Is t a n b u l - t u r k e y
T. A. E. C.
ÇEKMECE NUCLEAR RESEARCH AND TRAINING CENTER
ÇNAEM -R- 182
AN OIL-WATER COOLED LINEAR MAGNET SYSTEM
M. SUBAŞI, G .TARCAN
P .K . 1, Hava Alanı, Istanbul, Turkey
1978
İ S T A N B U L - T U R K E Y
T. A. E. C.
ÇEKMECE NUCLEAR RESEARCH AND TRAINING CENTER
ÇNAEM-R- 182
AN OIL-WATER COOLED LINEAR MAGNET SYSTEM
M. SUBAŞI, G.TARCAN
P. K. 1r Hava Alanı, Istanbul, Turkey
1978
ACKNOWLEDGEMENT
'The authors would like to thank Mr. C. Şorakkaya for his technical assistance during the work.
A B S T R A C T
A linear dc electro magnet system is described which consists of 7 discrete pancake type coils (inner dia. 10 cm) with special oil- water cooling. The intensity of magnetic field is 170 Gauss/A and the max. field strength achieved with the available power supply (40 volts- 500 A) is 3 ki*. The axial field homogeneity over a long distance (80 cm) is better than 4% when the gap between the discrete is 4 cm.
Ö Z E T
YAĞ-SU SOĞUTMALI DOĞRUSAL BİR ELBKTR0-MIKNATIS SİSTEMİ
Burada özel yağ-su soğutmalı yedi a y m , ortası oyuk silindir biçiminde (pancake) bobinlerden oluşan doğrusal (lineer) bir DC elektro-mıknatıs sistemi tanıtılmaktadır. Manyetik alan yoğunluğu 170 Gauss/^ olup eldeki gtiç kaynağı (407 - 500A) ile erişilen en yüksek alan şiddeti 3 kGauss'tur* Bobinler arası uzaklık 4 cm alın dığında 80 cm'lik bir bölgede elde edilen eksenel elan düzgünlüğü 4#' den daha iyidir.
C O N T E N T
I Introduction ... 1
II A New Linear Magnet System ... 1
M OIL-WATER COOLED LINEAR MAGNET SYSTEM
M. Subaşı, G. Tarcan
I. INTRODUCTION
The constraints on the design of linear field systems lay within the field stability and the magnitude of the field ripple.
The latter which results from the gaps between discrete coils can be decreased by increasing the volume of each coil or more economi cally, by placing laminated iron rings under the coils^^. On the other hand, lack of the field stability is more pronounced when higher field strengths are concerned in the continuous operation of the system. In this case, the excessive temperature rise of coil windings should be avoided which would otherwise, lead to a change in the field strength or even damage the coil construction. This paper presents an alternate discrete coil linear magnet system which eliminates these difficulties.
II. A NEW LINEAR MAGNET SYSTEM
The whole system, shown in fig.l, can be considered consisting of 3 major parts: power supply, field coils and cooling system.
The power supply used was a commercial type dc welding gene rator having an output current adjustable up to 500 A at 40 volts. In order to utilize this current capacity, i.e., to have higher
field strength from the system as much as possible, coils were formed of individual winding groups connected electrically in parallel. All the coils except the outer ones in fig.l have 3 winding groups, each of which has the same resistance of 2 ohms. The outer coils have more groups to linearize the field along the axes. Additionally, all the coils were connected in parallel to reduce the load resistance presented to the power supply further.
2
Each field coil was wound with insulated electrolytic Copper wire (2,7 mm in dia.) on a spool like form constructed from Alumini um. In order to provide a means for cooling as well as the electri cal insulation between the spool and its windings, thin Plexiglass rods were attached radially and longitudinally to the walls and to the base of the spool respectively, as illustrated in fig. 2. In addition, axter every 4 layers of windings same kind of rods were placed on the last layer to have a number of cooling channels bet ween the layers. When the windings of the coils were completed, spools were closed by thin Aluminium covers leaving small openings.
In case the system is operated continuously under high cur rent (I 10 A), the heat generated in the windings is dissipated indirectly by means of thin grads transformer oil. Each field coil is filled with the oil and two plastic hoses are immersed in it for circulation. The oil in each coil is circulated individually by an oil pump through a large surface radiator placed in a cold water tank. Hence, the excessive heat is transferred to water.
Pig. 3 shows the variation of oil temperature measured by a sensitive electronic thermometer. It is seen that the oil circu lation is not needed for an operation lasting less than 35 minutes.
Consequently a reliable field stability is achieved. Finally, the
expected field ripple which was calculated by a computer and its experimental value are compared in fig. 4. However, it should be emphasized that field ripple can be smoothed o^t by placing lami nated iron rings under each coil.
REFERENCES
F
G
B
D
Fig.2_S hem atic view of the field coil
A_The spool (A l) , B_C. Insulation rods (plexiglass)
D_Coil windings,
E_ Electrical terminals.
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