Electrical resistors – With mounting or supporting means – Extending between supports
Reexamination Certificate
2001-08-02
2003-11-25
Easthom, Karl D. (Department: 2832)
Electrical resistors
With mounting or supporting means
Extending between supports
C338S320000, C338S215000
Reexamination Certificate
active
06653928
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a dry load test apparatus used in an electric load test of, for example, AC generator, other power supplies and the like.
2. Description of the Related Art
<Necessity for Load Test of Private Generator>
Recently, in facilities (buildings) requiring power such as factories, department stores, computer center buildings, medical facilities and a commercial buildings, it is desirable that stable power supplying can be achieved even in a power failure. For this reason, for the facilities that requires such power, a private generator such as a three phase AC generator is provided, and in a power failure, the private generator is driven urgently to supply power into the facilities so that stable power supplying has been performed even in a power failure.
Such a private generator is not always operated but limited to use only in an urgent power failure so that it is required to operate certainly in such cases. For this reason, it is required to perform the load tests periodically in order that the private generator can be operated normally in an urgent power failure.
The best method for load tests for the private generator is practical operating to generate power and supply the above mentioned generated power to apparatuses practically using power (electric apparatuses, such as an interior illumination and a cooler) in factories or department stores. But, if load test takes long time and there are tens of times of ON/OFF power supply tests implemented and sudden rising up test of power capacity, it is difficult to perform the load test by using an apparatus requiring practically power (for example, electric apparatus such as an interior illumination and a cooler), and the apparatus is not appropriate for the test.
Therefore, practically, the load test for private generator has been performed using a load test resistor comprising a load resistor having capacity apt to the capacity of generator.
<Conventional Example of a Load Test Apparatus>
Further, a three phase AC generator has been used in the above mentioned private generator. Hence, in the dry load test apparatus disclosed in Japanese Patent Laid Open No. Hei 6-34725 publication or Japanese Patent Laid Open No. Hei 7-43436 publication, three fixed resistor units which are star connected are used to obtain the load corresponding R-phase, S-phase and T-phase of the three phase AC generator.
Besides, each of the fixed resistor units has a resistor assembly comprising a plurality of bar shaped resistor elements, and load capacity is set with combination of the plurality of resistor elements.
Moreover, besides the apparatuses disclosed in the publications, there are apparatuses that switching settings of load capacity for load test can be available. For example, those are disclosed in Japanese Patent Laid Open No. Hei 9-15307 publication, Japanese Patent Laid Open No. Hei 9-15308 publication, Japanese Patent Laid Open No. Hei 9-15309 publication and the like. In the apparatuses disclosed in the publications, a large number of resistor assemblies consisting of a plurality of bar shaped resistor elements are prepared, and the large number of resistor assemblies are disposed in the upper and lower with multi stages so that a load resistor circuit is formed from the large number of resistor assemblies. Further, by the switching combination of the multi stage resistor assemblies, resistance value of the load resistor circuit can be changed.
Further, a load test resistor apparatus to which switching selection means for selecting the above mentioned resistance value of the load resistor for load test is provided is disclosed, for example, in Japanese Patent Laid Open No. 2000-19231 (P2000-19231A) publication. < >
<Load Test Apparatus for a Movable Type Three Phase AC Generator>
However, in the resistor apparatuses for load test of the three phase AC generator, there are a permanent type one which is permanently established is such as factories, department stores, pumping facilities, hospitals and the like and movable type one which is mounted on a vehicle and is carried to use in the facilities which needs the load test only when the load resistor test performs. For example, the movable type load test apparatus is that a dry load test apparatus
3
is mounted on a carrier
2
of a truck
1
, as shown in
FIG. 50A
(refer to Japanese Patent Laid Open No. Hei 9-15307 publication).
The dry load test apparatus
3
has the frame
4
attached to the carrier
2
, and R-phase, S-phase and T-phase resistor units
5
,
6
and
7
adjacently attached to the frame
4
. Each of the resistor units
5
,
6
and
7
has the same configuration.
Each of the resistor units
5
,
6
and
7
has a base frame
10
disposed on the frame
4
, a vibration isolation rubber
11
interposed between the frame
4
and the base frame
10
, and fixing nuts
13
and
14
which are screwed to the frame
4
, the base frame
10
, the vibration isolation rubber
11
and a fixing bolt
12
, and both ends of the fixing bolt
12
, as shown in FIG.
50
B.
Further, each of the resistor units
5
,
6
and
7
comprises an electric fan
15
disposed below the base frame
10
and the frame
4
and attached to the frame
4
, the isolator (isolation member)
16
fixed on the base frame
10
, the housing
17
fixed to the isolator
16
and opened at the upper and lower ends thereof, and the hood
18
which guides cooling wind from the electric fan
15
to the housing
17
. As shown in
FIG. 51
, the housing
17
has a structure that side face openings of the frame
18
having a hexagonal shape formed with angles are closed with isolation plates
19
a
,
19
b
,
19
c
and
19
d.
Also, each of the resistor units
5
,
6
and
7
has the resistor bodies
20
R,
20
S and
20
T disposed in the housing
17
. The resistor bodies
20
R,
20
S and
20
T have the resistor assemblies Ri, Si and Ti [i=1, 2, 3 cn] disposed in the upper and lower with multi stages. As shown in
FIG. 51
, the resistor assemblies Ri, Si and Ti have a plurality of bar shaped resistor elements (heaters)
21
which are provided side by side on the plane and the both ends thereof are held on the isolation plate, and an electrically conductive connection piece
22
to which the plurality of resistor elements
21
are serially connected.
Besides, as shown in
FIGS. 52 and 53
, the resistor assemblies Ri, Si and Ti of the resistor units
5
,
6
and
7
are connected to a main vacuum circuit breaker (main VCB) MB which is a high voltage switch through separate vacuum circuit breakers (separate VCB) Bi [i=1, 2, 3 cn] which are high voltage switches.
In such a manner, the multi stage resistor assemblies Ri, Si and Ti can be turned ON/OFF with the separate vacuum circuit breakers (separate VCB) Bi so that fine load introducing test of three phase AC generator can be performed.
That is, in such a configuration, the sequence for performing the load resistor introducing test of the three phase AC generator
23
are as follows.
First, the operation of the three phase AC generator
23
is started, and then, the main vacuum circuit breaker MB is operated to be ON. Next, some of numerous separate vacuum circuit breakers (separate VCB) Bi are operated to be ON. In this case, for example, a few of the large number of separate vacuum circuit breakers (separate VCB) Bi are operated to be ON by every 10 minutes, thereby the load for the power generation capacity of the three phase AC generator
23
being 25% for the first 10 minutes, 50% for next 10 minutes, 75% for next 10 minutes, and 100% for the final 10 minutes. By such a predetermined time interval, the data from the load test of the three phase AC generator
23
are taken with changing the ratio of the load for the power generation capacity of the three phase AC generator
23
changed, thereby the fine load introducing test of the three phase AC generator being performed.
However, since the high price vacuum circuit breakers (VCB) Bi are pro
Jacobson & Holman PLLC
Tatsumi Corporation
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