7/28/2019 TdF 2010 Poster ET-Schuffenhauer

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University o f Applied

Sciences Dresden

COOLING OF ELECTRIC MACHINES

BY MULTI-PHASE SYSTEMSUwe Schuffenhauer, Wojciech Urbaski, Norbert Michalke, Hans Ku

Faculty Electrical engineering

University of Applied Sciences DresdenCentre of Applied Researchand Technology (ZAFT)Friedrich-List-Platz 1,D - 01069 Dresden, Germany

XLVI MIDZYNARODOWESYMPOZJ UM

MASZYN ELEKTRYCZNYCHSME 2010

Course with increased conductivity of the PCM,

Temperatures in the simulation model similar to the ASM at rated power Temperature distribution in the model during the cooling phase

Motor with electronic dummy,visible: Cooling element

Paraffin RT80,Rubitherm

Experimental setup, to the leftinduction motor ASMmK

Motor with Paraffin-filled container,melted in the upper part

Introduction

High potential for increase the power density and the

efficiency of electrical machines consists in an improved

cooling

electrical motors belong to the most common drives in industry

the enhanced effort of renewable energy leads to an intensifiedturn for alternative drive concepts in the mobile field.

at adaptation to direct drives, the thermal decoupling is droppedoften from motor and process and the necessity exists of anintense motor cooling.

trend in the lower and middle performance range goes clearlyfor the design of the permanently excited synchronous motor

a further trend is the design of the winding as so called teethcoil technique which allows the construction of machines withshorter and bulk winding overhangs already partly poured

Motivation

Model construction

The investigations on the model of an asynchronous motor have shown that the transfer of PCM in direct contact with windings of electrical machines ispossible and can improve the loss transfer and further data of the machine. With the thermal FEM simulation models in ANSYS, the possibility could bemanaged to be able continuing investigation for further materials or structures without extensive experimental studies.For the effect of the utilization of the heat of fusion, the poor thermal conductivity of the PCM hinders a rapid breakthrough in technology. Further workshould therefore focus on materials research, and less with the aim of finding a medium with higher storage density that is suitable for the conditions ofelectrical configurations than rather to achieve better utilization of the available volume by better thermal conductivity.

The selection, arrangement and the amount of PCM material must be matched to the engine and the respective loading, just as the melting point withthe limit temperature of the windings. One possible application of the principle is given in the equipment of a motor with the new cooling system insteadof buying a more powerful drive.

Conclusions

Asynchronous machine ASMmK with Paraffin in simulation

Temperature distribution in the model of the ASMmK with new cooling system

Convection

Thermal conductivity

Gliwice - Ustro21-24 czerwca 2010 r.

Warsaw University of TechnologyFaculty Electrical engineeringPl. Politechniki 1,00-661 Warszawa, Poland

20

40

60

80

100

120

140

0 1000 2000 3000 4000 5000 6000

Time in s

TemperatureinC

Mpkt1

Mpkt2

Mpkt3

Mpkt4

Mpkt5

Mpkt6

Mpkt7

Mpkt9

Air gap

20

40

60

80

100

120

140

0 1000 2000 3000 4000 5000 6000

Time in s

TemperatureinC

Mpkt1

Mpkt2

Mpkt3

Mpkt4

Mpkt5

Mpkt6

Mpkt7

Mpkt9

Air gap

130,1

142,3134,8

124,8120,4 122,2

115,5

105,2

0

20

40

60

80

100

120

140

160

FinaltemperatureinC

ASM without Paraffin ASMmK with Paraffin

Mpkt.1:

windinghead,above,outside,

DS

Mpkt.2:

slotopening,atwinding,

DS

Mp

kt.5:

windinghead,above,

inside,

DS

Mpkt.10:

wind.

head,

down,outside,

DS

0

50

100

150

200

250

300

350400

450

0 20 40 60 80 100 120

Temperatur in C

StoragedheatbyvolumeinkJ

/l Water

RT80, with PT

GR80, with PT

Iron

Aluminium

AcknowledgementThe authors thank the German ResearchFoundation DFG for their support of theproject Influence of an integrated threshingdrive to the coring and separationprocesses on a threshing cylinder. Theproject is worked together by the Universityof Technology Warsaw and the Universityof Applied Sciences Dresden.

Thermal simulation and perspectives

New Solution Approach

the pouring of the electric components into a medium, whichguarantees a better heat emission to the housing in a combinedmanner with a new cooling concept by utilization of change itsphase

that maximum loads could be absorbed thermally

conflation of electrical motor and electronics as further aspect

due to the spatial integration in a single cooling system, thereare new solutions by taking advantage of innovative coolingconcepts such as the use of changes in the aggregate state,which are apt to combine the use of different thermal timeconstants of motor and electronics

investigation at a realistic experimental model on the basis ofa 3 kW induction motor ASM

)( 21 TTAd

Q

)( 21 TTAQ

TcmQ m

Phase Change Materials

KmW //200

)( 42411 TTAQ

mqQS

Heat storage

Latent heat

Radiation

PCM products for electro techniques

Paraffin, melting temperature up to 150 C, noseparation, cycle stable, chemically inert and nottoxic, do not cause corrosion of metals

Salt hydrates (example: sodium acetate trihydrateNaCH3COO3H2O), disadvantage tendency toseparation during melting

eutectic mixtures of salt hydrates (example:magnesium nitrate hexahydrate Mg(NO3)26H2O), nophase separation, high cycle stability, multi-component, higher rate of melting temperatures, highpotential particularly on melting enthalpy

sugar alcohols (examples: erythriol, mannitol),organic in nature, no separation, no chemicalcorrosion of metals, melting points in the range ofelectrical components

Stored amount of heat for RT80 and GR80 withphase transition (PT) compared to other materialswithout PT, by volume

Comparison final warming of the ASM andASMmK with new cooling system

Survey of selected PCM materials

Cooling concept

Comparison between measurements and simulation

by 3D modelling in ANSYS stationary and transient thermalanalysis to determine the temperature and heat flux density ispossible in the entire simulation model

for comparison with the experiments temperature samples wereplaced at the points of measurement points

the simulation results coincide with the measurements on themodel motor, also at the transient course and with paraffin

the model also allows simulation of the transient calculations withnew PCM or encapsulated and composite materials, the meltingbehaviour of the PCM and the simulation of cyclic load

it was found as in the experimental studies the problem of heatdistribution due to the poor thermal conductivity of the paraffin

Measurement results

0

100

200

300

400

500

600

700

-50 0 50 100 150 200

Melting point in C

MeltingheatbyvolumeinkJ/l

Water

Paraffin

Paraffin C30

Natrium

Erythriol

D-Mannitol

Galactikol

Mg(NO3)2 6H2OBa(OH)2 8H2ONaCH3COO3H2O

Requirements for PCM vary depending on

the application

in other technical fields such as the architecturaland medical technology utilization of both thesensitive and the latent heat storage is commontechnologically-industrially

essential requirements for PCM are of physical(proper temperature of the phase transition, highmelting enthalpy, heat capacity, thermalconductivity; reproducible phase transition, lowundercooling), technical (low vapour pressure,volume change, corrosiveness; chemical andphysical stability) and market type (low price,toxicological safety, handling / processing).

Physical basis