FIELD OF INVENTION:
The invention relates to superconducting motor and in particular, to a field coil
housing for high temperature superconducting (HTS) motor.
BACKGROUND OF INVENTION:
High Temperature superconducting (HTS) motor, consist of HTS field windings in the
rotor and the stator consists of air gap copper windings. The HTS motor field coils
unlike normal copper coils are cooled with low temperature Helium Gas (upto 30K).
The HTSC motors are highly efficient, compact, lighter and noise free motors. To
support the HTS windings, a housing is required to place the HTS field coils, which
allows the flow-in and flow out of the Helium gas with the provision of field leads. This
raises a requirement of a housing for a HTS motor that is helium leak tight,
mountable to the rotor sleeve and sealed from vacuum.
US20040017117A1 describes a superconducting rotor with the field coil supporting
member. In this patent, all the rotor field coils are cooled with conduction cooling
using single annular in &out pipeline at field coil supporting member for effective
cooling of field coils.
US20120274.161A1: This patent relates to the structure of the superconducting rotor
core. In this method superconducting field coils mounted on rotor core. The rotor core
made of a heavy solid member. The rotor core comprises rod like members and each
coaxially disposed in the cryogen passage for effective cooling of field coils.
US20140217850A1: In this invention the superconducting coils mounted with yoke
and bobbin with fibre connection type arrangement for avoiding conducting type heat
in leak. Inventor used this method for better cooling effect to superconducting coils
achieved with low heat in leak through conduction.
In the present invention, a different technique called housing type of arrangement for
mounting the superconducting coils is used for effective cooling of the field coils.

OBJECTS OF THE INVENTION:
An object of the present invention is to provide a suitable HTS field coil housing to
hold the field coils up to the. speed of 500 rpm.
Another object of the invention is to provide a suitable HTS field coil housing with
Helium leak tight in the order of 1x e-8 mbar. 1/sec.
Yet another object of the invention is to provide a suitable HTS field coil housing with
reduced number of joints with the provision of all requirements like Helium gas in and
out, field terminals etc.
Another object of the invention is to provide a suitable HTS field coil housing to
provide the suitable Helium gas flow path.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS;
Figure 1- Sectional view of pole coil housing assembly with HTS coil
Figure 2- Piping arrangement of the showing front and top view field coil housing
bottom part
Figure 3- Assembly of rotor sleeve with field coil housing with HTS coil
Figure 4- Front and Top views of the field coil housing top part
Figure 5- Sectional view of the field coil housing top part
Figure 6- Sealing plug front and tip views
Figure 7- Three-dimensional view of the HTS field coil housing

DETAILED DESCRIPTION OF THE INVENTION:
The coils are cooled up to 30K to achieve superconductivity and to produce flux for
operation of the motor. Helium gas at 30K temperature is used as a coolant for the
HTS field coils, to obtain superconductivity. Inorder to maintain the cryogenic
temperature at the field coils, the rotor sleeve along with the field coil housings are
surrounded by vacuum. The HTS field coil being an integral component need to be
designed to block the entry of the Helium gas into the vacuum space.
Fig 1 shows a sectional view of the pole coil housing assembly with HTS coil. The
housing assembly comprises a top part (2) and bottom part (1) made of a single raw
material without any joints- except for fitting the inlet and outlet pipes. Within the
housing the HTS coils (3) are placed. The housings is connected by means of both (4)
which is further connected to the cylindrical rotor to make a complete assembly with
rotor sleeve. A sealing plug (5) is provided for arresting any leakage from the
assembled housing where the bolt (4) is fixed to assemble the bottom part (1) and to
part (2) of the housing. The sealing plug (5) and the top part (2) of the housing is
welded by fusion welding (6) and the bottom part (1) and top part (2) and also welded
(7). The complete housing is assembled with rotor sleeve to make a complete rotor.
Fig 2 shows the frontal and top view of the field coil housing bottom part depicting the
piping arrangement. The HTS pole coil housing bottom part made of a single piece of
raw material where there is no joints except for fitting the inlet and outlet pipes. The
pipes are arranged in a predetermined alignment as shown in the figure.
A hollow space (25) within the housing is provided to place the HTS coil.
The field coil housing part includes means filed leads (21), means for Helium gas entry
(22), for Helium gas exit (23), holes for fixing the top part of housing with bolt and thin
layer of fusion welding to the top part.
The housing design blocks any sort of leakage of Helium Gas and the system can
withstand rotational speed upto 500rpm without affecting the cryogen flow.
Fig 3 shows an assembly or rotor sleeve (31) with field coil housing (32) comprising the
HTS coil (33). The figure shows how the arrangement is done wherein the rotor sleeve

(31) along with the field coil housing (32) is surrounded by vacuum to maintain the
cryogenic temperature at the field coils.
The housing can handle the helium gas pressure upto 5bar. High Temperature
Superconducting (HTS) motor consist of HTS windings in the rotor and the air gap
copper windings in the stator. This technology will lead in manufacturing of compact,
lighter and noise free motors. Motors with larger power ratings may be developed and
the superconducting generators can be made thereby light weight and higher
efficiency.

WE CLAIM:
1. A field coil housing for a high temperature superconducting (HTS) motor
comprising:
a single piece of raw material which functions as a bottom casing
comprising of means for passage of a coolant; a hollow area to accommodate
the HTS coil, and means to bring out the field leads.
a single piece of raw material which functions as a top casing comprising of
means for passage of the coolant.
wherein the top casing is fastened to the bottom casing followed by welding;
- wherein the means of passage of coolant may be pipes welded to the bottom
casing at predetermined distances.
. - weldable lip and ceiling plug at the top casing to arrest leakage from the
assembled housing.
wherein the housing is fastened to the cylindrical rotor sleeve.
2. A field coil housing for high temperature super conducting (HTS) motor as
claimed in claim 1, wherein the coolant is preferably helium gas.
3. A field coil housing for high temperature super conducting (HTS) motor as
claimed in claim 1, wherein helium gas pressure is upto 5 bar.
4. A field coil housing for high temperature super conducting (HTS) motor as
claimed in claim 1, wherein the housing ends are round in shape.