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Патент USA US2068494

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Jan. 19, 1937.
Q w KUHN ET AL
2,068,494
ELECTRICAL CONTROL DEVICE
Filed Nov. 2, 1931
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2,068,494
Patented Jan. 19, 1937
UNITED STATES
_
PATENT OFFICE '
2,068,494
ELECTRICAL CONTROL DEVICE
Clarence Wilbur Kuhn and Clyde F. Robbins, Mil
waukee, Wis., assignors to Cutler-Hammer,
Inc., Milwaukee, Wis., a corporation of Dela
ware
Application November 2, 1931, Serial No. 572,586? ?
5 Claims. (01. 175-7335)
This invention relates to electrical control de
- vices and is particularly applicable to starting
devices for electric motors.
The copending application of William C.
Stevens and George J. Meuer, Serial No. 309,537,
?led October 1, 1928, discloses a push button
operated starting device for electric motors in
ciuding a pair of contact elements, one 'of which
is normally open and is operable to control line
10 connections for the motor, and the other of
which is normally closed and is operable to con
trol a starting resistance in the motor circuit.
The contact elements are provided with an op
erating mechanism including start and stop push
16 buttons and upon depression of the former push
button both of said contact elements are moved
out of normal position with a snap action to es
tablish line connections for the motor and to in
clude the starting resistance in the motor cir
cuit. Immediately upon release of the start
trated and that certain features of the invention
are capable of use in connection with control
devices of various types other than that shown
in the drawing.
In the drawing,
Figure l is- a front elevational view of a motor
starter embodying the invention.
'
Fig. 2 is a side elevational view of the starter
shown in Fig. 1, together with a sectional View
of an enclosing casing therefor.
10
Fig. 3 is a sectional view taken substantially
on line 3-3 of Fig. 1.
~
Fig. 4 is an enlarged sectional view of an elec
tromagnetic restraining device shown in Figs. 1,
2 and 3.
15
Figs. 5 and 6 are end views of the core member,
of the electromagnetic restraining device shown
in Fig. 4, illustrating such core member in dif
ferent positons with respect to its cooperating
armature member, and
20
Fig. '7 is a diagrammatic view illustrating the
push button the resistance controlling contact
element returns to normal position to shunt the circuit connections for the starter shown ?in
Fig. 1.
starting resistance and the other contact ele
The starting device illustrated is provided with
ment is heldin closed position to maintain line
a switch mechanism of the character disclosed 25
connections
for
the
motor
by
a
latching
mech
25
in the aforementioned copending application of
anism which is releasable by the stop push but
William C?. Stevens and George J. Meuer. Such
ton.
The present invention relates to motor starters ?' mechanism includes a pair of U-shaped contact
of the aforesaid character, and has among its levers l and 2 arranged in opposed relation and
objects to provide automatic means which acts having their adjacent ends pivotally mounted 30
so upon
momentary depression of the start push upon bearing projections 3 and 4 formed?upon
a-U-shaped bracket 5 ?xed to an insulating base
button to delay return of the resistance control
ling element to normal position for an interval 6. ? Each of the contact levers i and 2 has an
which is su?icient to prevent excessive current insulated bridging contact mounted upon the
free end thereof, the bridging contact 1 asso 35
in
the motor circuit upon exclusion of the start
35
ciated with lever I being adapted to cooperate
ing resistance.
with
a pair of stationary contact devices 8--8
Another object is to ?provide a starting device
for alternating current motors having improved and the bridging contact 9 associated with lever
electromagnetic means associated therewith for 2 being adapted to cooperate with a pair of sta
tionary contact devices Ill-40. As shown in 40
40 automatically timing interruption of starting Fig. '1, the two pairs of contact devices 8-8 and
connections and establishment of rurming con- l0-?lll are mounted upon opposite ends of in
nections in accordance with predetermined cur
sulating
base 5. Each of the contact devices
rent conditions in the motor circuit.
8-8 is provided with a contact ?nger 8EL to be
Another object is to provide an improved elec
engaged by bridging contact ?I when lever i oc 45
46 tromagnetic restraining device which is adapted cupies the position shown in Fig. 2, and each of
for use in connection with alternating current
motor starters and control devices of other types the contact devices Ill-l0 is provided we a
contact ?nger Hi?1 to be engaged by bridging con
and which is readily adjustable to vary the re
tact 9 when lever 2 occupies the position shown
straining effect thereof.
I
50
in Fig. 3.
Various
other
objects
and
advantages
of
the
50
The operating mechanism for contact levers l
invention will hereinafter appear.
and 2 includes a tension spring I2 which iscon
The accompanying drawing illustrates an em
bodiment of the invention which will now be nected at opposite ends to the free ends of con
tact levers I and 2 by insulating links I3. As is
described, it being understood that various mod
apparent from Fig. 3, movement of the axis of 55
i?cations may be made in the embodiment illus
20
2
2,068,494
spring l2 in opposite directions across a plane
joining bearing projections 3 and 4 provides for
snap movement of contact levers I and 2 in oppo
site directions between the positions illustrated
in Figs. 2 and 3. Spring l2 passes through an
opening in a reciprocable operating member I4
having a push button I5 ?xed to the outer end
thereof. Operating member I4 is supported ad
jacent its inner end within an opening in brack
et 5 and is supported adjacent its outer end with
in an opening in a frame I6 ?xed to said bracket.
A spring I1 biases operating member I4 outward
ly towards the position shown in Fig. 2. Said
spring is held under compression between a wash
15 er I8 mounted upon said member and a plate I9
?xed to the rear face of base 6 by screws I3?
which also serve to secure bracket 5 to said base.
Contact lever 2 has a latch 20 associated there- _
with for locking the same against movement out
20 of the position shown in Fig. 3. Latch 20 is piv
otally mounted upon a pin 2I carried within a
recess in the outer face of frame I6 and the
same is provided with a shoulder 22 for engaging
a projection 23 on contact lever 2. Latch 20
25 is also provided with an inclined cam surface 24
Magnet 30 is mounted upon an insulating plate
3i which also carries the aforedescribed switch
mechanism and resistance element R. Said mag
net has an energizing winding 32 which is
mounted upon a cylindrical core member 33 and
said core member is secured to plate 3| by a screw
34 which passes through said plate from the
rear thereof into a centrally located tapped
opening in the rear end of said core member.
The outer end of core member 33 projects beyond 10
winding 32 and is slotted at 35 to provide a pair
of pole projections 36 and 31 for attracting a
projecting armature member 38 ?xed to the free
end of contact lever I. The pole projection 35
is surrounded by a plurality of D-shaped shad 15
ing coils 39 which are secured to said projection
by turned over portions 40 on the end of the
latter.
These shading coils are adapted to act
in a well known manner to prevent chattering
of the armature member 38 upon core member 20
33 by producing magnetic fluxes of different
phase in the pole projections 36 and 31.
As hereinbefore set forth, magnet 30 serves to
prevent return of contact element I to normal
position until the current in the motor circuit 25
to be engaged by a reciprocable tripping member drops to a value such as to prevent an excessive
25 having its inner end supported within an open ' current rush in the motor circuit upon exclusion
ing 25 in base 6 and having its outer end pro
of the starting resistance element R. In prac
vided with a push button 21 which is supported tice it is desirable to provide for adjustment of
30 within an opening in frame I6. Tripping member the current value at which magnet 30 is adapted
25 is formed to provide a face 25? for engaging to release contact element I, and for this pur 30
the cam surface 24 on latch 20 and said tripping pose said magnet and its cooperating armature
member is connected to said latch by a spring 28.
38 are so designed that by loosening screw 34
Spring 28 serves to bias tripping member 25 out
the magnet may be rotated with respect to the
35 wardly towards the position shown in Fig. 3 and
armature member. The width of the armature
also serves to bias latch 20 upwardly for engage
ment with the projection 23 on contact lever 2.
As is apparent, depression of push button 21
causes the face 25a of tripping member 25 to
40 engage the cam surface 24 on latch 2|] to move the
latter downwardly for release of contact lever 2.
The above described switch mechanism may be
connected as shown in Fig. 7 to effect starting
and stopping of an electric motor M.
As is ap
45 parent from the foregoing, upon depression of
push button I5 contact levers I and 2 are moved
with a snap action from the positions shown in
Fig. 2 to the positions shown in Fig. 3 to there
by move bridging contact 9 into engagement with
50 its cooperating stationary contacts IlJ"--~II)n and
bridging contact 1 out of engagement with its
cooperating stationary contacts 8L4?. With the
circuit connections shown in Fig. 7 motor M is
then connected across a source of current in55 dicated by lines L1?L2 in series with a starting
resistance element R and a magnet 30 which
will be hereinafter more fully described. Upon
release of push button I5 contact lever 2 tends
to return to the position shown in Fig. 2 to dis
60 connect the motor from the supply circuit but
the same is held in the position shown in Fig. 3
by its associated latch 20 which is adapted to be
tripped as hereinbefore set forth upon depression
of push button 21. Also upon release of push
65 button I5 contact lever I tends to return imme
diately to the position shown in Fig. 2, in which
position bridging contact 1 engages its cooperat
ing stationary ?contacts lie-8? to exclude the
starting resistance element R and magnet 30
70 from the motor circuit. However, magnet 30
serves to hold contact lever I in the position
shown in Fig. 3 until the current in the ?motor
circuit drops to a value such as to prevent an
excessive current rush upon exclusion of resist
75
ance\element R.
35
member 38 is less than the diameter of the core
member 33 and by rotating the magnet with re
spect to the armature member the area of the
face on pole projection 31 which is overlapped by
the armature member 38 can be varied as shown 40
in Figs. 5 and 6. As is apparent, the reluctance
of the magnetic circuit between pole projection
31 and armature member 38 can thus be ad
justed to vary the current value at which magnet
30 is adapted to release its cooperating arma
45
ture member 38. Also as is apparent, rotative
adjustment of the magnet about its axis varies
the distance of the pole faces of pole projec
tions 31 and 38 from the pivot of contact element
I to also effect variation of the current value
at which said armature is released.
In manufacturing the aforedescribed switch
mechanism the angular position of the armature
member 38 with respect to the core member 33
is likely to vary, as indicated by full and dotted
lines in Fig. 4. This tends to vary the holding 55
effect of the magnet 33 upon the armature mem
ber. However, in practice it has been found
that by maintaining an air gap between pole
projection 31 and the armature member 38 vari
ations in the angular position of armature mem
ber 38 with respect to core member 33 will pro
duce only a negligible variation in the holding
effect of the magnet upon the armature mem
ber. As shown in Fig. 4 in order to maintain
an air gap between pole projection 31 and the
armaturemember 38, pole projection 35 projects
beyond the former pole projection and serves as
an abutment for said armature member.
The aforedescribed switch mechanism is pref
erably mounted within a box shaped enclosing
casing II which is provided with a cover 42 hav
ing openings therein for receiving the push but
tons I5 and 21. Also if desired the latch 28 may
be provided with overload tripping means of the y.
2,068,494
character disclosed in the copending applica
tion of Clarence W. Kuhn, Serial No. 460,461,
?led June 11,? 1930. The tripping means dis
closed in this application is of the electrothermal
type and is adapted to respond upon overloads
in the motor circuit to trip latch 20 for stopping
of the motor and is also adapted to be reset by
the switch operating mechanism.
What we claim as new and desire to secure by
10 Letters Patent is:
1. The combination with a control device in
cluding a movable control part, of a holding wind
ing therefor to be supplied with alternating cur
rent, a core member for said winding having a
15 shading coil associated therewith to provide mag
netic fields of different phase for attracting said
control part to hold the same in a given position,
and supporting means for said core member ,per
3
said armature member, a shading coil associated
with said core member and surrounding one of
the divisions thereof, and supporting means for
said members permitting relative adjustment of
said armature and core members to vary the
overlap of said armature member with respect to
certain of. the pole faces on said core member
for variation of the holding effect of said winding. 4. The combination with a control device in
cluding a movable control part having an arma 1O
ture member associated therewith, of a holding
winding therefor to be supplied with alternating
current, a core for said winding divided to pro
vide a pair of pole projections having pole faces
to cooperate with an overlapping pole face on 15
said armature member, one of said pole projec
tions being adapted to abut said armature mem
ber and to maintain an air gap between said
mitting rotary adjustment thereof about its axis
20 for variation of the holding effect of said mag
netic ?elds upon said control part.
armature member and the other of said pole
projections, a shading coil \surrounding said 20
former pole projection, and supporting means for
2. The combination with a control device, in
cluding a movable control part biased towards
a given position, said part having an armature
25 member associated therewith, of an alternating
current electromagnet for attracting said arma
ture member to hold said control part in another
position, said magnet having means associated
therewith to provide magnetic ?elds of different
said core permitting adjustment thereof with re
spect to said armature member to vary the over
30 phase for attracting said armature member, and
a support for said magnet permitting adjustment
thereof with respect to said armature member
to provide for variation of the reluctance of one
of said magnetic fields without substantial vari
35 ation of the reluctance in the other of said mag
netic ?elds.
_
3. The combination with a control device in
cluding a movable control member having an
armature member associated therewith, of a
40 holding winding therefor to be supplied with
alternating current, a core member for said
winding divided to provide a plurality of pole
faces to coact with an overlapping pole face on
lap of said armature member withv respect to
the pole face' of said last mentioned pole pro 25
jection.
5. The combination with a control device in
cluding a movable control element having means
associated therewith for biasing the same to
wards a given normal position, of a winding to 30
be supplied with alternating current, and means
associated with said winding to provide ?uxes
differing in phase for attracting said control
element to hold the same in another position,
said means being adjustable with respect to said 35
control element to vary the attractive e?ect of
one of said ?uxes upon said control element with
out substantial variation in the attractive effect
of the other of said ?uxes upon said control
element.
40.
CLARENCE WILBUR KUHN.
CLYDE F. ROBBINS.
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