Interconnecting means for coil windings and overload protector

An electrical connecting means and overload protector mounting means for a motor stator comprises a housing having a plurality of terminal receiving cavities therein which receive the ends of the motor winding conductors. The cavities are dimensioned to receive electrical terminals of the type which have wire-receiving slots therein such that upon movement of the terminals into the cavities, the ends of the windings are electrically and mechanically connected to the terminals. The terminals are also connected to lead wires by means of which the control circuits to the motor are interconnected to the windings. The housing has integral supporting means for an overload protector, the arrangement being such that the protector is located adjacent to the motor windings. The electrical connections to the protector are also achieved by terminals which are inserted into cavities in the housing.

BACKGROUND OF THE INVENTION 
The specific embodiment of the invention disclosed herein is particularly 
intended for a single phase induction motor however, other uses for the 
principles of the invention will be apparent from the disclosure. 
Conventional induction motors are usually provided with an overload 
protector in the form of a normally closed switch which is positioned 
against the coil windings of the motor and is connected to the motor 
circuitry in a manner such that the motor is stopped if the switch is 
opened as a result of a temperature rise in the motor windings. After the 
motor windings cool, the switch closes so that the motor can be restarted. 
In conventional induction motor manufacturing processes, the overload 
protector, which is usually in the form of a relatively small cylindrical 
body, is manually mounted on the motor windings by a technician and then 
secured in its desired position by cord lacings. The electrical 
connections to the ends of the windings are similarly secured in position 
on the stator by lacings which are applied during the manufacturing 
process. 
In my co-pending application Ser. No. 887,585, I disclose an improved 
connecting means for forming the electrical connections between the lead 
wires and the ends of the coil windings, an improvement which avoids the 
practice of lacing the electrical connections to the winding and which 
eliminates several time consuming assembly operations. The instant 
invention is directed to the achievement of a connecting and mounting 
means for forming the electrical connections to the coil windings and 
securing the protector in close proximity to the windings. 
In accordance with the principles of the invention, I provide an insulating 
housing which is adapted to be mounted on one face of the motor stator and 
into which a plurality of terminal-receiving cavities extend. The cavities 
have wire-admitting slots associated therewith so that the ends of the 
windings on the stator can be positioned in the cavities and upon 
subsequent insertion of the terminals into the cavities, electrical 
contact is established with the ends of the windings. The terminals are 
connected to the lead wires to form the connections extending to the 
control circuits for the motor. The electrical protector for the motor is 
supported in an integral supporting means on the housing which is located 
such that the protector is disposed adjacent to a portion of the coil 
winding. The electrical leads extending from the protector are also 
connected to the control circuits by terminals received in cavities in the 
housing. 
It is accordingly an improved mounting means for a thermal protector of a 
motor stator. A further object is to provide a combination mounting means 
for thermal protector and connector means for making electrical 
connections between and among the ends of the coil windings, the lead 
wires extending from the protector, and the lead wires extending from the 
stator to the control circuits for the motor. A further object is to 
provide a connecting and mounting means which will facilitate and simplify 
the manufacture of motor stators.

Referring first to FIGS. 1-3, the stator 2 of a typical split phase 
two-pole induction motor comprises a stack 4 of general circular laminae 
having an upper face 6, and a lower face 7. A plurality of spaced-apart 
teeth 8 extend inwardly towards the center of the stator and the windings 
12, 14 extend between selected adjacent teeth and beyond the upper and 
lower faces 6, 7 as shown. The main winding 10 is usually of a relatively 
coarse gage wire while the auxiliary winding 14 is of relatively finer 
gage wire as indicated in the drawing. The ends 12, 12' and 16, 16' of the 
main and auxiliary windings respectively are located adjacent to a 
threaded hole 5 in the upper surface 6 of the stator preparatory to their 
being connected to the lead wires as will be described below. 
The connections to the ends of the windings comprise a first lead means 18, 
20 consisting of two wires which are commonly connected to a terminal 
68-1, a second lead 22 which is connected to a terminal 68-2, a third lead 
24 which is connected to a terminal 68-3, and a fourth lead 28, 30 
consisting of two wires which are connected to a terminal 68-4. The lead 
24 and the portion 28 of the lead means 28, 30 extend from the cylindrical 
body 26 of thermal protector. Protectors of this type comprise a normally 
closed switch which opens in response to a temperature rise and which 
automatically closes when the temperature returns to a predetermined 
level. An additional electrical connection may be required in the form of 
a ground wire 32 which has a ring tongue terminal 34 on its end and which 
is connected to the stator by a fastener, as will also be described below. 
A housing and mounting means 36 is provided which houses the electrical 
connections required and supports the thermal protector. This housing is 
advantageously of a molded thermo-plastic material such as nylon. This 
housing is generally V-shaped and comprises divergent arms 38, 40 which 
extend from an enlarged center section 42. Each of the arms 38, 40 has a 
terminal-receiving or upper face 44, as viewed in the drawing, front and 
back sidewalls, 46, 48, endwalls 50 and a base surface 51. First, second, 
third, and fourth cavities 52, 54, 56, and 58 respectively extend into the 
upper faces 44 of the arms as shown, the first cavity being adjacent to 
the outer end of the arm 38, the second cavity being adjacent to the outer 
end of the arm 40, and third cavity 56 extending into the arm 40 adjacent 
to the center section 42, and the fourth cavity 58 extending into the arm 
38 adjacent to the center section 42. The cavities are identified in this 
irregular order in order selectively to associate the cavities with the 
wires 18, 20, 22, 24, and 28. 
Wire-admitting slots are provided in the sidewalls 46, 48 to permit 
placement of the ends of the coil windings selectively in the first, 
second, and third cavities 52, 54, and 56. The slots 60 for the cavity 52 
are of a width such that they will receive the end portion 12 of the main 
winding 10 and the slot 62 which is associated with the cavity 54 has a 
width such that it will admit the end portion 16 of the auxiliary winding 
14 but it will refuse admittance to either end 12, 12' of the main 
winding. As shown, the slots 62 are of a reduced width in their lower 
portions to achieve this selective admission of the ends 16, 16'. Two 
wire-admitting slots 64, 66 are provided in each sidewall 46, 48 in 
association with the third cavity 56. One of these slots is dimensioned to 
receive the end 12' of the main wire and the others, like the slot 62, are 
dimensioned to receive only the end portion 16' of the auxiliary winding 
14. As shown in FIG. 7, each of the cavities has a supporting boss 67 
extending upwardly from its inner end. These bosses support a wire 
positioned with its axis extending across the cavity so that upon 
insertion of a terminal, the wire will be received in the wire-receiving 
slot of the terminal as described below. 
The terminals 68-1, 68-2, 68-3 and 68-4 are identical and are of the type 
shown in FIG. 6. Each terminal is generally U-shaped having web 70 and 
parallel sidewalls 72, 74. A neck portion 76 extends upwardly from the 
sidewall 72 and has a crimpable ferrule 78 on its end by means of which it 
can be electrically and mechanically connected to a lead wire. A flange 80 
extends inwardly from the upper edge of the sidewall 74 towards the 
sidewall 72 and serves to stabilize and rigidify the sidewalls. 
Wire-receiving slot means 82, 84 extend upwardly through the web 70 and 
through the sidewalls, the wire-receiving slot 82 being of a width such 
that it will receive, and establish electrical contact with, either of the 
ends 16, 16' of the auxiliary winding while the wire-receiving slot 84 is 
dimensioned to receive either of the ends 12, 12' of the main winding. A 
central slot 83 is also provided. Slot 83 does not receive a wire but 
serves to separate the spring systems of the two wire-receiving slots. 
Electrical contact is achieved by virtue of the fact that the edges of 
these wire-receiving slots 82, 84 penetrate the insulation of the wire and 
establish electrical contact with the core thereof. 
It will be noted in FIG. 6 that each of the slots 82, 84 has shear lines or 
cut lines 79, 81 associated therewith. The shear lines 79 extend from the 
edges of the slot laterally away from the slot and the shear lines 81 
extend from the ends of the shear lines 79 parallel to the slot and 
towards the inner end of the slot. These shear lines are produced during 
manufacture of the terminal by shearing the blank along the lines 79, 81 
and bending the material bounded by these lines out of the plane of the 
blank. Thereafter, the bent out material is pushed or bent back into the 
plane of the blank. When this material is returned to the plane of the 
blank, a shoulder is formed on each edge of each slot which shoulder faces 
downwardly as viewed in FIG. 6 and towards the wire-receiving end of the 
slot. The shoulder is formed because of the fact that the irregularities 
produced in the planes of shearing prevent the material bounded by the 
shear lines from returning to its original position and it is displaced 
outwardly towards the center of the slot. The very narrow shoulders thus 
produced provide edges which cut into or penetrate the varnish-type 
insulation of the wire while the wire is moved into the slot. 
The terminals 68 can be inserted into the cavities in only one orientation 
and the wire-admitting slots 60, 62, 64, and 66 in the housing are located 
such that the appropriate wire-receiving slots, 82, or 84, will engage the 
wire which is positioned in a particular cavity. 
The cavity 58 does not have any wire-admitting slots associated therewith 
although it does receive the terminal 68-4. The terminal 68-4 serves 
primarily as a strain relief for the conductor 28 which extends from the 
protector so that any tensile forces applied to the conductor 30 will not 
be transmitted through the conductor 28 to the terminal protector. 
The central section 42 of the housing has a pair of spaced-apart columns 86 
extending upwardly from its upper surface 85 and the opposed surfaces of 
the columns are provided with arcuate depressions 88 dimensioned to 
receive therebetween the cylindrical housing of the protector 26. A recess 
90 is provided in the lower portion of the central section 42 and an 
opening extends through the floor of this recess for the accommodation of 
a screw 92. 
The housing 36 is assembled to the stator 2 after the stator has been 
dipped in a polymeric material and baked at an elevated temperature to 
cure the polymer. After the baking steps, the ends 12, 12', and 16, 16' 
and the windings will be located as shown adjacent to the threaded opening 
5 in the upper surface 6. The ring tongue terminal 34 is located in 
alignment with the threaded opening and the housing 36 is then positioned 
on the upper surface 6 and secured thereto by means of the screw 92 so 
that the electrical connection of the ground wire 32 of the stator is 
achieved. Thereafter, the end 12 of the winding 10 is positioned in the 
slot 60, the end 16 of the winding 14 is positioned in the slot 62, and 
the remaining ends 12', 16' of the windings are positioned in the 
appropriate slots 64, 66 so that they will rest upon the support bosses 67 
in the cavities. The terminals are then inserted into the cavities and the 
terminals and the lead wires are thereby connected to the appropriate ends 
of the windings. Thus, the end 12 of the main winding is connected to the 
terminal 68-1 and thereby to conductors 18, 20, the end 16 of the 
auxiliary winding is connected to the terminal 68-2 and to the conductor 
22, and the remaining ends 12', 16' are commonly connected to the terminal 
68-3 and to the lead 24 which extends from the protector. As previously 
mentioned, the terminal 68-4 serves a mechanical function rather than an 
electrical function in that it serves as a strain relief for the remaining 
lead 28 of the protector. The protector is thereafter positioned in and 
between the columns 86 and as shown in FIGS. 4 and 5, it will be 
positioned beneath a portion 94 of the auxiliary winding. In FIG. 4, the 
motor housing is shown at 96 in covering relationship to the housing 36 
and the protector. 
The circuitry for a typical split phase two-pole induction motor is shown 
in FIG. 8 and the connections among the conductors shown in FIGS. 1 and 2 
are identified. As indicated in FIG. 8, the conductors 20 and 22 extend to 
a centrifugal switch 98 which is normally closed so that power is supplied 
to both of the windings 10, 14 when the motor is started. After the motor 
attains its operating speed, the centrifugal switch 98 opens and power is 
supplied only to the main winding 10.