Document DGxjkvZ7arnNGp5jx18obv4Nn

Interoffice Communication To G. L. Foshee From P. D. Despres Date November 16, 1981 Subject High Efficiency Motors in the VCM Plant In a communication on December 4, 1980 to F. C. Haub of CED, C. D. Spangler of PED indicated that existing electric motors in the plant may be economically replaced by high efficiency motors. An investigation of the VCM Plant motors and projected energy savings indicates that no motor replacements can be economically justified. However, original specification of a high efficiency type motor should be made in aii~new applications. The high efficiency motor has an advantage over standard motors at all loading conditions, but the advantage is greatest at full load conditions. The differences in full-load efficiencies can be seen from the attached Figure 1, approximately 3% for motors 50 hp or less and 2% for larger motors. The charted values represent the mean nominal efficiencies of several motor manufacturers. The savings realized from replacement of an existing standard motor with a high efficiency model depends directly on operating load and cost of electricity. However, the VCM Plant does not pay enough for electricity to justify replacing an existing motor with a high efficiency model. The amount of money saved on a single, new continuous duty installation can be determined from Figure 2. As of September, .the cumulative 1981 cost of electricity to the plant was 3.14< per kilowatt-hour. If the average motor cost is considered, electricity prices will have to-reach the levels listed in Table 1 before any existing motor should be replaced. These minimum limits on electricity costs reflect the replacement of just one motor. However, for virtually all single continuous duty applications in the VCM Plant, two motors are required. Accordingly, purchasing two motors for one application further reduces the attractiveness of replacing existing motors. In creating Figures 1 and 2, efficiency and cost data for each size motor were averaged over three separate manufacturers. (Manufacturers commonly used in the VCM Plant and offering high efficiency models were used: Reliance, General Electric and Westinghouse.) Nominal efficiencies were used instead of guaranteed minimum efficiencies because they appear to be more appropriate, alhtough less conservative. No allowances were made for discounts on list price that may be received from each manufacturer. , The design of the high efficiency motor poses no significant maintenance problems. The principle of the motor is based on a larger number of windings on a longer aluminum stator. Rewinding of the motor can be done in Lake Charles with standard materials, retaining the design performance. The <r*\, gZst*. ^2 aluminum stator is coated with an epoxy resion to prevent corrosion in acidic environments. Although the motor is slightly heavier and larger than the standard models, frame types are interchangeable and there should be no application problems. If there are any questions or comments, please direct them to me (ext. 5049) rqu I u dpi Cw Process Engineer br cc i JAD-JWW-JRH-MLA-CRH-DLD-PE CCR 0000X8526 Figure. i. Coupes150 k of tpb ave^^e anu CCR 000018527 o % DcF Rate of Return O T4&LS +!p MtfijiMLLM LetT&tctTY Cgsts To J~USTip-y f?PcACi*JcS) A 'STA/srp#K2> HOTCE Wrm A f4i<St^i ff/c/&aJc?/ Mert>sL.. Morrow (Lost? 4 Eu=cT&c/Ty Fox A IXLF gSTUKfiJ OF* /s% 30% s* 4/0 SZO IO (eZO 7.3 ^? 5T.S /3.0 10.2. 10.3 ts~ 820 zo 1,010 25" 1,2.40 <*. 6.3 t.3 ` ll.(o U-3 n. 2 30 l,SlO S.f /c. 2 40 1,780 5"0 Z,37C to 3000 87 n.z *9.3 IS. S' 17.7 !(,.{, 7* too IZ 3,?IO ' 4$(qO (o,IOO 9.3 n.f II.6 Ifo.b 20.9 Zl.l ISO ZOO (o?eo 8.8 SO tz.f It-7 zz. 7 2d).s . TM* &a*is ts < ''adue. e*er &U EFM '~0`+*jes "fame s&pasett r*f&**-ij-fbcTZi*ers. /V* ^isoeru^SSj Id&cr- cy- turK- tufe k*r'e oc*sid*r+d, Z ttefrtg A* m&h. **ti*Mtc. C.h&t-*' rvr- 2>C/r &, 4i*rcjfd -4 fe.'turnej asld ihc 9S3CC.ia't0 *SSU***ipi<jpy<.3 {F'JiU.r< 3) CCR 0000X8530 /jJiim DeBernardi (conoco) Date n U<5^te /&" itfr&lJLsk *>\ C&e, ^x- 7hfc\ ^ fy*? yi^ZC^ ^ n$2> s7*C^eZ+ CCR 000018531