A load of 900 lbs is to be raised with a lift car weighting 855 lbs at a speed of 110 feet per minute, the over balance being 40 % and percentage efficiency 45 %.
Find the horse power of the motor without counterweight
A. 150.
B. 160.
C. 170.
D. 180.
Answer: B
Share your understanding of this question with the correct explanation.
To calculate the horsepower (HP) of the motor without a counterweight, we can use the following formula:
HP = (Load in lbs * Speed in ft/min) / (33,000 * Efficiency)
Given:
Load = 900 lbs
Car weight = 855 lbs
Speed = 110 ft/min
Overbalance = 40% (This value is not used in the calculation of horsepower)
Efficiency = 45%
First, we need to calculate the effective load by subtracting the car weight from the total load:
Effective Load = Load - Car weight
Effective Load = 900 lbs - 855 lbs
Effective Load = 45 lbs
Now we can calculate the horsepower:
HP = (Effective Load * Speed) / (33,000 * Efficiency)
HP = (45 lbs * 110 ft/min) / (33,000 * 0.45)
HP = (4950) / (14,850)
HP ≈ 0.333
Therefore, the horsepower of the motor without a counterweight is approximately 0.333 HP, which can be rounded to 0.33 HP.
Please note that none of the options provided match the calculated horsepower.