TechTopics No. 92 Heat generation estimation for ... - Siemens

www.usa.siemens.com/techtopicsTechTopics No. 92Heat generation estimation for SIMOVAC non-arc-resistant andSIMOVAC-AR arc-resistant medium-voltage controllersSiemens is often asked to provide estimated heat generationdata for our equipment. This issue of TechTopics providesinformation that allows calculation of approximate heatgenerated by the SIMOVAC non-arc-resistant andSIMOVAC-AR arc-resistant medium-voltage controllerequipment under assumed loading conditions.The heat generation data given in the table for motorcontrollers is on the basis of operation at 1.0 service factor,and assumes that each controller includes a 0.75 kVA controlpower transformer that is only lightly loaded when the motoris running. The current value for motor controllers is thecurrent typical for a machine using the fuse size shown.For transformer feeders with class E fuses installed in serieswith a class E controller, it is assumed that the continuouscurrent in amperes is in the range of 70 percent to 80percent of the E-rating of the fuse. For load-interrupterswitches (LIS) with fuses, fuse current is also assumed to bein the range of 70 percent to 80 percent of the fuse E-rating.As with motor controllers, the current used is consideredrepresentative of the current for a transformer protected bythe fuse size shown.For applications which differ from these assumptions,convert the heat generation shown for the typical currents tothat for the specific application by the ratio of the squares ofthe currents.For the main bus, the data assumes operation at full-ratedcontinuous current.To estimate the heat generated under actual loadingconditions, determine the component heat generation foreach of the components indicated in the table, withadjustments if necessary for differing currents. For simplicity,assume that main bus loading in each vertical section isequal to the total estimated load of the controller lineup, andadjust the heat generated for each vertical section by thesquare of the percentage of total estimated load to ratedmain bus current. Space heater load should be assumed tobe continuous.Answers for infrastructure and cities.

Approximate heat generation (in watts) for SIMOVAC non-arcresistantand SIMOVAC-AR arc-resistant medium-voltage controllersComponentsizeContactor 400 AFuse sizeTypical fullloadamperes(FLA) 1Full-voltagenon-reversing(FVNR)Full-voltagereversing (FVR)2R 27 A 43 W3R 40 A 57 W4R 60 A 88 W6R 83 A 118 A9R 121 A 181 W12R 151 A 228 W18R 241 A 451 W24R 343 A 692 W15E 11 A 22 W20E 14 A 24 W25E 18 A 27 W30E 21 A 30 W40E 28 A 43 W50E 35 A 46 W65E 46 A 59 W80E 56 A 70 W100E 72 A 87 W125E 88 A 104 W150E 105 A 120 W175E 130 A 167 W200E 140 A 186 W250E 180 A 254 W300E 225 A 354 W350E 263 A 448 W400E 300 A 562 W450E 348 A 659 WApproximate heat generation (in watts) for SIMOVAC non-arcresistantand SIMOVAC-AR arc-resistant medium-voltage controllersComponentsizeContactor 720 AComponentsizeLIS switch 600 ALIS switch1,200 AComponent sizeFuse size Typical FLA 1 FVNRFVR38R 490 A 758 W48X 600 A 956 W57X 689 A 1,247 W450E 348 A 503 W600E 451 A 724 W750E 520 A 956 WFuse sizeVertical section with main busCurrentFVNRFVR450E 348 A 439 W600E 451 A 586 W750E 520 A 650 W900E 630 A 1,015 WComponent sizeSpace heaters per vertical sectionRated currentVoltage transformers (VTs) (set of three, includingisolation switch)FVNRFVR1,200 A 188 W2,000 A 206 W3,000 A 250 W4,000 A 413 WConversion factor: Watts x 3.415179 = BTU/hour.FVNRFVR200 W50 WFootnote:1See text for assumptions used for typical current. For motors, typicalcurrent is that for a machine typically protected by the size of fuseshown. For transformers, current is in the range of 70 percent to 80percent of the fuse E-rating, with specific value considered typicalfor a transformer protected by the fuse size shown.2

As an example of the method of calculation, consider alineup of controllers with six vertical sections, with thecomponents shown in this table.Component Quantity Watts/component TotalVertical section with 3,000 A main bus, with total loading 2,200 A 6 220 x (2,200/3,000)2 = 108 W 648 WControllers 400 A with 12R fuses 3 228 W 684 WController 400 A with 24R fuses 1 692 W 692 WControllers 400 A with 250E fuses 2 254 W 508 WController 720 A with 57X fuses 1 1,247 W 1,247 W600 A LIS with 450E fuses 1 439 W 439 WSpace heaters 6 200 W 1,200 WVTs, one set of three 1 50 W 50 WTotal heat generation for assembly5,468 WTechTopics are published for informational purposes only. Siemensmakes no guaranty of accuracy or applicability to any specific customerprojects or applications, and assumes no responsibility for the readers’use of this information. Siemens recommends that anyone seeking touse this information in field operations consult with or verify itsapplicability through an independent qualified professional.The information provided in this document contains merely generaldescriptions or characteristics of performance which in case of actualuse do not always apply as described or which may change as a result offurther development of the products. An obligation to provide therespective characteristics shall only exist if expressly agreed in the termsof contract.Siemens Industry, Inc.7000 Siemens RoadWendell, NC 27591Subject to change without prior notice.Order No.: IC1000-F320-A179-X-4A00All rights reserved.© 2013 Siemens Industry, Inc.For more information, contact: +1 (800) 347-6659www.usa.siemens.com/techtopicsAll product designations may be trademarks or product names ofSiemens AG or supplier companies whose use by third parties for theirown purposes could violate the rights of the owners.3