Background of the Invention
[0001] The field of this invention is that of electrical motors and the invention relates
more particularly to the use of current and temperature responsive motor protectors
for protecting electrical motors against overheating in certain types of refrigerator
compressor systems.
[0002] Hermetically sealed refrigerator compressor systems typically mount a refrigerator
compressor and an electrical motor for operating the compressor within a fluid-filled,
hermetically-sealed container. Lead-through pins extend through a wall of the container
in sealed, electrically insulated relation to the wall and to each other to electrically
connect the motor in an electrical circuit for operating the compressor. A motor protector
is mounted on the motor inside the container by use of a bracket or the like to be
thermally responsive to rise in temperature of the motor such as might result from
the occurrence of a fault condition in the motor. Typically, the protector is also
connected in the motor circuit in such a way that it is responsive to overcurrent
conditions in the motor such as might result from such fault conditions to also interrupt
operation of the motor for preventing overheating of the motor. The mounting of the
motor protector on the motor within the container is typically performed by the manufacturer
of the refrigerator compressor system using motor protector means furnished by another
manufacture and typically involves considerable inconvenience and expense. It can
also result in arranging the motor protector in a non uniform manner on the motor
such that the motor may provide improper protection or may cause nuisance tripping
in the system.
Brief Summary of the Invention
[0003] It is an object of this invention to provide a novel and improved hermetically sealed
refrigerator compressor system; to provide such a system utilizing a rotary type of
compressor within the hermetically-sealed container of the system; to provide such
a system which is characterized by the ease and convenience of its assembly and of
the reliability of its thermal and current response properties; and to provide a novel
and improved motor protector unit for use in such a refrigerator compressor system.
[0004] Briefly described, the novel and improved refrigerator compressor system of this
invention includes a rotary-type of refrigerator compressor. That type of compressor
and an electrical motor for operating the compressor are arranged within a fluid-filled,
hermetically-sealed container in a generally conventional manner. In that regard,
it is found that when a rotary type of refrigerator compressor is used within such
an hermetically-sealed fluid-filled container, operation of the compressor by an electrical
motor tends to produce a temperature level within the container which is substantially
uniformed throughout all parts of the container. That is, while that temperature is
subject to change, such as a rise in temperature on the occurrence of an overcurrent
or other fault condition in the system, such a temperature change tends to be rapidly
reflected in a change in said uniform temperature level throughout all parts of the
sealed system container. Therefore, in accordance with this invention, a thermal and
current-responsive motor protector means of a generally conventional type is mounted
within the system container on lead-through pins which extend through the container
wall. In that arrangement, the protector is easily and economically connected in the
motor circuit and the protector is positioned so it is promptly responsive to a selected
rise in the substantially uniformed temperature within the container for protecting
the motor against overheating. That is, the thermal response characteristics of the
motor protector are selected so it is adapted to interrupt operation of the electrical
motor in response to a selected rise in said substantially uniformed temperature which
results in a sealed system from operation of a rotary type of compressor within that
sealed container, thereby to protect the motor against overheating within the container.
Preferably the motor protector is mounted within a motor protector unit which includes
a cluster block having means for contacting the respective lead-through pins, having
leads and terminals extending from the cluster block for electrically connecting the
pins to the motor, and a motor protector element which is mounted on the cluster block
to be located in selected position in the system container when the block is mounted
on the pins. The use of such a motor protector unit further facilitates cdnvenient
and economical assembly of the refrigerator compressor system while assuring proper
thermal and current response by the protector for preventing overheating of a motor
within the system.
Brief Description of the Drawings
[0005] Other objects, advantages and details of the novel and improved refrigerator compressor
system and motor protector unit of this invention appear in the following detail description
of preferred embodiments of the invention, the detailed description referring to the
drawings in which:
Fig. 1 is a partial section view along the longitudinal axis of the refrigerator compressor
system of this invention;
Fig. 2 is a partial section view along line 2-2 of Fig. 1 illustrating the motor protector
unit of this invention;
Fig. 3 is a schematic view illustrating electrical connection of the motor protection
unit of this invention and the refrigerator compressor system of this invention.
Description of the Preferred Embodiments
[0006] Referring to the drawings 10 in Figs 1 and 3 indicates the novel and improved refrigerator
compressor system of this invention which is shown to include a refrigerator compressor
12 and an electrical motor 14 for operating the compressor which are mounted within
an hermetically-sealed container 16. A coolant fluid 18 surrounds the compressor and
motor within the container and a plurality of electrically conductive lead-through
pins 20, 22 and 24 extend through a wall 16.1 of the container in spaced, electrically-insulated
relation to the container and to each other for electrically connecting the motor
in an electrical circuit.
[0007] In accordance with this invention, the compressor 12 is of a conventional rotary
type, that type of compressor having been found to provide a temperature level within
such a fluid-filled hermetically-sealed container which is substantially uniform throughout
all parts of the container 16 during normal operation of the compressor 12 by the
motor 14 as well as during undesirable increases in that temperature such as might
result from operation of the motor during the occurrence of various fault conditions
in the compressor system. Preferably for example, the compressor 12 is of a rotary
type as described in Handbook - 1983 Equipment, Part III Chapter 12, Published by
ASHRAE 1983 and the compressor is arranged to be operated by a conventional electrical
motor disposed within the sealed container 16 in a conventional manner. Preferably
also the fluid-fill coolant 18 comprises a conventional dielectric coolant fluid such
as freon gas or the like which is maintained under pressure within the container 16
in conventional manner. Preferably also, the lead-through pins 20, 22 and 24 are embodied
in a conventional fusite cap 26 having the pins secured in openings 26.1 in the cap
in sealed, electrically-insulated relation to the cap and to each other by glass-sealing
means 28, the cap being welded to the wall 16.1 of the container in conventional manner
as indicated at 26.2.
[0008] In accordance with this invention, a novel and improved motor protector unit is mounted
within the container 16 on the inner ends of the lead-through pins 20, 22 and 24 and
is electrically connected in the electrical circuit of the motor 14 to be thermally
responsive to changes in said substantially uniform temperature level in the container
16 for protecting the motor against overheating while also facilitating easy, economical
and reliably assembly of the refrigerator compressor system.
[0009] Preferably as shown in Figs 1-3, the motor protector unit 30 comprises a cluster
block body 32 of a rigid electrical insulating material such as polycarbonate or the
like and resilent, electrical contact means 34, 36 and 38 of any conventional type
are disposed on the block for resiliently gripping and making electrical connection
to the respective lead-through pins 20, 22 and 24. In accordance with this invention,
a thermally responsive motor protector element 40 of any conventional type such as
the thermal and current-responsive protector shown in U.S. Patent 4,485,231 is mounted
on the cluster block body so the motor protector is easily connected in the electrical
circuit of the motor 14 and is disposed at a predetermined location in the container
16 to be responsive to said substantially uniform temperature in the container when
the unit 30 is mounted on the lead-through pins as described. As the protector 40
is fully described in the noted patent, it is not further described herein and it
will be understood that the protector 40 comprises any previously known motor protector
element having thermally-responsive means movable within the protector in response
to a selected rise in temperature of the thermally responsive means for opening an
electrical circuit through the protector, the protector being adapted to be connected
in a motor circuit for opening that motor circuit when the thermally responsive means
move in response to said selected rise in temperature of the thermally responsive
means.
[0010] In a preferred embodiment of the invention, the cluster block 32 is formed in two
sections 32.1 and 32.2 secured together by riveting or ultrasonic fusing or the like
at 32.3 to form a chamber 32.4. Apertures 32.5 are provided in the block sections
to fit over the respective lead-through pins 20, 22 and 24. The resilient contact
means are located inside the chamber 32.4 by locating bosses 32.6 for disposing the
contact means to resiliently grip the lead-through pins when the pins are inserted
through the block apertures 32.5 as will be understood. Preferably the contact means
each comprise resilient contact portions 34.1, 36.1, 38.1, welded to relatively rigid
contact arms or blades 34.2, 36.2, 38.2 and lead wire means 42, 44 are connected at
one end to two of the contact blades 34, 36 respectively to extend from the cluster
block. Electrical terminals 42.1, 44.1 carried at the opposite ends of those lead
wires are electrically connected to corresponding terminals on the motor 14 as shown
in Figs 1 and 3. An additional resilient spring contact portion 38.3 is welded to
an additional blade portion 38.4 of the remaining contact means and that blade portion
extends from the cluster block through an aperture 32.7 so that the contact spring
portion 38.3 resiliently grips and makes electrical connection to a terminal 40.1
of the motor protector outside the cluster block chamber 32.4. An additional lead
wire 46 is connected at one end to a second terminal 40.2 of the motor protector and
carries an additional terminal 46.1 at its opposite end connected to a corresponding
terminal on the electrical motor 14. Preferably locating bosses 32.8 provide detent
means 32.9 or the like for engaging the motor protector 40 and cooperating with the
resilient contact spring portion 38.3 for detachably mounting the motor protector
40 on the motor protector unit 30.
[0011] In that arrangement, the motor protector unit 30 is of an economical structure. It
is easily and economically mounted within the container 16 by fitting the cluster
block aperture over the pins 20, 22 and 24 for detachably mounting the cluster block
on the pins. The motor protector 40 carried on the protector unit 30 is of a conventional
type. It is easily provided with a selected actuating temperature to be thermally
responsive to a selected rise in a substantially uniform temperature level within
the container 16 to interrupt the motor circuit and prevent overheating of the motor
if such a rise in temperature should result from the occurrence of a fault condition
in the motor or the refrigerator compressor system. The motor protector unit is easily
and economically connected in the electrical circuit of the motor 14. The motor protector
40 is also easily and economically incorporated in that electrical circuit for interrupting
the motor operation in response to such a selected rise in the temperature within
the system container.
[0012] It should be understood that although particular embodiments of the refrigerator
compressor system and motor protector unit of this invention have been described by
way of illustrating the invention, this invention includes all modifications and equivalence
thereof falling within the scope of the appended claims.
1. A refrigerator compressor system having a compressor and an electrical motor for
operating the compressor arranged within an hermetically-sealed, fluid-filled container,
having a plurality of electrically conductive pin means extending through a wall of
the container in sealed relation to the wall and in spaced, electrically-insulated
relation to the wall and to each other for electrically connecting the motor in an
electrical circuit, and having motor protector means connected in the electrical motor
circuit within the container to be thermally responsive to a selected rise in temperature
for interrupting operation of the motor to prevent overheating of the motor on the
occurrence of fault conditions in the system, characterized in that the compressor
is of the rotary type the operation of which by the motor provides a temperature within
the sealed, fluid-filled container which is substantially uniform throughout all parts
of the container, and in that the motor protector means is mounted on the pin means
to be thermally responsive to rise in said substantially uniform temperature to said
selected temperature for interrupting motor operation to prevent overheating of the
motor.
2. A refrigerator compressor system as set forth in claim 1 further characterized
in that the motor protector means comprises a cluster block connector body of an electrical
insulating material, contact means mounted on the body for resiliently engaging the
pin means to resiliently grip and make electrical connection to the respective pin
means, a motor protector element mounted on the body to be Claim 2 continued thermally
responsive to rise in said substantially uniform temperature to said selected temperature
for interrupting motor operation, and lead means electrically connecting the motor
protector and the contact means to the motor for electrically connecting the motor
in said electrical circuit.
3. A motor protector unit for use in a refrigerator compressor motor system having
a compressor of the rotary type and an electrical motor for operating compressor arranged
with in an hermetically-sealed, fluid-filled container and providing a temperature
within the sealed, fluid-filled container which is substantially uniformed throughout
all parts of the container, having a plurality of electrically conductive pin means
extending through a wall of the container in sealed relation and in spaced, electrically
insulated relation to the wall and to each other for electrically connecting the motor
in an electrical circuit, and having motor protector means connected in the electrical
motor circuit within the container to be thermally responsive to a selected rise in
temperature for interrupting operation of the motor to prevent overheating of the
motor on the occurrence of fault conditions in the system, the motor protector unit
comprising a cluster block body of an electrical insulating material, contact means
mounted on the body for resiliently engaging the pin means to resiliently grip and
make electrical contact to the respective pin means for holding the motor protector
unit on the pin means, a motor protector element mounted on the cluster block body
to be thermally responsive to a selected rise in said substantially uniform temperature
within the container for interrupting motor operation to prevent overheating of the
motor, and lead means electrically connecting the motor protector and the contact
means to a motor for electrically connecting the motor in an electrical circuit.