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7/28/2019 TdF 2010 Poster ET-Schuffenhauer
1/1
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