Information
-
Patent Grant
-
6608421
-
Patent Number
6,608,421
-
Date Filed
Tuesday, January 29, 200222 years ago
-
Date Issued
Tuesday, August 19, 200320 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 310 269
- 310 261
- 310 264
- 310 265
- 310 194
- 310 218
-
International Classifications
-
Abstract
The invention comprises a two part rotor coil support block, wherein a spring disposed between the two block halves allows for the thermal expansion of coils wound around the assembled block.
Description
BACKGROUND AND SUMMARY OF THE INVENTION
The present invention relates to a controlled compliance rotor winding support block. More particularly the support block will allow the control and minimization of coil expansion forces exerted on the rotor forging of a turbine generator. This control is accomplished by the use of a non-conducting spring captured within a non-conducting block assembly.
Service reliability problems have been encountered with prior art support blocks. Support blocks in the prior art fit tightly between the rotor coils and the adjacent rotor steel. With this tight fit, low support block, high thermal expansion forces are transferred from the copper windings to the main shaft forging. These forces cause the main forging to bend causing increased unbalance with increased temperature. This thermal unbalance forces operators to reduce load or remove the unit from service.
The invention overcomes the problems in the prior art resulting from using rigid tight fitting blocks which cause thermal vibration problems and a continuing source of unit unavailability and economic loss. The invention solves the prior art problems by providing a robust, retrofit compliant block to the generator fleet which allows for thermal expansion while in service and thereby eliminates thermal unbalance.
In particular, a spring is used to compensate for the thermal expansion of the copper windings. The spring fits within a recess or pocket of one part of the block assembly and is held in place by the other part of the block assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a perspective view of the components of an exemplary embodiment of the inventive support block.
FIG. 2
is a frontal view of the assembled support block of FIG.
1
.
FIG. 3
is a cross sectional view along lines
3
—
3
of the assembled support block in FIG.
2
.
FIG. 4
is a cross sectional view along lines
4
—
4
of the assembled support block in FIG.
2
.
FIG. 5
is a top view of the spring of the support block of FIG.
1
.
FIG. 6
is a frontal view of the spring of the support block of FIG.
1
.
DETAILED DESCRIPTION OF THE INVENTION
The invention is an improvement in the rotor coil support blocking system used on large two and four pole rotors. A compliant block is used between the outermost copper coil and the steel shaft support structure. This block allows free expansion of the coils while minimizing the forces applied to the rotor structure. This invention is especially applicable to thermally sensitive rotors.
As shown in
FIG. 1
the present invention comprises three major components, first block half
10
, spring
20
and second block half
30
. In the preferred embodiment, first block half
10
is substantially rectangular and includes a protrusion
12
on one facing surface and an optional mounting groove
14
on an opposite facing surface. The mounting groove
14
is provided for assembly with a groove pin or rod (not shown). Second block half
30
includes a recess
32
which mates with the protrusion
12
of first block half
10
. Spring
20
is configured to fit within recess
32
of first block half
30
and to be contacted by protrusion
12
on first block half
10
.
FIG. 2
shows dashed lines indicating the profile of protrusion
12
, recess
32
, and spring
20
within. The radius of curvature at the corners of protrusion
12
, recess
32
, and spring
20
is approximately ¼ of an inch. The lower portions of the block halves
10
and
30
are tapered and the upper portions are curved.
FIG. 3
shows a cross sectional view of the three major components shown in
FIG. 2
along cross sectional lines
3
—
3
of FIG.
2
. As can be seen in
FIG. 3
, spring
20
is sandwiched between first half block
10
and second block half
30
.
FIG. 4
shows a cross sectional view of the assembled block, along cross sectional lines
4
—
4
of
FIG. 2
, with protrusion
12
of first half block
10
being set in to recess
32
of second half block
30
and with spring
20
disposed between the first and second block halves
10
,
30
. In the preferred embodiment spring
20
typically maintains a spacing between the first and second half blocks of 0.105 inches +/− 0.007 inches but when compressed the spring maintains a spacing between the two block halves of approximately 0.075 inches.
FIGS. 5 and 6
show the spring
20
in greater detail. Spring
20
is rectangular and approximately 2.36 inches by 4.00 inches with the aforementioned ¼ radius at its four corners. Spring
20
is a ripple spring having a pitch of approximately 1.18 inches between ripples. In the preferred embodiment a spring ripple is centered in the spring.
Although not shown, the windings around the spring block assembly maintain the three components in the physical arrangement described above. As the winding coils expand due to thermal effects, the spring is compressed taking up the thermal expansion of the winding coils.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
Claims
- 1. A rotor winding support block comprising:a first support block half being generally rectangular in shape and having a rectangular recess disposed in one facing surface; a spring shaped to fit within said rectangular recess of said first support block half; and a second support block half which mates with said first support block half wherein said spring is maintained in place between said first and second support block halves.
- 2. A rotor winding support block as in claim 1, said second support block half having a protrusion disposed in one facing surface which fits into said recess of said first support block half.
- 3. A rotor winding support block as in claim 1, said spring being a rectangularly shaped ripple spring.
- 4. A rotor winding support block as in claim 2, said spring being a rectangularly shaped ripple spring.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
2736829 |
Sills |
Feb 1956 |
A |
3108200 |
Baldwin |
Oct 1963 |
A |
Foreign Referenced Citations (6)
Number |
Date |
Country |
191006 |
Jul 1957 |
AT |
710116 |
Apr 1937 |
DE |
1003341 |
Feb 1957 |
DE |
1134748 |
Aug 1962 |
DE |
424120 |
May 1911 |
FR |
176629 |
Mar 1922 |
GB |