MOTOR A A 50 hp 1760 rmin 460 V 3phase 60Hz dripproof Baldor

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.

Solution

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

1

Motor shaft kW

HPx0.746

37.3

37.3

2

Motor Efficiency %

96.4

84.2

3

Motor input kW

shaft kW/eff.

38.69

44.3

4

Weekly Power Consumed, kWh

(3)x14x5

2708.5

3101

5

Yearly power consumed, kWh

(4)x52

140842

161249

6

Yearly cost of power , $

(5)x0.12

16901

19350

7

Assumed discount rate. % (i)

Assumed

12

12

8

Life of Motor, years(n)

15

15

9

Present worth of yearly cost, $

(6)xPWF

115111

131789

PWF=((1+i)ⁿ-1)/(i(1+i)ⁿ)

10

Present cost, $

3432

2232

11

Lifetime cost

(9)+(10)

118543

134022

12

Savings, $

15479

0(base)

Sl No.	Item	Formula	Motor A	Motor B	Remarks
1	Motor shaft kW	HPx0.746	37.3	37.3
2	Motor Efficiency %		96.4	84.2
3	Motor input kW	shaft kW/eff.	38.69	44.3
4	Weekly Power Consumed, kWh	(3)x14x5	2708.5	3101
5	Yearly power consumed, kWh	(4)x52	140842	161249
6	Yearly cost of power , $	(5)x0.12	16901	19350
7	Assumed discount rate. % (i)	Assumed	12	12
8	Life of Motor, years(n)		15	15
9	Present worth of yearly cost, $	(6)xPWF	115111	131789	PWF=((1+i)n-1)/(i(1+i)n)
10	Present cost, $		3432	2232
11	Lifetime cost	(9)+(10)	118543	134022
12	Savings, $		15479	0(base)