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Патент USA US2117123

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May'lO, 1938.
‘
'
I
c. J. WERNER
CONTROL
I
2,117,123
SYSTEM
~
Original Filed Aug. 22, 1954 I
. 54
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‘
.NVE'NTQR
551w}? Jh/erner'
BY
HIS
ATTORNEYS
Patented May 10, 1938
‘ 2,117,123
'. UNITED STATES
‘PATENT orrica
2,117,123
,_ CONTROL SYSTEM
Calvin 1. Werner, Dayton, Ohio, asslgnor to Gen
eral Motors Corporation, Detroit, Mich, a cor-,
poration of Delaware '
Original application August 22, 1934, Serial No.’
\
740,961. Divided and this application July 31,
1935, Serial No. 33,960
' 7 Claims.
(Cl. 172-279)
'
This inventions-relates to the control of electri
cal motors, and more particularly to the control
of an electrical motor in response to thermally
responsive
5
means.
'
‘
'
This application is a division of my copending
application for Control device Serial No'. 740,961,
?led August 22. 1934.
An object of this invention is to provide a con
trol system utilizing a thermal responsive switch
10 for controlling the starting and running circuits
of an electric motor, which thermal responsive
switch is so constructed and connected that the
starting characteristics of the motor are satis
factory under widely varying motor load values.
'
inclusive, of my above mentioned copending ap
pllcation, Serial No. 740,961, and is fully de
scribed in that application. This switch has a
support comprising a base indicated at ill and a
frame i2 that is secured to‘ the base. The strip of
insulating material I‘ is preferably secured to
the frame 12, and provides an‘ anchor and the
support for one end of a thermal responsive ele
ment 15, which thermal responsive element is
preferably a bimetallic‘ member having a plu
rality of longitudinal portions connected in zig
zag fashion to increase the electrical resistance
thereof. This thermal responsive element is
preferably secured to the insulating member H‘
This object is accomplished by providing a ' by rivets 18, or other suitable fastening means.
responsive to starting winding current during the
The thermal responsive element has thermals 20
and 22 at the ends thereof that are preferably‘
integral with the element. The other ends of
the thermal responsive element ii are secured
to-an insulating member ‘M by means such as
starting of the motor.
rivets 2G.
thermal-responsive switch for controlling the
starting and running circuits of the motor, which
switch has a thermal-responsive element con
nected in the circuit of the starting winding and
Inasmuch as the starting .
winding current is fairly uniform over a range
of load variations‘ normally encountered, the
switching responsive to that current will be com
25 paratively uniform over the range, and satisfac
tory starting characteristics will result.
'
Another object of this invention is to provide
a control system for an electric motor that uti
lizes a single thermal responsive element for con
30 trolling the starting and running‘ circuits of the
motor, and also provides overload protection for
the motor.
_
“
The sides of the support l2 have substantially
V-shaped notches 28 and 30 in the ends thereof.
A movable contact carrying member 32 has a.
knife edge 34 that is disposed in the notch 28 N
to provide a pivotal mounting for that contact 5
carrying member. A movable contact carrying
member 3S has a knife edge 38 that cooperates
with the notch ‘30 to provide a pivotal mounting
for the contact carrying member 36. Springs 40 30
and 42 each have an end connected to the con
tact carrying members 32 and 36 respectively,
'
This object is accomplished by providing a
thermal-responsive switch having two sets of con
' tacts, one of which sets of contacts controls the
starting and running circuits of the motor. the
other of which sets of contacts is connected to
control the power supply circuit to the motor, and
both of which sets of contacts are controlled by
and are in tension with their other ends anchored
to a suitable point. These springs tend to hold
the contact carrying member in position.
35
Contacts 44 and 46 are mounted on the con
tact carrying members 32 and .35 respectively,
and are movable therewith.
Each of these con-.
tacts is preferably positively connected to the
frame I! through leads such as 48 and 50 re- 40
'10 a single thermal-responsive element.
Further objects andadvantages of the present
invention will be apparent from the following de
scription, reference being had to the accompany
spectively. Cooperating stationary contacts 52'
and SI are secured to brackets 56 and 88 respec
Fig. 1 is a circuit diagram showing a preferred
tively, which contacts are respectively in align
_ment for engagement with contacts N‘ and 46.
A link 60 has projecting tips 82 that-extend
through holes in the insulating strip 24, and are
bent to secure the link to the insulating strip.
embodiment of the present invention adapted to
The link 60 is notched so that it has a shoulder
the control of an electric motor.
64 that engages the contact carrying member I!
Figs. 2 and 3 are modi?ed forms of the present
invention also adapted to the control of an elec—
to effect movement of the contact carrying mem- 50
her in one direction in response to ?exin'e of the
ing drawing wherein a preferred embodiment of
4 an the present invention is clearly shown.
In the drawing:
tric motor.
'
a
-
>
With particular reference to Fig. 1, the thermal
responsive switch shown is a diagrammatic rep
65 resentation of the switch shown in Figs. 9 to 14
thermal responsive‘ element IS. The link ‘I is
also notched so that it has shoulders 68 and Cl
that engage the contact carrying member I‘ to
effect movement of the contact carrying member
2,117,128
in either direction In response to ?exure of the _- thermal responsive element I68 that is part of
a thermal responsive switch I10. The heater
thermal responsive element I6. A heater ele
ment 10, that preferably comprises a resistance, element I 66ymay be either a separate resistance
unit or the inherent resistance of the thermal re
is closely associated with one surface of the ther
sponsive element itself. One end‘of the thermal
mal responsive element.
,
responsive element I68 is anchored at I12, and
The terminal 22 of the thermal responsive ele
ment is connected to ‘one end of an auxiliary or
starting ?eld winding 12 of a motor 14, which
motor also has a main ?eld winding 16 and a
rotor 18 that is preferably of the squirrel cage
type.
The other end of the starting or auxiliary .
the other end actuates a contact I14 that is in
alignrnent for engagement with a stationary con
tact I16. The stationary contact‘ I16 is con
nected to another power supply line wire I18.
The thermal responsive switches shown in Figs. .
end of the
supply line
?eld wind
heater ele
heater ele
the switch,
48 and 50
2 and 3 are preferably similar to those shown in
Figs. 1 to 4_or 6 and 7 of my previously men—'
with the movable contact carrying members 32
some such abnormal condition that might be
harmful to the motor. The circuit illustrates
the application of the present invention to a
split phase type of alternating current motor; ,
although it is understood that a similar control
?eld winding 12 is connected to one
main ?eld winding 16 and to a power
wire 80. The other end of the main
15 ing 16 is connected to one end of_ the
ment 10; while the other end of the
ment is ‘connected to the frame I2 oi
and thence through the conductors
20 and 36.
The other end 20 of the thermal re
sponsive element is connected to the stationary
contact 52, and the other power supply line wire
62 is connected to the other stationary contact 54.
With particular reference to Fig. 2, a power
tioned copending application Serial No. 740,961.
In the circuit shown in Fig. 1, the starting and
running circuits of a single phase motor are con
trolled by a thermal responsive switch. The same >'
switch also protects the motor from overload, or
circuit and control apparatus might be applied
25 supply line wire 90 is connected to one end of
a starting or auxiliary ?eld winding 92 and to one
end of a main ?eld winding 94 of a motor 96
having a rotor 88 that is preferably of the squirrel
to other types of motors or apparatus without
departing from the spirit of the invention.
cage type. The other end of the auxiliary ?eld
the thermal responsive element to directly effect
Inthe operation of the circuit shown in Fig. 1,
the auxiliary field winding current flows through -
30 winding is connected to a _stationary contact I00 ‘ heating of the thermal responsive element; while 80
of a thermal’responsive element I02; while the the‘main ?eld winding current flows through the
heater element 10 that is closely associated with
other end of'the main ?eld winding 94 is con
nected to one end of a thermal responsive ele
the thermal responsive element so that the heat
ment I04 that has one end anchored at I06 and ing of the heater element also heats the thermal
35 has a contact I08 actuated by the other end in responsive element. When the motor is not run_
alignment for engagement with the contact I00. ning the switch contacts are normally in the po
A heater element I I0 has one end connected to sition illustrated in Fig. 1. When a source of
the thermal responsive element I04, and its other current is ‘connected to the motor through the
end connected to a heater element I I2 of a switch power line wires 80 and 82, the circuits are closed
to both the main and the auxiliary ?eld windings. 40
I I4, either of which heater elements may be sepa
rate heater units or the inherent resistance of However, as the rotor speed increases in the
the thermal responsive elements themselves.
startinglv of the motor, the.» thermal responsive
The other end of the heater element H2 is con~ - element is heated to a su?icient degree that by
nected to a thermal responsive element H6 of
45 the switch II4, which" thermal responsive ele
ment has one end anchored at II8 and/a contact
I20 actuated by its other end. The contact I20
is in alignment for engagement with a stationary
contact I22, which stationary contact is connect
50 ed to a main control switch I24 to the other power
supply line wire I26.
The main control switch
I24 has a contact I28 and a cooperating mov
able contact arm I30.
With particular reference to Fig. 3, a power
55 supply line wire I40 is connected through a main
control switch I42 to one end of a starting or
auxiliary ?eld winding I44 and to one end of a
main ?eld winding I46 of a motor I48 having a
rotor I50 ‘that is preferably of the squirrel cage
60 ‘type. The main control switch I42 has a con
tact I52 and a cooperating movable contact arm
I54. The other end of the main ?eld winding I46
is connected to a movable contact arm I56 of
an electromagnetically actuated switch I58, and
the time the rotor has reached a predetermined
speed the thermal responsive element hasv flexed
suiilciently to e?’ect disengagement of the con
tacts 44 and 52, to open the‘ circuit to the auxil
iary ?eld winding, thus switching from the start
ing to the running circuit of the motor. The
heater element 10 is preferably so designed and
positioned that the normal main field winding
current at full load, or less than full load does
not effect ?exure of the thermal responsive ele
ment by an amount su?lcient to cause disengage
ment of the contacts 46 and 54, but it does pro
vide su?lcient heat so that the thermal responsive
element remains su?iciently ?exed to maintain
the contacts 44 and 52 in their disengaged posi
on.
'Such an abnormal condition as a sufficient 60
overload on the motor causes an increase in the
main ?eld winding current that in turn increases
the temperature of the ‘heater element 10, which
increase in temperature flexes the thermal re
the movement of thecontact arm I56 is prefer-U sponsive element to effect this engagement of
The other
end of the auxiliary ?eld winding I44 is connect
ed to a stationary contact I62 that is in align
, ably controlled by a dash pot I60.
ment for engagement with the contact arm I56.
70 An electromagnet I64 is magnetically associated
with the movable contact arm I56 to actuate the
arm, and has one end connected to the contact
arm I56 and its other end connected to one end
of a heater element I66. The other end of the
75 heater element I66 is connected to an end of 9.
the contacts 46 and 54. The disengagement of
these latter contacts opens the circuits between
the main ?eld windings 16 and the power supply
line wire 82 to stop the motor. The circuit will
then remain open until the thermal responsive "
element has cooled su?iciently that the thermal
responsive element ?exes back to its normal posi
tion to permit the contacts to close. If the over—
load or abnormal condition still remains, the mo
tor will then be started and stopped in a similar
3
$117,128
manner. It is desirable that the contacts II and
While the embodiment of the present invention
55 close prior to, or simultaneously with the con
as herein disclosed, constitutes a preferred form,
tacts l6 and 5|. so that the main ?eld winding it is to be understood that other forms might be
alone will not be connected across the power sup 7 adopted, all coming within the scope of the claims
ply line wires 80 and 82 when the motor is stopped. which follow.
What is claimed is as follows:
The circuit shown in Fig. 2 operates in a man-,
ner similar to that described for Fig. 1, except
1. In combination, a motor having main and
that separate control switches having separate auxiliary ?eld windings and circuits therefor, and
thermal responsive elements are utilized to ac
complish the starting and the overload control.
a switch comprising a thermal~responsive ele
ment. a heating element in heat transferring re
In this instance. the thermal responsive elements . lation to the thermal-responsive element. and a
pair of cooperating contacts one of which is actu
differ in characteristics. so that the thermal rc
sponsive element I04 and the heater element I in
effect control of the starting and running cir
15 cuits; while ‘the switch H4 remains closed until
some abnormal condition. such as an excessive
overload on the motor. occurs. Switches such as
that illustrated in Figs. 1 to 4 inclusive. of my
previously mentioned copcnding application 740.
961, having thermal responsive elements with dif
ferent operating characteristics are adapted to be
used in asystem such as that illustrated in Fig. 2.
ated by the thermal-responsive element to e?'ect
engagement and disengagement of the contacts.
said contacts being connected in the circuit of 15
the auxiliary ?eld winding to control the starting
and running of the motor, said thermal-respon—
sive element being connected in series with only
the auxiliary ?eld winding and said heating ele
ment being connected in the circuit of the main
?eld winding.
2. In combination. a motor having main and
_ The circuit illustrated in Fig. 3. operates in a
auxiliary ?eld windings and circuits therefor, and
manner similar to thatof the circuit of Fig. 2.
except that a dash pot controlled magnetic switch
is utilized vfor controlling the circuit of the start
a switch comprising a thermal-responsive ele»
ing or auxiliary ?eld winding I“.\
From the foregoing description of the construc
tion and mode of operation of the present control
.80 system. it will be apparent that in one aspect the
system comprises chie?y a motor, (14 in Fig. 1
and 98 in Fig. 2) having main and auxiliary ?eld
windings (15 and ‘I2 in Fig. 1 and 94 and 92 in
Fig. 2. respectively) and. circuits therefor. and a
switch comprising a thermal-responsive element
H6 ‘in Fig. 1 and i0‘ in Fig. 2). a heating ele
ment (10 in Fig. 1 and Ill in Fig. 2) in heat
transferring relation to the thermal-responsive
element (IS in Fig. l and HM in Fig. 2), and a
pair of cooperating contacts (52 and ‘I in Fig. 1
and Hill and I08 in Fig. 2), one of'which i“
in Fig. 1 and I08 in Fig. 2) is actuated by the
thermal-responsive element (IS in Fig. l and
IN in Fig. 2) to effect engagement and disen
gagement of the contacts (52 and 44 in Fig. 1
and '00- and ‘I08 in Fig. 2). said contacts (52
and 44 in Fig. 1 and Hill and I0! in Fig. 2) being
connected in the circuit of the auxiliary ?eld
winding (12 in Fig. 1 and 92 in Fig. 2) to control
the starting and running circuits of the motor ( H
in Fig. 1 and 96 in Fig. 2). said thermal-respon
sive element (IS in Fig. l and IN in Fig. 2) being
connected in series with only the auxiliary ?eld
winding (12 in Fig. l and 92 in Fig. 2) and said
heating element (‘ID in Fig. 1 and H0 in Fig. 2)
being connected in the circuit of the main ?eld
winding (16 in Fig. 1 and 94 in Fig. 2).
It will also be apparent from the foregoing
description of the construction and mode of oper
ation of the present control system that in a
somewhat different aspect of the present inven
tion the system comprises chie?y a motor (H)
ment. a heating element in heat transferring re
lation to the thermal-responsive element, and a
pair of cooperating contacts one of which is actu
ated by the thermal-responsive element to effect
engagement and disengagement of the contacts,
said contacts being connected in the circuit 01.’ the
auxiliary ?eld winding to control the starting and
running of the motor, said thermal-responsive
element being connected in series with only the
auxiliary ?eld winding so ,as to be heated by the
current ?ow through the auxiliary ?eld winding
and said heating element being connected in
series with the main ?eld winding to impart heat
to the thermal-responsive element substantially
proportional to the current ?ow through the
main ?eld winding.
'
3. In combination, a motor having main and
auxiliary ?eld windings and circuits therefor, and
a switch comprising a thermal-responsive ele
ment, a pair of stationary contacts insulated from
each other, a‘pair of movable contact carrying 46
members each having a contact‘ thereon for en
gagement with one of the stationary contacts re—
sponsive to the action of the thermal-responsive
element. a heater element closely associated with
the thermal-responsive element. said thermal 50
responsive element being connected in series with
only one of the ?eld windings, said heater ele
ment being connected in series with the other of
the ?eld windings. and said contacts being actu
ated at different times by the thermal-responsive 55
element to control the starting and running of
the motor and to protect the motor against over
load.
4. In combination, a motor having a starting
circuit including an auxiliary ?eld winding and a 60
running circuit including a main ?eld winding.
and a switch for controlling the starting and run
having a starting circuit including an auxiliary
ning circuits and protecting the motor against‘
?eld winding .(12) and a running circuit includ
ing a main ?eld winding (18), and a switch for
overload, said switch ‘comprising a thermal-re
sponsive element. a pair of stationary contacts 65
controlling the starting and running circuits and
protecting. the motor against over-load. said
switch comprising a thermal-responsive element
(It). a pair of stationary contacts (52 and 54)
70 insulated from each other. and a cooperating pair
of movable contacts (44 and 46 respectively), each
insulated from each other, and a cooperating pair -
of movable contacts each engageable with one of
the stationary contacts. said movable contacts
being controlled by the thermal-responsive ele
ment.
cngageable with one of the stationary contacts
5. In combination. a motor having “a starting
circuit including an auxiliary ?eld winding and
(5! and 54 respectively). said movable contacts
(44 and 46) being controlled by the thermal
a running circuit including a main ?eld winding,
and aswitch for controlling the starting and run
75 responsive element ( I 6) .
70
ning circuits and protecting the motor against 75
4
9,117,128
overload, said switch comprising a thermal-re~ )element, said second set of contacts being con
sponsive element connected in series with the nected in the circuit of the running winding, and
auxilary ?eld winding, a pair of stationary con
tacts insulated from each other, a cooperating
pair of movable contacts each engageable with
one of the stationary contacts, and a heater ele
ment associated with the thermal-responsive ele
a heater elementv connected in series with the
main ?eld winding, said heater element being lo
cated adjacent the, thermal-responsive element
to heat the thermal-responsive element and et
ment and connected in series with the main ?eld
case of an overload on the motor.
winding, the heat generated in thethermal-re
7. In combination, a motor having starting
and running windings, and a switch having a 10
thermal-responsive element and a pair of con
tacts, one of which contacts is actuated by the
thermal-responsive element to effect engagement
10 sponsive element itself mainly effecting operation
of the switch to open one pair of contacts, and
the heat generated in the heater element holding
15
said pair of contacts open while the motor con
tinues to run normally and effecting operation of
the other set of contacts in the event of and ab
normal condition of motor operation.
6. In‘combination, a motor having starting and
running windings and circuits therefor, a switch
having a pair of contacts for controlling the cir
20 cuit of the starting winding, said switch having'a
thermal-responsive element connected in series
with the starting winding for actuating the con
tacts, said thermal-responsive element being re
sponsive to starting winding current when the
26 motor is starting, a second set of contacts on the
switch also actuated by the thermal-responsive
iect actuation of the second set of contacts in
and disengagement of the contacts, said contacts
and thermal-responsive element being connected 15
in series with only one of said windings to effect
disengagementtof the contacts responsive to the
current ?ow through the winding with. which the
thermal-responsive element is in series during
starting of the motor, and means‘ connected in 20
series with the other of said windings for main
taining the contacts in disengaged relation after
the motor is started and until the current ?ow
through the said other of said windings is consid
erably diminished.
25
CALVIN J. WERNER.
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