Note: Descriptions are shown in the official language in which they were submitted.
~1~42~
.
PATENT
MOTOR CO~TROL SYSTEM A~D COMPO~EXTS TEIEREOF
Background of the Invention
This invention relates generally to a motor control
system and it also relates generally to individual com-
5 ponents of the system. More particularly, but not by way oflimitation, the invention relates to a transformer, a uni-
tary housing, and a double interlock mechanism, all of which
are suitable for use in an apparatus for operating a three-
phase motor to drive a submersible pump. The present inven-
10 tion is also more particularly directed to a system andmethod for controlling the energization of a trangformer ' 8
secondary winding circuit to which a three-phase motor is
connected .
Submersible pumps are used, for example, in oil wells at
15 remote locations. Three-phase electric motors are typically
used to drive these pumps. Such a motor is rated for a
nominal line-to-voltage which must be provided within a spe-
cified tolerance for the motor to worX. This voltage is
typically provided from an electric utility through a trans-
20 former and motor controller to provide the suitable voltageand control to operate the motor as desired.
Transformers and motor controllers which have been used
in the past have been separate products. That is, the
transformer has had its own housing and the motor controller
25 has had its own housing. External connections between the
two are needed to have the two work together. Although
having two separate units might allow more flexibility in
choosing components for a particular application, it has the
possible shortcomings of increased price for two rather than
30 one unit and of increased costs for shipping and ware-
housing. Two separate units would also likely require more
space at the location where they are to be used. Therefore,
there is the need for a unitary power supply package wherein
a trans former and motor controller are interconnected and
35 housed in a single compact unit which can be readily
transported to remote locations and easily connected to a
source of electricity and a load, such as a three-phase
electric motor driving a submersible pump.
21~24~
-2-
To facilitate the use o such a unitary power supply
package at a remote location, it should be designed 80 that
a human operator on the ground can have access to at least
some internal parts should they need to be repaired or
5 checked in the field. Ground-level access should also be
provided so that the operator can readily select a desired
output suitable for the load to be energized and readily
control a master on/off switch of the power supply package.
Access to at lea6t high voltage components should, however,
10 be prevented by automatic interlocks which operate when the
master switch is "on . "
For safety and economy, the transformer within the power
supply package should be designed to provide all needed out-
put ar,d operating voltages, and it should also be designed
15 to shield against electrostatically and magnetically coupled
transients. Appropriate switching and fusing regardless of
the desired output should also be provided.
Such a unitary power supply package should also include
a readily transportable housing which accommodates all the
20 other needs mentioned above.
Another feature of the prior transformer and motor
controller systems is that the motor controller package
includes an air-insulated master power switch, a combined
current limiting and load sensing fuse and an electrically
;~5 operated start-stop contactor switch mechanism connected in
series. This places all these components on one side of the
transformer .
The disadvantage of the typical master power switch is
that it is expensive. It is e~pensive because it must be
30 constructed to operate safely within its air-insulated
environment. Further, the master power switch is typically
not used as a complete safety disconnect because it is not
constructed to disconnect safely when the motor is energi-
zed; rather it is used to isolate the downstream components
35 after the contactor switch mechanism has disconnected the
motor. An air-insulated power switch adequate to break the
load directly would be even more expensive.
A typical combined current limiting and load sensing
fuse used in prior motor controllers is also relatively
2~2~3
expensive; therefore, everytime a 6hort-circuit fault or
other current overload condition clears the fuse, it must
be replaced with a similarly expensive fuse. Another
disadvantage of using the fuse in the prior manner is that
5 it cannot be rated for all the transformer outputs which
might be avallable.
In view of these additional disadvantages, there is
the need for a system which incorporates a relatively
10 inexpensive, truly emergency safety master power switch
which is directly manually operable without the aid of any
tools to break a fully loaded circuit. There is also the
need for the system to utilize fusing which is relatively
inexpensive and which is fully effective to protect the
15 system upstream of a short-circuit fault regardless of a
selected transformer output.
SummarY of the InYentiQn
The present invention overcomes the above-noted and
20 other shortcomings of the prior art and meets the
aforementioned needs by providing a novel and improved
transformer. The transformer is filtered and preferably
shielded to protect against magnetically and
electrostatically coupled transients. This is achieved in
25 part by an integral tertiary winding.
According to the invention there is provided a
transformer, comprising a core; a primary winding; a
secondary winding; a tertiary winding having a first end
3 0 and a second end; a capacitor having one end connected to
said first end of said tertiary winding and having another
end; means for connecting said another end of said
capacitor to said second end of said tertiary winding; and
wherein said primary winding, said secondary winding, and
35 said tertiary winding are disposed on said core so that
said tertiary winding is radially in between said primary
and secondary windings.
_, , , , _ _ _ _ _
214~%4~
.
The invention further provides a three-phase
transformer comprising: three-phase primary winding means
for receiving a three-phase input; three-phase secondary
winding means, inductively coupled to said three-phase
primary winding means, f or providing a three-phase output
in response to a three-phase input; three-phase tertiary
winding means, disposed between said three-phase primary
winding mean6 and said three-phase secondary winding means,
for filtering electrostatically induced transients; and
capacitance means, connected to said three-phase tertiary
winding means, for providing capacitance so that
magnetically inducted transients are filtered out of said
secondary winding means by said connected three-phase
tertiary winding means and said capacitance means.
The invention still further provides a three-phase
transformer, comprising: three subassemblies connected
together, each of said subassemblies including: a wound
primary winding adapted to be connected to a respective
phase of a three-phase power source; an electrostatic
shield electrically insulated from and wound adjacent said
primary winding; a tertiary winding wound adjacent said
electrostatic shield; a secondary winding electrically
insulated from and wound adjacent said tertiary winding;
and at least two capacitors connected to said tertiary
windings of said three subassemblies.
Brief ~escri~tion gf the l~rawinqs
Fig. 1 is a schematic circllit diagram of transformer
and motor controller portions of the preferred embodiment
of the motor control system of the present invention.
Fig. lA ls a block diagram of a winding configuration
for one phase of the preferred embodiment of the
transformer within the transformer portion of the motor
control system.
` ` ~14~12~3
5
Fig. 2 is a side elevational view of the preferred
embodiment of a transportable containment means of the
motor control system.
Fig. 3 is a plan view of the transportable containment
means .
~14~2~3
--6--
FIG. 4 is an end elevational view of the transportable
containment means.
FIG. 5 is another end elevational view of the transpor-
table containment means.
FIG. 6 is an elevational view of an interior wall of the
transportable containment means, to which wall components of
a high voltage section of the motor controller portion of
the motor control system are mounted.
FIG. 7 is an enLarged partial side elevational view
showing the preferred embodiment of a double interlocking
means of the present invention in one operative position.
FIG. 7A is an end sectional view taXen along lines 7A-7A
shown in FIG. 7.
FIG. 8 is an enlarged partial side elevational view of
the preferred embodiment of the double interlocking means of
the present invention in another operative position.
FIG. 9 is an enlarged partial side elevational view
showing the double interlocking means in the position shown
in FIG. 8, but with a cover moved to an open position and
the handle of the double interlocking means locked in its
illustrated position.
FIG. 10 is an enlarged partial elevational view of the
preferred embodiment of a latch of the double interlocking
means shown in a latching position.
FIG. 11 is an enlarged partial elevational view of the
latch shown in an unlatching position.
FIG. 12 is a side view of a switch operating connector
block of the double interlocking means.
FIG. 13 is an end view of the connector block.
FIG. 14 is an opposite end view of the connector block.
FIG. 15 is another side view of the connector block.
FIG. 16 is a sectional view of the connector block taken
along 1 ine 16-16 shown in FIG . 15 .
FIG. 17 is a side view of a door latch operating mecha-
nism of the double interlocking means.
FIG. 18 i8 an end view of the door latch operating
mechanism .
FIG. 19 is an opposite end view of the door latch
operating mechanism.
2~4~2~3
--7--
FIG. 20 is another side view of the door latch operating
mechanism .
FIG. 21 is a sectional view of the door latch operating
mechanism taken along line 21-21 shown in FIG. 17.
FIG. 22 is a side view of a switch handle locking block
of the double interlock means.
FIG. 23 is an end view of the switch handle locking
b lock .
FIG. 24 is another side view of the switch handle
locking block.
FIG. 25 is a side elevational view of a retaining plate
providing a locking tab for the cover of the transportable
containment means.
FIG. 26 is an end view of the retaining plate.
FIG. 27 is another end view of the retaining plate.
Detailed Description of Preferred Embodiment
The preferred embodiment of the motor control system of
the present invention is schematically shown in FIG. 1 as
including a transformer circuit 2 and a motor controller
20 circuit comprising a high voltage section 4a and a low
voltage section 4b. These are encLosed within a transpor-
table containment apparatus represented by the dot-dash line
6.
The input of the transformer circuit 2 i3 adapted to be
25 connected to a suitable power source, such as a three-phase
electric utility power ~ource 8. The source 8 typically
provides a nominal line-to-line voltage higher than the
tolerable line-to-line voltage of a load to be energized
with the present invention. In the preferred embodiment
30 described herein the power source 8 provides a substantially
constant a.c. (alternating current) voltage from within the
range o~ about ~160 Vac to about 34500 Vac ( "substantially
constant" encompassing fluctuations from the nominal voltage
in a conventional voltage source). This is the input
35 voltage to the transformer circuit 2. The present invention
lowers this voltage and controls its application to the
load, such as a three-phase motor 10 connected to a submer-
sible pump 12. The windings of the motor 10 are connected
21~2~3
--8--
to outputs A, B, C of the high voltage section 4a of the
motor controller for the use illustrated in FIG. 1.
In a contemplated particular application, the motor
control system would be placed at the base of a typical
5 riser pole which supports the three-phase power lines of the
utility power source 8. Cables from the source 8 would be
run down the riser pole and connected to the inputs Hl, H2,
H3 of the transformer circuit 2. From the outputs A, B, C
of the high voltage section 4a, cables would be extended to
10 a vented junction box from which cables would extend to con-
nect to the motor 10.
Referring to FIG. 1, the transformer circuit 2 includes
a transformer 14. The transformer 14, which is a step-down
transformer that provides the only voltage level conversion
15 between the power source 8 and the motor in the illustrated
embodiment, includes three primary windings 16a, 16b, 16c
and three secondary windings 18a, 18b, 18c. The windings
16, 18 are conventional. The secondary windings 18 are
switchably interconnected by a suitable output selection
20 switch 20, such as one used in transformers manufactured by
Southwest Electric Company of Oklahoma City. In a par-
ticular embodiment, the switch 20 has two exterior handles
22, 24 (FIGS. 2 and 9) mounted on shafts passing through
the containment apparatus 6. Rotating the handles 22, 24
25 selects different taps from the windings 18 for providing
different outputs. The handles 22, 24 are manually operated
by a person standing on the ground ad jacent the motor
control apparatu6. The switch 20 of the preferred embodi-
ment provides a wide voltage range with all outputs being
30 full kVA rated. The secondary of the transformer 14 is
dedicated to a 6ingle load, namely the electrical submer-
sible pump motor 10 in the preferred embodiment.
The thus selected portion~ of the windings 18 are then
connected in either a delta or a wye connection by means of
35 a switch 26 which haA a handle 28 (FIGS. 2 and 9~ mounted on
a shaft of the switch 26 passing through the containment
apparatus 6. An example of a suitable switch 26 is the RTE
Components (Pewaukee, Wisconsin) 150A externally operated
Series Multiple Switch.
Z1~243
g
Transformer 14 also includes tertiary windings 30a, 30b,
30c. The primary windings 16, the secondary windings 18 and
the tertiary windings 30 are all inductively coupled within
respective groups to provide a three-phase transformer.
5 Each phase of the preferred embodiment i5 wound in the
manner depicted in FIG. lA wherein a core leg 32a supports
the secondary winding 18a, the tertiary winding 30a and the
primary winding 16a. It is an important feature of the pre-
ferred embodiment that these windings are in the con-
10 figuration shown in FIG. lA with the tertiary winding 30aradially in between the primary winding 16a and the secon-
dary winding 18a. A conventional electrostatic shield 34a
is disposed between the primary winding 16a and the tertiary
winding 30a. Whether the secondary is innermost and the
15 primary outermost as drawn in FIG. lA, or vice versa, is
immaterial; what is important is that the tertiary is
radially in between the two and that the electrostatic
shield 34 ( if used ) is radially in between the tertiary and
the primary. These same relationships for the tertiary and
20 electrostatic shield should be retained if additional
radially disposed windings are used within a winding group
on a core leg. Each of the other two phases is similarly
constructed as is apparent from E'IG. 1. The leg 32a and the
legs 32b, 32c (FIG. 2) in the preferred embodiment are part
25 of an overall iron core of a type known in the art.
~ he tertiary windings 30 provide electrostatic shielding
so that the transformer 14 is double-shielded. This is
achieved by grounding one end of each of the windings 30a,
30b, 30c as shown in FIG. 1 (alternatively, one tertiary
30 winding could be grounded and the other tertiary windings
could be connected to the grounded winding, or to both
ground and the grounded winding ) . This places these common
ends in a common ground connection with the conventional
electrostatic shield 34. Thus, both the electrostatic
35 shield 34 and the tertiary windings 30 f ilter electrostati-
cally induced transients~ therefore, they need to be
disposed between the primary and secondary windings. So
that each tertiary 30 can itself be shielded, the respective
electrostatic shield 34 needs to be between the primary and
214~24~
--10--
the tertiary. A different degree of electrostatic shielding
can be obtained by the tertiary windings 30 depending upon
the particular winding coniguration and axial length. In
generaL, these should be such that the electrostatic induc-
5 tion between the primary windings 16 and the secondary win-
dings 18 is measurably reduced. To maximize the shielding,
the axial length of each, tertiary winding should be at least
as long as the longer o~ the respective primary winding or
secondary winding. ,
The tertiary windings 30 also filter magnetically
induced transients in conjunction with capacitors 36, 38, 40
physically located within the high voltage section 4a of the
motor controller but electrically connected to the tertiary
windings 30. The capacitors 36, 38, 40 shown in FIG. 1 are
connected to the ends of the tertiary windings 30 opposite
the ends thereof connected to electrical ground. The capa-
citance preferably is such that the magnitude of transient
voltages induced into the tertiary and secondary windings by
lightning or switching spikes imposed onto the primary win-
dings is measurably reduced.
A third function of the tertiary windings 30 is to pro-
vide control power and metering voltages to the controller
section. This is illustrated in FIG. 1 by the connections
of the tertiary windings 30 to the low voltage section 4b of
the motor control circuit.
In a particular embodiment, each of the tertiary win-
dings 30 is implemented by a respective layer of a 3/16 inch
wide by 1/16 inch thick rectangular wire spirally wound on
the respective electrostatic shield 34 with 3/16 inch
spacing between turns. Within each phase of the transformer
14, each of the respective windings and the electrostatic
shield is electrically insulated by being wrapped on kraft
paper or other suitable insulating substrate known in the
art .
The transformer circuit 2 also includes a primary
winding circuit which connects the primary windings 16 to
the power source 8 when the power source is connected to the
high voltage t~rm;n~ls EIl, EI2, H3. This circuit includes a
primary switch 42 used for selectably energizing and de-
_ _ _
214~2~3
-11-
energizing the transformer 14 and the motor controller from
the power source 8. The switch of the preferred embodiment
is intended to be operated manually by a person standing on
the ground ad jacent where the motor control system is
located. This operation is direct, i.e., without the aid of
any tools, such as a hot stick. The switch 42 should be
rated at least for inte~rupting full load current. The
switch 42 is a true emergency safety disconnect switch which
can be directly operated by a person to break the current
conductive path between a connected power source and the
primary windings 16. When the switch 42 makes or completes
the current conductive path, the input a.c. voltage is
applied to the primary windings 16 so that an induced a.c.
output voltage is provided on the secondary windings 18.
This causes an output current to flow in a secondary winding
circuit connected to the secondary winding6 18 if the secon-
dary winding circuit is completed as subsequently described.
The resulting input current which flows through the primary
side of the transformer 14 is proportional to such output
current. The switch 42 is preferably one which is oil-
insulated so that it is relatively inexpensive despite being
able to break full load current. Any suitable type switch
can be used, such as a RTE Components two-position
Loadbreak/~oadmake stored energy type switch. This is a
three-phase switch with one pole per phase connected in
series between the source 8 and a respective primary winding
16 of the transformer 14. The operating mechanism of the
switch 42 includes a shaft 43 (FIG. 7A) which extends
through the containment apparatus 6. This pass-through of
the containment apparatus 6 and the others referred to
herein are made fluid-tight by suitable sealing members as
would be readily known in the art.
Connected in series with the respective section of the
switch 42 are load sensing fuses 44a, 44b, 44c and current
limiting fuses 46a, 46b, 46c. The switch 42 and the fuses
44, 46 can be in any order within the series configuration.
The fuses 44 are preferably field replaceable, such as
by being contained within draw-out mechanisms that penetrate
the side of the containment apparatus 6. Each fuse 44
214~2~3
--12--
includes a fuse carrier 48 having terminals connected in the
electrical series as represented in FIG. 1. The fuse
carrier 48 is also connected to the containment apparatus 6
so that an opening of the fuse carrier communicates outside
5 the containment apparatus 6 (FIGS. 2 and 9). A fuse member
50 is releasa~ly connected within the fuse carrier 48 and is
replaceable through the opening of the fuse carrier 48. A
particular type of fuse which can be used is the RTE
Components Bay-O-~et Fuse Assembly with the RTE Components
10 Dual Sensing Bay-O-~et Fuse ~ink.
The fuses 44 are relatively inexpensive because they
provide a lower current interrupting capacity which does not
have to withstand as high a current as the fuses 46. The
fuses 44 are capable of interrupting a fault current with a
15 magnitude limited solely by the sum of the internal impe-
dance of the power source 8 added to the impedance of the
transformer 14 with the secondary windings short-circuited.
Stated another way, the fuses 44 stop current flow within
the primary winding circuit in response to current flowing
20 therethrough exceeding a predetermined level in response to
a short-circuit fault in the secondary windings 18, the
secondary winding circuit, or a motor connected to the
3econdary winding circuit. That is, when a short-circuit
fault on the secondary side of the transformer 14 occurs,
25 the magnitude of the output current increases and the magni-
tude of the input current increases in response. When the
increase of the input current reaches a predetermined level,
the fuses 44 clear. The predetermined level corresponds to
the selected rating of the fuses 44. When the fuses clear,
30 the transformer and the secondary winding circuit are de-
energized. This protects the portion of the system upstream
of the fault ( towards the power source ) . The fuses 44 clear
before the current limiting fuses 46 eYcept when the current
exceeds the interrupting capacity of the fuses 44. Such
35 greater fault currents are cleared by the fuses 46.
The current limiting fuses 46 are disposed inside the
containment apparatus 6 so that they are not typically f ield
replaceable. The fuses 46 are for clearing the power lines
when the transformer 14 fails. More generally, the fuses 46
214~2~3
--13--
are capable of interrupting fault currents with a magnitude
limited solely by the internal impedance of the power source
8. An example of a suitable fuse 46 is the RTE ~omponents
E~SP Current-Limiting Backup Fuse.
Although not shown in the drawing, the transformer cir-
cuit can also include suitable conventional arresters to
shunt each line to ground in a conventional manner.
The motor controller components of the motor control
sections ~4a, 4b are conventional. Typically, the particular
motor controller would be specified by the user to coor-
dinate with other equipment. ~n example of a typical
controller is a Vortex brand motor controller.
Referring to FIG. 1, the high voltage section 4a inclu-
des a vacuum contactor 52 which is electrically operable to
connect or disconnect the outputs from the switch 26 to the
terminals A, B, C (and the motor 10 when connected thereto).
The outputs from the switch 26 are provided to the high
voltage section 4a through terminals Xl, X2, X3. In the
preferred embodiment the output includes a substantially
constant a.c. voltage within the range of about 460 Vac to
about 4160 Vac. There is one contactor pole per phase in
series between the secondary of the transformer 14 and the
output terminals A, B, C. The contactor 52 is an electri-
cally operated start-stop switch which turns a motor con-
nected to the terminals A, B, C on or off when the output
voltage is available at the contactor poles connected to the
selected secondary winding sections through the switches 20,
26 and the terminals Xl, X2, X3. These connected components
comprise the secondary winding circuit by which the motor 10
is connected to the secondary of the transformer 14. The
wiring, such as cables, used to connect the motor 10 to the
terminals can also be part of the secondary winding circuit.
When the contactor 52 is in a conductive state, and the
motor 10 is connected, the entire secondary circuit is
completed so that if there is output voltage it is applied
to the motor and output current flows through the secondary
winding, the secondary winding circuit and the motor (when
referellce Ls made to a voltage being applied or the like
from one point to another, this encompasses any voltage
2~243
-14-
drops across intervening circuitry). When the contactor 52
is in a non-conductive state, the motor 10 is not
energized .
The high voltage section 4a also includes three current
transformers 54a, 54b, 54c which sense current through the
respective phase output line to provide control signals to a
solid state logic controller 56 in the low voltage section
4b .
The controller 56 also receives sensing inputs, as well
as energizing electricity, from the tertiary windings 30.
The controller 56 is operated by start and h-o-a
(hand-off-automatic) switches 58, 60, respectively.
Indicator lights 62 signal operating conditions in a known
manner. A chart recorder/ammeter 64 is also included in the
low voltage section 4b, as is a convenience outlet 66.
Although the transformer 14 of the preferred embodiment
and its primary side switch 42, with or without fuses 44 or
46, in combination with a secondary-connected motor
controller are each novel, the motor controller components
of the high voltage section 4a and the low voltage section
4b of the motor control circuit are conventional. It is to
be noted, however, that housing all these components o~ both
the transformer circuit 2 and the motor controller circuit 4
within the single containment apparatus 6 is also novel.
Referring to FIGS. 2-6, the transportable containment
apparatus 6 of the preferred embodiment include~ a single,
multicompartment enclosure 68 mounted on a skid 70. The
skid 70 provides a base for supporting the housing on the
ground. The apparatus 6 can be positioned before or after
the external connection cables have been installed at the
site where the present invention is to be used.
The enclosure 68 includes a compartment 72 for receiving
the components of the transformer circuit 2 shown in FIG. 1.
These include the transformer 14 (except for the capacitors
36, 38, 40), the primary switch 42 and the fuses 44, 46. In
the pref erred embod iment these components are immersed
within a volume of liquid, such as a suitable oil known in
the art. The surface of the liquid is identified in FIG. 2
by the reference numeral 74. This surface is below the
2~ 442~3
--15--
access openings of the ~use carriers 48 of the field repla-
ceable fuses 44. The portion of each fuse carrier 48 into
which its replaceable fuse element 50 is connected is,
however, below the surface of the liquid, as are the other
5 components of the transformer circuit 2 which are within the
compartment 72.
The enclosure 68 includes a compartment 76 in which the
capacitors 36, 38, 40 and the components of the motor
control sections 4a, 4b are located. At one end of the com-
partment 76 there is a door 78. There is a door 80 located
within the interior of the compartment 76 to divide the com-
partment 76 into two chambers 82, 84. The components of the
low voltage section 4b shown in FIG. 1 are located in the
outer chamber 82 and on the door 78, and the capacitors 36,
38, 40 and the components of the high voltage section 4a
shown in FIG. 1 are located within the inner chamber 84.
The enclosure 68 includes a compartment 86 containing
the high voltage terminals Hl, H2, H3 (FIG. 1) to which the
power source 8 connects. A door 88 is connected at one end
of the compartment 86.
The compartments 72, 76, 86 are def ined by side walls
90, 92, end walls 94, 96, and the doors 78, 88. These are
also def ined by lower plate 100, upper plate6 102, 104 and
top 106.
Side walls 90, 92 are connected to the base 70 and
spaced from each other transversely across the width of the
base 70. These side walls can be continuous or defined by
individual, but interconnected, plates (6uch as by welding).
They extend perpendicularly from the base 70.
The end walls 94, 96 are connected to the base 70 and to
the side walls 90, 92 so that the first compartment 72
includes the end walls 94, 96 and the portions of the side
walls 90, 92 in between the end walls 94, 96 and so that the
compartment 76 includes the end wall 94 and portions of the
side walls 90, 92 extending beyond the end wall 94 away from
the compartment 72. Thus, in the preferred embodiment the
compartments 72, 76 are ad jacent each other with the common
intervening wall 94. The compartment 72 includes a floor
provided by the top of the base 70. The compartment 72 is
2~ ~L4243
-16--
covered at the top by the removable top 106 bolted to a
flange extending around the respective side walls and end
walls. The compartment 76 is completed by the lower plate
100 and the upper plate 102 and the door 78 e~ctending bet-
S ween the side walls 90, 92 at the end of the compartment 76
opposite the end wall 94. The door 80 within the compart-
ment 76 is disposed between the side walls 90, 92 inter-
mediate the end wall 94 and the door 78. Within the inner
chamber 84 of the compartment 76, the capacitors 36, 38, 40
and the components of the high voltage section 4a shown in
FIG. 1 are mounted on the end wall 94 as shown in FIG. 6.
The compartment 86 is def ined by the end wall 96 which
is shared in common with the compartment 72. The compart-
ment 86 is also defined by the ends of the side walls 90, 92
extending beyond the end waïl 96 away from the compartment
72. These portions of the side walls 90, 92 also extend
downward to ground level at the bottom of the base 70. The
compartment 86 is further def ined by the upper plate 104 .
The end of the compartment 86 opposite the end wall 96 is
closed by the door 88. The bottom of the compartment 86 is
left open so that underground cables, for example, can be
recelved into the compartment without passing through the
door 88.
Other features of the containment housing 6 are lifting
lugs 108, a grounding connector 110 and cooling panels 112.
The cooling panels 112 are vertical ilat plates connected to
the side wall 92. As shown in FIG. 5, associated with the
end wall 96 of the enclosure 68 above the compartment 86 is
a pressure relie valve 114 for relieving excessive pressure
from within the compartment 72. Also associated with the
end wall 96 above the compartment 86 is a f ill plug 116
through which the oil or other suitable liquid is flowed
into the compartment 72. A drain valve 118 (FIG. 4) allows
the liquid to be drained. An oil level gauge 120 and an oil
temperature gauge 122 on the side wall 90 monitor these con-
ditions of the liquid inside the compartment 72. A name
plate 123 is also mounted on the side wall 90.
Also associated with the side wall 90 is a cover 124.
The cover 124 is connected to the enclosure 68 so that the
214~2~3
--17--
cover 124 is movable between an open position (FIG. 9),
wherein the output selection switch handles 22, 24, the
delta-wye switch handle 28 and the fuse carriers 48a, 48b,
48c are accessible, and a closed position (FIGS. 2, 7 and
5 8 ), wherein these components mounted through ports in the
side wall 90 are inaccessible. In the preferred embodiment
the cover 124 is hinged to a support plate 126 welded or
otherwise suitably connected to the outside of the side wall
90 intermediate the end walls 94, 96. For a use to be
10 de8cribed further hereinbelow, the cover 124 includes a
retaining plate 128 connected along the edge of the cover
124 opposite the edge connected to the support plate 126.
In the preferred embodiment the retaining plate 128 has the
construction shown in FIGS. 25-27. This includes a tongue
portion 130 at the top of which a support shoulder 132 is
connected 80 that it extends perpendicularly outward from
the tongue portion 130. The portion 130 is bev~led, notched
or otherwise configured to provide both an end to be
retained by a retaining member (subsequently described) when
20 the cover 124 i5 to be locked in its closed position and a
space to allow passage of the tongue portion 130 past the
retaining member when the cover 124 is permitted to be
opened. A tab 134 extends from the support shoulder 132.
The tab 134 has a hole 136 for receiving a screw or bolt 137
25 or other suitable mechanism which can be adjusted inwardly
or outwardly through the hole 136 to engage a threaded nut
139 fixed to the side wall 90 for stabilizing the cover 124
in its closed position 80 that the cover 124 does not
rattle. When the cover 124 is in its closed position, the
30 retaining plate 128 is engaged by part of a double interlock
mechanism 138. The mechani6m 138 both locks the cover 124
in its closed position and locks the door 80 in its closed
position in response to the primary switch 42 within the
transformer circuit 2 being 6witched to its energizing posi-
35 tion.
The double interlock mechanism 138 generally depicted inFIG. 2 and more clearly shown in FIGS. 7-11 is connected to
the primary switch 42. When the switch 42 is manually
operated by a person on the ground ad jacent the containment
~14~2~
-18-
apparatus 6, the double interlock mechanism 138 automati-
cally mechanically interlocks or releases the cover 124 and
the door 80. Interlock occurs when the switch 42 is
switched to its energizing position, and release occurs when
the switch 42 is moved to its de-energizing position. When
the switch 42 is in its circuit energizing position, the
closed cover 124 and the closed door 80 are locked to prohi-
bit access to the fu6es 44 and voltage adiusting switches
20, 26 behind the cover 24 and the high voltage section 4a
components behind the door 80.
Referring particularly to FIGS. 10 and 11, the aouble
interlock mechanism 138 includes a latch 140 which is
movable between a position to engage the door 80 (FIG. 10)
and a position to disengage the door 80 (FIG . 11 ) . The
latch 140 is pivotally connected at one end on the inside of
the side wall 90 within the compartment 76. A pin 142 pre-
vents the latch 140 from pivoting backward over the center
of pivotation. The latch 140 engages a catch member 144
connected to the door 80 when the latch 140 i8 in its door
engaging position and the door 80 is closed as illustrated
in FIG. 10. In this position, the door 80 is held in its
closed position until the latch 140 is moved to its
disengaging position shown in FIG. 11. Disengagement can
occur in the preferred embodiment either by operation of the
double interlock mechanism 138 or by manually lifting up on
the latch 140 through a small opening (not shown) provided
in the door 80.
The double interlock mechanism 138 also includes manual
operating means for concurrently operating the primary
switch 42 and the latch 140 so that the latch 140 is in its
door-engaging position when the primary switch 42 is
operated for energizing the primary winding 16 of the trans-
former 14 and so that the latch 140 is in its door-
disengaging position when the primary switch 42 is operated
to its de-energizing position. The manual operating means
also concurrently prevents the cover 124 from being moved
from its closed po6ition to its open position when the cover
124 is in its closed position and the primary switch 42 is
in its energizing position. This operating means is
9- 2 1 44243
disposed on the exterior o~ the housing 6 in connection with
the side wall 90.
The manual operating means includes operating means for
operating the latch 140. The operating means is mounted
through the side wall 90 so that there is a portion of the
operating means inside the compartment 76 and another por-
tion of the operating means outside the housing 6. The
operating means includes a latch movement member 146 rota-
tably mounted to the side wall 90 in engagement with the
latch 140. The preferred embodiment of the latch movement
member 146 is shown in FIGS. 17-21. The member 146 shown
in these drawings includes a shaft 148 on the exterior end
of which is mounted a pulley 150. The interior end of the
shaft 148 includes a half cylindrical portion 152 acting as
a cam upon which the latch 140 rides as best illustrated in
FIGS. 10 and 11. Grooves 154, 156 on the shaft 148 carry a
sealing ring and a retaining ring for providing a fluid
tight seal where the shaft 148 passes through the side wall
90. The pulley 150 ha6 a threaded cavity 158 defined
therein for receiving a screw to retain a drive belt on the
pulley 150 as subsequently described hereinbelow.
The manual operating means also includes a handle 160
connected outside the housing 6 to the switch 42. In par-
ticular, the handle 160 is connected to the shaft 43 of the
switch 42 passing through the side wall 90. This connection
is made through a drive means for coupling the handle 160 to
the pulley 150 of the latch movement member 146 so that
operative movement of the handle 160 actuates the operating
means to operate the latch 140. The drive means includes a
connector 162 for connecting the handle 160 to the shaft 43
of the switch 42 outside the housing 6 so that the handle
160 is movable between a switch energizing position (FIG. 7)
and a switch de-energizing position (FIGS. 8 and 9). The
drive means also includes coupling means for coupling the
connector 162 and the latch movement member 146 so that the
latch movement member 146 moves synchronously with the shaft
43 of the switch 42 in response to operation of the handle
160 .
Re~erring to FIGS. 12-16, the connector 162 includes a
cylindrical body 164 having a transverse bore 166 to receive
_ _ _ , . .. .. .
-20- 2 ~ 44243
one end of the handle 160. The end of the handle is engaged
by a retaining screw or pin (not shown) received through an
axial hole 168. Communicating with the hole 168 is an axial
cavity 170 which receives the end of the switch shaft 43
protruding outside the housing 6 (FIG. 7A). Set screws
through threaded holes 172 secure the connector 162 to the
shaft 43. Another transverse threaded hole 174 receives a
threaded shaft or pin 176 (FIG. 7A) which defines a retainer
means for engaging the retaining plate 128 on the cover 124,
thereby retaining the cover 124 in its closed position when
the cover 124 is closed and the handle 160 is moved to the
position wherein the switch 42 is in its energizing position
( the position of handle 160 shown in FIG. 7) .
The coupling means of the drive means of the preferred
embodiment includes a drive belt 178 extending around and
connected to the cylindrical body 164 and the cylindrical
pulley 150 as illustrated in FIGS. 2 and 7-9. A guard 179
( FIGS . 2 and 7 ) can be mounted over the belt 178 .
The double interlock mechanism 138 further includes
means for preventing the handle 160 from being moved in
response to the cover 124 being moved from its closed pos i-
tion to its open position. As shown in FIGS. 2 and 7-9,
this includes a block 180 pivotally connected to the side
wall 90 above the connector 162. As more clearly shown in
FIGS. 22-24, the block 180 has a hole 182 defined therein.
~he block 180 is manually movable to a handle enabling posi-
tion atop the support shoulder 132 of the retaining plate
128 of the cover 124 when the cover is in its closed posi-
tion as illustrated in FIGS. 2, 7 and 8. The block 180
automatically moves by gravity to a handle disabling posi-
tion wherein the hole 182 of the block 180 receives the pin
176 in response to the handle 160 being in its switch de-
energizing position and the cover being moved to its open
position as is shown completed in FIG. 9. A hole 183 (FIGS.
22-24) defined in the block 180 receives a pivot pin 185
(FIGS. 7-9) connecting the block 180 to the side wall 90. A
pin 184 (FIGS . 7-9 ) stops backward movement of the block
180 .
In use, the motor control system of the present inven-
tion is transported to a location where it is to be con-
_ _ ~ _,
214~2~3
-21-
nected to a power source and a load, such as the power
source 8 and the motor 10 and submersible pump 12 com-
bination. Transportation to and placement at the location
are facilitated by the single containment housing 6 which
has all the electrical components located and interconnected
therein .
Once at the location, conventional power connections are
made to the high voltage terminals Hl, H2, H3 within the
compartment 86, and conventional load connections are made
to the terminals A, B, C in the high voltage section 4a con-
tained in chamber 84 of compartment 76. Access to the high
voltage power input terminals Hl, H2, H3 is through the door
88. Access to the normal operational switches 58, 60 and
indicators 62, 64 of the motor controller section 4a is easy
because these are mounted on the door 78 (FIG. 4). Access
through the door 80 to the output terminals A, B, C and the
other components within the high voltage section 4a,
however, is limited depending upon the state of the double
interlock mechanism 138.
Prior to operation, the handle 160 of the double
interlock mechanism 138 would be in, or moved to, the posi-
tion shown in FIG. 9. This allows the door 80 to be opened
so that connections can be made to the output terminals A,
B, C, and it also allows the cover 124 to be opened to per-
mit acce88 to the fuse~ 44 and the voltage adjusting switch
handles 22, 24, 28. When the cover 124 is open, the block
180 drops into the position shown in FIG. 9 to prevent the
handle 160 from being moved to the switch 42 energizing
pos ition .
Once the connections have been made and the output
voltage selected, the door 80 and the cover 124 can be
closed. To close the cover 124, the block 180 is manually
lifted and placed on the retaining shoulder 132 as
illustrated in FIG. 8. The handle 160 is now free to be
35 pivoted clockwise into its switch 42 energizing position
shown in FIG. 7. When the handle 160 is moved to this posi-
tion, the pin 176 is concurrently pivoted clockwise and the
latch 140 pivoted counterclockwise (as viewed in the
drawings) to their respective posiitions shown in FIG. 7.
2~2~3
-22-
The pin 176 then overLies the tongue portion 130 of the
retaining plate 128 on the cover 124 and the latch 140
overlies the catch member 144 on the door 80 to retain the
cover 124 and the door 80, respectively, in their closed
positions. This prevents the cover 124 and the door 80 from
being opened while the transformer circuit 2 and the motor
controller circuits 4a, 4b are energized. Even when these
circuits are energized, the low voltage section 4b is
accessible through the door 78 if needed. If access is not
needed, the door 78 can be closed and padlocked if desired.
Operation of the motor controller circuit, itself, is con-
ventional .
During operation of the transformer 14, the fuses 44
protect against damage resulting from an overload current in
the secondary circuit. An overload current can occur in the
secondary circuit, which causes an excessive input current
to flow on the primary side, because of short-circuit faults
in the secondary winding, the motor or the intervening cir-
cuitry such as the cables. Such short-circuit faults reduce
the secondary side impedance so that, with the output
voltage substantially constant, the output current
increases. Fuses 46 protect against a complete transformer
failure. If one or more of the fuses 44 opens or clears
when its current handling capacity is exceeded by the input
current, it can be replaced when the transformer 14 i5 de-
energized by the switch 42 and the cover 124 opened. The
used fuses are eYtracted from and new ones inserted into the
fuse carriers 48 in a known manner for the type of fuse
used. The fuses 46 are not field replaceable without
removing the top 106 or otherwise disassembling the enclo-
sure to gain entry into the compartment 72. When the fuses
46 or 48 clear, the input voltage is removed from the pri-
mary winding so that the transformer and the other
downstream components are de-energized.
During operation of the transformer 14, the electrosta-
tic shieLds 34 and the tertiary windings 30, being placed
between the primary and secondary windings, shield against
electrostaticaLly coupled transients. The tertiary windings
30 in combination with the capacitors 36, 38, 40 f ilter
magnetically coupled ~ransients.
2~2~3
--23--
During operation of the transformer 14, emergency shut-
down can be effected by a person directly manually moving
the handle 160 from its switch 42 energizing position (FIG.
7) to its switch 42 de-energizing position (FIG. 8). The
5 handle 160 is directly and safely accessible so that no hot
stick or other tool is needed to actuate the handle.
From the foregoing description of the apparatus shown in
FIGS. 1-27 and the operations thereof, it is apparent that
the present invention also includes the following methods.
A method of controlling the energization of a motor cir-
cuit comprises selectably energizing and de-energizing the
motor circuit from a primary winding circuit connected to a
primary winding of a transformer. The motor circuit inclu-
des a three-phase electrical submersible pump motor and an
15 electrically operated motor start-stop switch connected in a
secondary winding circuit to a secondary winding of the
transformer. The primary winding circuit includes a switch
connected between the primary winding and a power source.
The step of selectably energizing and de-energizing par-
20 ticularly includes manually operating the switch of the pri-
mary winding circuit without the aid of tools to selectably
make and break a current conductive path between the primary
winding and the power source. In response to making the
current conductive path through unassisted manual operation
25 of the switch in the primary winding circuit, a voltage
exists in the secondary winding circuit ~or energizing the
motor through the motor start-stop switch connected in the
secondary winding circuit. In response to breaking the
current conductive path through unas~isted manual operation
30 of the switch in the primary winding circuit, no voltage
exists in the secondary winding circuit for energizing the
motor through the motor start-stop switch connected in the
secondary winding circuit.
For the following defined method, reference is again
35 specifically made to a three-phase electrical submersible
pump motor. The motor is connected by electrical cables and
an electrically operated contactor of a secondary winding
circuit to a secondary winding of a transformer. The trans-
former also includes a primary winding connected by a pri-
2 4 3
--24--
mary winding circuit to a substantially constant a.c.voltage power source. A method of operating this motor
comprises applying the voltage of the power source across
the primary winding of the transformer so that a substan-
5 tially constant a.c. output voltage i5 induced across thesecondary winding and an output current flows through the
secondary winding, cables, contactor and motor in response
to the contactor in the secondary winding circuit being in a
conductive state. The method also includes conducting input
10 current through the primary winding circuit, including
through a fuse thereof connected between the power source
and the primary winding, the input current having a magni-
tude proportional to the output current. The method further
includes de-energizing the transformer and the secondary
15 winding circuit in response to a short-circuit fault in the
secondary winding or the secondary winding circuit. This is
achieved by clearing the fuse in the primary winding circuit
in response to the magnitude of the input current reaching a
predetermined level as a result of the magnitude of the out-
20 put current increasing to a level resulting from a short-
circuit fault in the secondary winding or the secondary
winding circuit.
A method of operating a three-phase motor connected by a
secondary winding circuit to a secondary winding of a trans-
25 former, comprises energizing the motor and protecting theprimary winding of the transformer from damage by an
excessive input current resulting from an e:~cessive output
current caused to flow as a result of a fault in the secon-
dary winding or the secondary winding circuit or the tor
30 reducing the secondary side impedance to a short-circuit
state and protecting any portion of the secondary winding
and the secondary winding circuit which is upstream of the
fault from the exce3sive output current. Energizing the
motor includes applying a substantially constant a.c. input
35 voltage to the primary winding of the transformer so that a
substantially constant a.c. output voltage is induced
across the secondary winding. Energizing the motor also
includes closing an electrically operated motor start-stop
switch connected in the secondary winding circuit in between
~42~3
~ -25-
the secondary winding and the motor so that the output
voltage is applied to the motor and an output current flows
through the secondary winding, the secondary winding circuit
and the motor . The output current is respons ive to the
;mre~;ln~-e of the secondary winding, the secondary winding
5 circuit and t~le motor. Energizing the motor further inclu-
des conducting an input current through the primary winding,
which input current has a magnitude responsive to the output
current. Protecting the circuits upstream of the fault
includes automatically clearing a fuse connected to the pri-
10 mary winding. This clearing occurs in response to the inputcurrent exceeding a predetermined magnitude. Upon clearing,
the input voltage is removed from the primary winding.
Thus, the present invention is well adapted to carry out
the ob jects and attain the ends and advantages mentioned
15 above as well as those inherent therein. While a preferred
embodiment of the invention has been described for the pur-
pose of this disclosure, changes in the construction and
arrangement of parts can be made by those skilled in the
art, which changes are encompassed within the spirit of this
20 invention as defined by the appended claims.
