MOTOR A A 50 hp, 1760 r/min, 460 V, 3-phase, 60Hz. drip-proof Baldor Super E pre

ID: 2327498 • Letter: M

Question

MOTOR A A 50 hp, 1760 r/min, 460 V, 3-phase, 60Hz. drip-proof Baldor Super E premium energy efficient induction motor has a power factor of83% and an efficiency of 96.4%. The motor is priced at $3432.00 and runs at full-load 14 hours per day, 5 days per week MOTOR B A 50 hp, 1760 r/min, 460 V, 3-phase, 60Hz. drip-proof Reliance Standard duty induction motor has a power factor of82% and an efficiency of 84.2%. The motor is priced at $2232.00 and runs at full-load 14 hours per day, 5 days per week Assume the cost of energy is $0.12/Kwh. Calculate the TOTAL savings that would accrue to the High- efficiency motor during a 15-year period.

Explanation / Answer

For calculation please refer to the table below. It may be noted that higher effiency motor provides substantial savings.

Sl No.

Item

Formula

Motor A

Motor B

Remarks

Motor shaft kW

HPx0.746

37.3

Motor Efficiency %

96.4

84.2

Motor input kW

shaft kW/eff.

38.69

44.3

Weekly Power Consumed, kWh

(3)x14x5

2708.5

3101

Yearly power consumed, kWh

(4)x52

140842

161249

Yearly cost of power , $

(5)x0.12

16901

19350

Assumed discount rate. % (i)

Assumed

Life of Motor, years(n)

Present worth of yearly cost, $

(6)xPWF

115111

131789

PWF=((1+i)n-1)/(i(1+i)n)

Present cost, $

3432

2232

Lifetime cost

(9)+(10)

118543

134022

Savings, $

15479

0(base)