does a single-phase motor use if it pulls 10
amperes at 220 volts and has a power factor of 0.8?

Solution:

Volt s × Amperes × Power factor = 220 volts × 10 amperes × 0.8 = 1760 watts

■ Example 14.53
Problem: How many watts of power does a single-phase motor use if it pulls 11
amperes at 110 volts and has a power factor of 0.5?

Solution:

Volt s × Amperes × Power factor = 110 volts × 11 amperes × 0.5 = 605 watts

■ Example 14.54
Problem: How many watts of power does a three-phase motor use if it pulls 22
amperes at 440 volts and has a power factor of 0.8?

Solution:

Volt s × Amperes × Power factor × 1.732 = 440 volts × 22 amperes × 0.8 × 1.732

= 13,412.61 watts

■ Example 14.55
Problem: How many watts of power does a three-phase motor use if it pulls 42
amperes at 440 volts and has a power factor of 0.9?