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Патент USA US2408370

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Patented Oct. 1, 1946
UNITED STATES PATENT OFFICE
2,408,369
MOTOR CONTROL
Cornelius
Brongers'ma, Muskegon Heights, Mich.,
assigner to Manning,
Maxwell &
Inc.,
Muskegon, Mich., a corporation of Moore,
New Jersey
Application April 13, 1944, `Serial No. 530,878
6 Claims.
(Cl. 172-279)
2
To provide quick and relatively sudden reversal
of a motor of the type described, it is necessary
quickly to reestablish the starting circuit for re
verse rotation without allowing time for the ro
10
there is space displacement and
fields displaced in 'space and phase. In the use
oi this class of motors, it is usual to have both
windings which are not normally con
nected, so that induced current ñows through a
closed circuit including the windings while and
after the
‘
rupted, a
20 diminishes the speed of the rotor.
An additional consideration is encountered in
the contemplation of reversible motors which de
starting winding. The latter or electrical type of 25
control is preferred for use in conjunction with
this invention.
Some motors of the
30
ings are interchanged between the starting and
running functions for effecting reversal by varia
tion of the winding characteristics of the two
field windings.
A general object of this invention is to provide
an effective and relative simple system for ef
fecting control and quick reversal of a single
The latter are commonly referred to
in the art as “three lead” motors. When separate 35 phase induction motor of the type having two
leads are provided for making connections to
ñeld windings permanently connected together
and only three external connecting leads.
each end of each ofthe windings, reversal of the
direction of rotation of the motor may be ef
It is also an object of this invention to provide
fected by reversal of the current ñow through one
a system of motor control for single phase induc
of the windings with respect to that through the 40 tion motors which includes switching means for
other of the windings. However, when the wind
interchanging the starting and running winding
ings of the motor have a common connection, the
reversal of the power source connections to one
functions of the two field windings to effect re
versal of the motor operation and for coinciden
winding reverses the current flow through the
tally altering the connections of the motor start
other winding and the direction of rotation ‘re 45 ing control switch to effect control of the selected
mains the same. VWith motors of the latter type
starting winding.
which have a common connection between the
Another object of this invention is to provide
windings, and particularly in view of the system
a system of motor control for single phase alter
of control which is comprehended by this inven
tion, the windings should be adapted to inter 50 nating current motors in which windings having
different characteristics are alterna-ted between
changeable use as starting and main or running
starting and running circuit
windings. Reversal of the use of the windings as
reversal of the direction of rotation and which
starting and running windings eiîects reversal of
the direction of rotation».
utilizes a single control relay for controlling the
55
motor starting circuit to either one ci the wind
2,408,369 \
3
ings which is serving as a starting winding for the
selected direction of rotation.
Another object of this invention is to provide
4
end connected to the common terminal i4 of the
iield windings Il and i2, and its other end con
nected to the contacts 23 and 25 through resistors
30 and 32 respectively. The contacts i6 and H
a system ci motor control adaptable to single 5 of the starting circuit control relay i8 are pref
phase motors of the type having permanently
erably normally closed and are biased into en
connected field windings and a voltage responsive
gagement by means such as a spring 33. The
relay for controlling the starting winding circuit,
contacts are adapted to be opened by the action
and which system includes switch means for
of the electromagnetic actuating Winding 29.
quickly effecting reversal of the direction of ro
Operation of the movable switch elements 2€!
tation of the motor and causes establishment of
and 24 to one position by actuation of the com
a dynamic braking circuit for damping motor ro
mon actuating member 2l connects the power
tor movement during the operation of the switch
supply line lead 28 to one end of the field wind
ing Il through the contact 22 and connects the
means.
Other objects and advantages of the invention
actuating electromagnet 2@ across the field wind
will become apparent as the following description
ing l2 through the resistor 32 and contact 25.
proceeds, taken in connection with the accom
In this instance, the field winding l2 serves as
panying drawing in which the single iigure of the
a starting winding and the field winding i l serves
drawing is a schematic circuit diagram which
as a main or running winding. The starting cir
cuit to the ~field winding l2 is established from
illustrates the preferred embodiment of this in
the power supply line lead 28 through the nor
vention.
While the invention is susceptible of various
mally closed contacts Iii and Vi of the starting
circuit control relay and through the reactor or
modiiications and alternative constructions, I
have sh-own in the drawing and will herein de
condenser IAS. As is usual with motors of this
scribe in detail the preferred embodiment, but it
type, the actuating electromagnet 29 eñects open
is to be understood that I do not thereby intend 25 ing of the contacts I6 and l1 when the motor
to limit the invention to the specific form dis
rotor has attained .a predetermined speed. In
closed, but intend to cover all modiñcations and
this instance, the actuating electromagnet 29 is
alternative constructions falling within the spirit
responsive to the potential across the ñeld wind
ing I2, which potential increases as the rotor
30
appended claims.
speed increases.
>Referring to the drawing, a single phase alter
Even when the power supply circuit to the
nating current motor of the induction motor
running winding l l is opened, the induced poten
tial in the starting winding decays quite slowly.
type has a rotor l0, which is preferably of the
usual squirrel cage variety, and field windings Il
Accordingly, if the relay winding 29 remains con
35
and l2 associated with the rotor. The field wind
nected across such winding l2, the relay con
ings ll and I2 are displaced in space and are
tacts i6 and l1A will not close promptly upon open
adapted to create magnetic fields which are dis
ing of the running winding power circuit. It is
placed in space and phase. In a reversible motor
to overcome the diniculty which would result in
of the type herein considered, the held windings 40 connection with quick reversal due to the slow
ll and l2 may have similar characteristics when
decay of starting winding potential that contact
similar operating characteristics are desired for
25 is provided for opening the circuit to the relay
and scope of the invention as expressed in the
both directions
stances, such as
one direction of
windings i l and
of rotation. But, in other in
winding 2'9 at the same time the contact 22 opens
where more torque is desired in
the power circuit to the running winding Il.
rotation than in the other, the 45 Actuation of the movable switch elements 20
i2 may differ. Both of the field
and 24 to the “off” or neutral position intermedi
windings are adapted for use either as a start
ate their respective contacts while the motor is
ing winding or as the lmain or running winding of
running opens the energizing circuit to the actu
ating electromagnet 29 and thereby effects clo
the motor.
In the preferred embodiment which is disclosed, 50 sure of the contacts I6 and l1 to close a circuit
the field windings ll and I2 are connected to
between the unconnected ends of the ñeld wind
gether permanently at a common terminal Hi to
ings ll and l2 through those contacts and the
constitute a so-called “three lead” motor. One
reactor or resistor I9. 'The iield windings i I and
power supply line lead l5 connected to the com
l2, being connected together at i4 and having a
mon terminal ifi of the two field windings. The 55 circuit formed between their other ends through
other end of the winding l l is connected through
the reactor or condenser le while the rotor is
contacts lio“ and il of a starting circuit control
running, form a closed circuit for the circulation
relay i8 to one side of a reactor or condenser
of currents induced by the rotor in the ñeld wind
i9 as well as to a movable switch element 2i!
ings and thus produce a dynamic braking action
which is adapted alternately to make connections 60 which tends t0 reduce the rotor speed. It is a
with contacts 22 and 23. The other end of the
feature of this circuit that the dynamic braking
field winding l2 is connected to the other side
circuit is closed and established immediately upon
of the reactor or condenser i9 and to a movable
switch element 2li which is adapted alternately
opening of the power supply line- circuit to stop
the motor after its operation in either direction.
to make connections with contacts 25 and 26. 65 When the power supply line lead 28 is con
nected to the ñeld winding i2 by engagement of
The movable switch elements 20 and 24 are co
incidentally operated by a common actuating
member 21. A second power supply line lead 28
the contact 26 with the movable switch element
24, that field winding I2 serves as a main or run
is connected to the contacts 22 and 2B so that that
ning winding of the motor while the field winding
power supply line lead may be selectively and al 70 Il serves as the starting winding. This reversal
ternately connected directly to the field winding
of the use of the windings reverses the direction
Il by engagement of the movable switch element
of rotation of the rotor. When the field winding
20 with the contact 22 and to the ñeld winding i2
i2 serves as the main or running winding, the
by engagement of the movable switch element 2li
starting circuit to the ñeld winding Il is estab
with the contact 26. An actuating electromagnet 75 lished from the power supply line lead 28 through
2‘9 of the starting circuit control relay I3 has one
12,408,369
the contact 2E, reactor or condenser I9, and nor
Ymally closed contacts >Iiì and I‘I. In this in
stance, the actuating electromagnet
29 is con-.
nected across the ñeld winding I I, _through the
.
6
ing selective alternations of the ñeld winding lto
which said electromagnetic actuating winding is
connected, and compensating means in the cir
resistor 39 and the contact 23 which engages the
cuit of said electromagnetic actuating winding
movable switch element 2li.
providing compensation for the dilîerence of char
acteristics of said ñeld windings.
The resistors 30 and 32 may be used in the cir
cuit, as illustrated, to limit the current flow
through the actuating electromagnet 29 but their
principal function is that of equalizing the oper
ating current values in the actuating electromag
net 29 when the ñeld windings II and I2 have
dissimilar characteristics. That is, the resistor
32 limits the current flow through the actuating
electromagnet 29 when the ñeld winding I 2 serves
as a starting winding and the resistor 39 limits
the current through the actuating electromagnet
29 'when the ñeld winding II serves as a starting
winding. The values of the resistors 39 and 32
are predetermined and established in such a way
that the current now through the actuating elec
tromagnet 29 reaches the predetermined value
2. In a control for eíïecting quick reversal of
a single phase alternating current motor includ
ing
a rotor, a pair of cooperating iield windings,
10
and a condenser adapted to be connected in se
ries with one of the iield windings during start
ing, the combination of a pair of power supply
line leads through which operating current is
supplied to the motor, switching means for se
lectively alternating the one of said field wind
ings which receives power from the power sup
ply line leads directly and the one which receives
power from the supply line leads through said
condenser to effect selective reversal of the rotor
20 rotation, a voltage responsive relay having con
tacts connected in series with the condenser and
a voltage responsive electromagnetic actuating
for effecting actuation of the relay I3 at a rotor
winding for automatically controlling the start
speed value which accompanies the use of either
ing and running of the motor in each direction
of the dissimilar iield windings II and I2 as
starting windings. It is a feature of this pre 2, and said switching means including coincident
ally operated means for connecting said electro
ferred circuit that the operating current of the
magnetic actuating winding across the one of said
actuating electromagnet 29 may be predetermined
neld windings which receives power through said
by the resistors 30 and 32 to accomplish the de
condenser.
sired operation of the starting circuit control
relay I8 when either of the field windings is used
3. In a control for eiTecting quick reversal of
a single phase alternating current motor includ
as a starting winding and even when those ñeld
ing a rotor, a pair of cooperating Iield windings
windings have diiïerent characteristics for pro
ducing dissimilar operating characteristics of the
having different characteristics, and a condenser
motor in the two directions of rotation.
adapted to be connected in series with one of
35 the ñeld windings during starting, the combina
It is also a feature of this preferred circuit
tion of a pair of power supply line leads through
that two factors contribute to quick reversal of
which operating current is supplied to the mo
the motor. In the first place, the quick shifting
tor, switching means for selectively alternating
of the common actuating member 21 from one
the one of said iìeld windings which receives
operating position to the other, to eiïect reversal
power from the power supply line leads directly
of the motor, opens the circuit to the actuating
and the one which receives power from the sup
magnet 29 in the intermediate position and there
ply line leads through said condenser to effect
by effects immediate closure of the starting cir
selective reversal of the rotor rotation, a volt
cuit contacts I6 and I7 for establishment of the
age responsive relay having contacts connected
starting circuit for reverse operation. In the
in series with the condenser and a voltage re
second place, this closure of these contacts I6 and
I1 establishes a dynamic braking circuit through
the Iield windings II and I2, the reactor or ‘on
denser I9, and the contacts I6 and I1. The re
sponsive electromagnetic actuating winding for
automatically controlling the starting and run
ning of the motor in each direction, said switch
sulting dynamic braking tends to reduce the rotor 50 ing means including coincidentally operated
means for connecting said electromagnetic ac
speed during the interiml between the opening
of the circuit for one direction of operation and
the closing of the circuit which starts the motor
tuating winding across the one of said neld wind
ings which receives power through said condenser,
and compensating means adapted to equalize the
in the reverse direction; the dynamic braking
circuit being established whenever the movable 55 voltage applied to said actuating winding from
the iìeld windings.
switch elements 2D and 24 are actuated to the
“off" position. The motor acts as a brake to ef
4. In a reversing control for a three lead, single
phase, alternating current motor having a pair
fect quick stopping of the rotor, as well as to
of ñeld windings with one terminal of each con
assist in reducing the rotor speed for aiding quick
reversal of the motor.
nected to a common lead and the other termi
60
nals of said windings connected to separate ones
I claim as my invention:
of the other two leads, the combination of a
l. In a control for effecting quick reversal of
starting relay having a voltage responsive actu
a single phase alternating current motor includ
ating winding and a pair of normally closed con
ing a rotor, a pair of displaced neld windings con
nected together at one end and having different
tacts, a phase shifting device, means for con
characteristics, the combination of a power sup
necting said phase shifting device across said
ply line lead connected to the connected ends of
other two leads in series with said contacts, and
the field windings, a starting circuit control re
means including a reversing switch having an
lay having an electromagnetic actuating wind
ing, a second power supply line lead, switching
means for selectively alternating the connection
of the other ends of the ñeld windings to said
second power supply line for effecting selective
reversal of the rotor rotation, said switching
‘oîT” position and alternatively available “on”
positions for connecting alternate ones of said
other two leads and said common lead to a source
of current in its “on” positions and simultane
ously connecting said relay winding between the
means having contacts for coincidentally eñect 75 remaining one of said other pair of leads and
said common lead and for open-circuiting said
2,408,369
7
relay winding as well as both of said motor wind
ings in its “off” position.
5. In a reversing control for a three lead,
single phase, alternating current motor having
a pair of i-leld windings'with one terminal of each
connected to a common lead and the other two
terminals of said winding connected to separate
ones of the other two leads, the combination of
a phase shifting device, a starting relay having
a voltage responsive actuating winding and a pair
of normally closed contacts, means connecting
said phase shifting device across said other two
leads in series with said contacts, means for con
necting said common lead to one of a pair of
single phase alternating current power lines,
means including a reversing switch having an
“off” position and alternatively available “on”
8
other power line, whereby closure of said con
tacts incident to sh‘ft of said reversing switch
_ to its “oil” position serves to connect both motor
windings in series with each other and said phase
shifting device for dynamic braking of the motor.
6. In a reversing control for a single phase,
alternating current motor having a pair of ñeld
windings, the combination of a phase shifting
device, means including a reversing switch for
connecting alternative ones of said windings
across a source of potential to operate as running
windings for corresponding opposite directions
of motor rotation and with the other winding of
the pair in each instance connected across such
source in circuit relation with said phase shifting
device to operate as a dephased starting winding,
means operable automatically upon attainment
of a predetermined speed of the motor for dis
abling said phase shifting device, and means op
positions for connecting alternate ones of said
other two leads to the other of said pair of power
erable automatically upon actuation oi said re
lines in its “on” positions and simultaneously 20 versing switch from forward to reverse position
connecting said relay winding between the re
therefor or vice versa for eiiecting restoration
maining one of said other pair of leads and said
of said phase shifting device to the circuit.
common lead and for open-circuiting said relay
winding in its “ofi” position as well as for discon
CORNELIUS BRONGERSMA.
necting both of said other two leads from said 25
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