Standard Motor Catalog

Section TR Technical Reference Guide

SIMPLE PAY BACK CALCULATIONS The most important factor to consider when deciding for replacement of a motor is the pay back period. A = per unit Load = (% load / 100%) B = Annual usage in terms of number of hours C = Electricity cost per kWh in $ If efficiency of the existing motor + (Eff old ) in % terms and Efficiency of the new motor = (Eff new ) in % terms. Cost difference of Motor = (Cost for Premium Eff. Motor) - (Cost for Low Eff. Motor) Where “cost for Low Eff. Motor” could be; an old running motor = 0 Or replacement for a failed motor = Cost of competitor motor Pay back (in years) = (Cost difference of motor) / (Savings) To illustrate the benefit annual savings for XSD Ultra, over competitor motor (considering minimum guaranteed efficiencies); under the following condition: Savings = Hp x 0.746 x A x B x C x

To illustrate the pay back period, to replace a 15 year old running 20 Hp 4 -pole motor with a Premium Efficiency motor, under the following operating conditions:

A = per unit load = 75% / 100% = 0.75 B = Annual usage = 7300 hours C = Electricity cost per kWh = 0.09¢

If Cost for Premium Eff. Motor = XSD Ultra ® Price = $1125.00

Refer to Table 31; to compare and note the efficiency level; from which we can arrive at:

Eff old = 88.5% Eff new = 93% Savings = $401.96

Cost difference of Motor = $1125.00 - 0 = $1125.00

Pay back in years = $1125.00 / $401.96 = 2.8 years

A pay-back period less than 3 years, is recommended for replacement.

A = per unit load = 75% / 100% = 0.75 B = annual usage = 7200 hours C = Electricity cost per kWh = 0.09¢ Hp = 20 Hp Pole = 4 Savings = 20 x 0.746 x 0.75 x 7200 x 0.09 x Annual Savings = $59.90

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TECHNICAL REFERENCE GUIDE

TR.43

Data subject to change without notice. 03/24 • www.wolongamerica.com