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Claims  |
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I claim:
1. An electrical contactor, comprising:
first contact means;
second contact means for being moved into a disposition of electrical
continuity with said first contact means;
electromagnet means with movable armature means which is mechanically
interconnected with said second contact means for moving said second
contact means into said disposition of electircal continuity with said
first contact means in response to the flow of current pulses through a
winding of said electromagnet means which current pulse are driven by
controlled voltage pulses the amplitude which is free to vary within
limits;
spring means disposed to resist the movement of said armature means, the
resistance being overcome when a predetermined minimum amount of kinetic
energy is applied to said armature means; and
means for supplying electrical power to said winging of said electromagnet
means, wherein N of said controlled voltage pulses are provided to said
winding, where one of said pulses is conduction angle controlled and
adjustable as a function of said voltage amplitude so that the total
amount of said kinetic energy which is supplied to said armature means
during movement thereof as the result of said electrical current pulses
flowing in said winding is substantially equal to said predetermined
minimum amount of kinetic energy.
2. The combination as claimed in claim 1 wherein a microprocessor controls
said conduction angle.
3. The combination as claimed in claim 2 wherein a menu of possible voltage
amplitudes and related conduction angles is stored in memory location in
said microprocessor for determining the conduction angle to be used as a
function of the actual voltage amplitude.
4. The combination as claimed in claim 1 wherein N equals 2.
5. The combination as claimed in claim 1 wherein said current pulses are
are provided by a full wave rectifier.
6. The combination as claimed in claim 1 wherein all of said N voltage
pulses are conduction angle controlled.
7. The combination as claimed in claim 1 wherein said spring is compressed
as it resists the movement of said armature means.
8. The combination as claimed in claim 7 wherein said spring means
comprises a kickout spring which causes said second contact means to mvoe
away from said first contact means upon command to open said electrical
circuit.
9. The combination as claimed in claim 7 wherein said spring means
comprises a contact spring which operates to apply pressure to first and
second contact means when they are in said disposition of electrical
continuity.
10. The combination as claimed in claim 9 wherein said spring means
comprises a kickout spring which causes said second contact means to move
away from said first contact means upon command.
11. An electrical contactor, comprising:
movable armature means;
fixed armature means cooperable with said movable armature means to define
an air gap therebetween;
electromagnet coil means cooperable with said movable armature means and
said fixed armature means to cause said movable armature means to move
toward said fixed armature means in response to the controlled flow of
electrical current pulses in said electromagnet coil means until said
fixed armature means and said movable armature means abut, where said
current pulses are driven by controlled voltage pulse having a voltage
amplitude which is free to vary;
spring means disposed to resist the movement of said movable armature means
toward said fixed armature means;
control means for supplying said controlled flow of electrical current
pulses to said electromagnet coil means, said controlled flow of
electrical current pulses accelerating said movable armature means to a
first velocity prior to said movable armature means abutting said fixed
armature means; and
said movable armature means continuing movement to said fixed armature
means as a function of the kinetic energy imparted thereto at said first
velocity, said movable armature means abutting said fixed armature means
at a second velocity which is lower than said first velocity as the
kinetic energy of said armature means is absorbed by said spring means,
wherein N of said controlled voltage pulses are provided to said
electromagnet coil means, where one of said pulses is conduction angle
controlled and adjustable as a function of said voltage amplitude.
12. The combination as claimed in claim 11 wherein a microprocessor
controls said conduction angle.
13. The combination as claimed in claim 12 wherein a menu of possible
voltage amplitudes and related conduction angles is stored in memory
locations in said microprocessor for determining the conduction angle to
be use as a function of the actual voltage amplitude.
14. The combination as claimed in claim 11 wherein N equals 2.
15. The combination as claimed in claim 11 wherein said current pulses are
provided by a full wave rectifier.
16. The combination as claimed in claim 11 wherein all of said N pulses are
conduction angle controlled.
17. The combination as claimed in claim 11 wherein said second velocity is
substantially zero velocity.
18. The combination as claimed in claim 11 wherein one of said conduction
angle controlled voltage pulses is supplied to said electormagnet means at
the time within limits that said movable armature means abuts said fixed
armature means for preventing aramture "bounce".
19. An electrical contactor, comprising:
movable armature means;
stationary abutment means;
electromagnet means with electric coil means for energizing said
electromagnet means in response to controlled electrical energy for
magnetically moving said movable armature means into a disposition of
abutment with said stationary abutment means;
spring means interconnected with said armature means which resist the
movement of said armature means into said disposition of abutment with
said stationary abutment means;
control means for supplying said controlled electrical energy to said coil
means as a function of controlled electrical voltage pulses at a voltage
amplitude which is free to vary, the total mechanical energy required to
compress said spring means as said armature means is moved into said
disposition of abutment with said stationary abutment means being equal to
K;
said control means cooperating with said coil means to supply K electrical
energy to said coil means previous to said armature means abutting said
stationary abutment means, continued movement of said armature means to
said disposition of abutment after said K electrical energy has been
supplied to said coil means being sustained by kinetic energy related to a
velocity V1 imparted to said armature means by said electrical energy,
said armature means thereafter abutting said stationary abutment means at
a second velocity V2 which is less than V1; and
electrical contact means interconnected with said armature means and an
external electrical circuit for being closed as said armature means moves,
wherein N of said voltage pulses are provided to said coil means, where
one of said pulses is conduction angle controlled and adjustable as a
function of said voltage amplitude.
20. The combination as claimed in claim 19 wherein said stationary abutment
means is magnetic.
21. The combination as claimed in claim 20 wherein a microprocessor
controls said conduction angle.
22. The combination as claimed in claim 21 wherein a menu of possible
voltage amplitudes and related conduction angles is stored in memory
locations in said microprocessor for determining which conduction angle to
use as a function of the actual voltage amplitude which drives said
current pulses.
23. The combination as claimed in claim 20 wherein N equals 2.
24. The combination as claimed in claim 20 wherein said voltage pulses are
provided by a full wave rectifier.
25. The combination as claimed in claim 20 wherein all of said N voltage
pulses are conduction angle controlled.
26. The combination as claimed in claim 20 wherein V2 is substantially
equal to zero.
27. The combination as claimed in claim 25 wherein said controlled
electrical energy is provided to said coil means generally in an amount no
greater than K.
28. The combination as claimed in claim 20 wherein said controlled
electrical energy is provided to said coil means generally in an amount no
greater than K.
29. The combination as claimed in claim 20 wherein said spring means
comprises a contactor kickout spring and a contactor contact spring.
30. An electrical apparatus comprising:
first contact means;
second contact means movable into a disposition of electrical continuity
with said first contact means;
electromagnet means with movable armature means which is mechanically
interconnected with said second contact means for moving said second
contact means into said disposition of electrical continuity with said
first contact means in response to the flow of current pulses through a
winding of said electromagnet means which current pulse are driven by
controlled voltage pulses the amplitude which is free to vary within
limits;
mechanical resistance means which resists the movement of said armature
means, the mechanical resistance thereof being overcome when a
predetermined amount of kinetic energy is applied to said movable armature
means; and
means for supplying electrical power to said winding of said electromagnet
means, wherein N of said controlled voltage pulses are provided to said
winding, where one of said pulses is conduction angle controlled and
adjustable as a function of said voltage amplitude so that the total
amount of said kinetic energy which is supplied to said armature means
during movement thereof as the result of said electrical current pulses
flowing in said winding being substantially equal to said predetermined
minimum amount of energy.
31. The combination as claimed in claim 30 wherein a microprocessor
controls and conduction angle.
32. The combination as claimed in claim 31 wherein a menu of possible
voltage amplitudes and related conduction angles is stored in memory
locations in said microprocessor for determining the conduction angle to
be used as a function of the actual voltage amplitude.
33. The combination as claimed in claim 30 wherein N equals 2.
34. The combination as claimed in claim 30 wherein said current pulses are
provided by a full wave rectifier.
35. The combination as claimed in claim 30 wherein all of said N voltage
pulses are conduction angle controlled.
36. An electrical contactor, comprising:
movable armature means;
fixed armature means cooperable with said movable armature means to define
an air gap therebetween;
electromagnet coil means cooperable with said movable armature means and
said fixed armature means to cause said movable armature means to move
toward said fixed armature means in response to the controlled flow of
current pulses in said electromagnet coil means until said fixed armature
means and said movable armature means abut, where said current pulses are
driven by a first set of controlled voltage pulses having a voltage
amplitude which is free to vary within limits;
spring means disposed to resist the movement of said movable armature means
toward said fixed armature means;
control means for supplying said controlled flow of electrical current
pulses to said electromagnet coil means, said controlled current pulses
accelerating said movable aramture mans to a first velocity prior to said
movable armature means abutting said fixed armature means; and
said movable armature means continuing movement to said fixed armature
means as a function of the kinetic energy imparted thereto at said first
velocity and as a function of another controlled voltage pulse which is
applied to said electromagnet current means after said first velocity has
been attained said movable armature means abutting said fixed armature
means at a second velocity which is lower than said first velocity as the
kinetic energy of said armature means is absorbed by said spring means,
wherein N of said first set of voltage pulses are provided to said
electromagnet coil means, where one of said N pulses is conduction angle
controlled and adjustable as a function of said voltage amplitude.
37. The combination as claimed in claim 36 wherein a microprocessor
controls said conduction angle.
38. The combination as claimed in claim 37 wherein a menu of possible
voltage amplitudes and related conduction angles is stored in memory
locations in said microprocessor for determining the conduction angle to
be used as a function of the actual voltage amplitude.
39. The combination as claimed in claim 36 wherein all of said N pulses are
conduction angle controlled.
40. The combination as claimed in claim 36 wherein said second velocity is
substantially zero velocity.
41. An electrical contactor, comprising:
movable armature means;
stationary abutment means;
electromagnet means with electric coil means for energizing said
electromagnet means in response to controlled electrical energy for
magnetically moving said movable armature means into a disposition of
abutment with said stationary abutment;
spring means interconnected with said armature means which resists the
movement of said armature means into said disposition of abutment with
said stationary abutment means;
control means for supplying said controlled electrical energy to said coil
means as a function of controlled electrical voltage pulses at a voltage
amplitude which is free to vary, the total mechanical energy required to
compress said spring means as said armature means is moved into said
disposition of abutment with said stationary abutment means being equal to
K;
said control means cooperating with said coil means to supply G electrical
energy to said coil means previous to said armature means abutting said
electromagnet means, where G is less than K, continued movement of said
armature means to said disposition of abutment after said G electrical
energy has been supplied to said coil means being sustained by kinetic
energy related to a velocity V1 imparted to said armature means by said
electrical energy G, and as a function of another electrical voltage pulse
which is applied to said electric coil means after said velocity V1 has
been obtained, said armature means thereafter abutting said electromagnet
means at a second velocity V2 which is less than V1; and
electrical contact means interconnected with said armature means and an
external electrical cicuit for being closed as said armature means moves,
wherein N of said voltage pulses are provided to said coil means, where
one of said pulses is conduction angle controlled and adjustable as a
function of said voltage amplitude.
42. The combination as claimed in claim 41 wherein a microprocessor
controls said conduction angle.
43. The combination as claimed in claim 42 wherein a menu of possible
voltage amplitudes and related conduction angles is stored in memory
locatis in said microprocessor for determining which conduction angle to
use as a function of the actual voltage amplitude which drives said
current pulses.
44. The combination as claimed in claim 41 wherein all of said N pulses are
conduction angle controlled.
45. The combination as claimed in claim 41 wherein V2 is substantially
equal to zero.
46. The combination as claimed in claim 41 wherein said spring means
comprises a contactor kickout spring and a contactor contact spring.
47. An electrical contactor, comprising:
movable armature means;
fixed armature means cooperable with said movable armature means to define
an air gap therebetween;
electromagnetic coil means cooperable with said movable armature means and
said fixed armature means to cause said movable armature means to move
toward said fixed armature means until said fixed armature means and said
movable armature means abut;
control means for supplying a half wave electrical current pulse to said
electromagnet coil means, said current pulse holding said movable armature
means to said fixed armature means at the time of abutment to prevent
"bounce", where said pulse is conduction angle controlled.
48. The combination as claimed in claim 47 wherein a microprocessor
controls said conduction angle.
49. An electrical contactor, comprising:
first contact means;
second contact means for being moved into a disposition of electrical
continuity with said first contact means;
electromagnet means with movable armature means which is mechanically
interconnected with said second contact means for moving said second
contact means into said disposition of electrical continuity with said
first contact means in response to the flow of current pulses through a
winding of said electromagnet means which current pulse are driven by
controlled voltage pulses the amplitude which is free to vary within
limits;
spring means disposed to resist the movement of said armature means, said
resistance being overcome when a predetermined minimum amount of kinetic
energy is applied to said armature means; and
means for supplying electrical power to said winding of said electromagnet
means, wherein N of said controlled voltage pulses are provided to said
winding, where one of said pulses is conduction angle controlled and
adjustable as a function of said voltage amplitude.
50. An electrical contactor, comprising:
movable armature means;
stationary abutment means;
electromagnet means with electrical coil means for energizing said
electromagnet means in response to controlled electrical energy for
magnetically moving said movable armature means into a disposition of
abutment with said stationary abutment means;
spring means interconnected with said armature means which resists the
movement of said armature means into said disposition of abutment with
said stationary abutment means;
control means for supplying said controlled electrical energy to said coil
means as a function of controlled electrical voltage pulses at a voltage
amplitude which is free to vary;
said control means cooperating with said coil means to supply electrical
energy to said coil means previous to said armature means abutting said
stationary abutment means, continued movement of said armature means to
said disposition of abutment after said electrical energy has been
supplied to said coil means being sustained by kinetic energy related to a
velocity V1 imparted to said armature means by said electrical energy,
said armature means thereafter abutting said stationary abutment means at
a second velocity V2 which is less than V1; and
electrical contact means interconnected with said armature means and an
external electrical circuit for being closed as said armature means moves,
wherein N of said voltage pulses are provided to said coil means, where
one of said pulses is conduction angle controlled and adjustable as a
function of said voltage amplitude.
51. An electrical apparatus comprising:
first contact means;
second contact means movable into a disposition of electrical continuity
with said first contact means;
electromagnet means with movable armature means which is mechanically
interconnected with said second contact means for moving said second
contact means into said disposition of electrical continuity with said
first contact means in response to the flow of current pulses through a
winding of said electromagnet means which current pulse are driven by
controlled voltrage pulses the amplitude which is free to vary within
limits;
mechanical resistance means which resists the movement of said armature
means, said mechanical resistance thereof being overcome when kinetic
energy is applied to said movable armature means; and
means for supplying electrical power to said winding of said electromagnet
means to overcome said mechanical resistance, wherein N of said voltage
pulses are provided to said winding, where one of said voltage pulses is
conduction angle controlled and adjustable as a function of said voltage
amplitude so that said kinetic energy is supplied to said armature means
during movement thereof as the result of said electrical current pulses
flowing in said winding. |
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Claims |
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Description |
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CROSS REFERENCE TO RELATED APPLICATIONS
The inventions taught herein are related to concurrently filed commonly
assigned copending applications as follows:
Application Ser. No. 016,425 filed concurrently herewith entitled
"ELECTROMAGNETIC CONTACTOR WITH ENERGY BALANCED CLOSING SYSTEM" (W. E.
Case 53,124) by J. A. Bauer.
Application Ser. No. 016,423 filed concurrently herewith entitled
"ELECTROMAGNETIC CONTACTOR WITH CURRENT REGULATED ELECTROMAGNETIC COIL FOR
HOLDING THE CONTACTS CLOSED" (W. E. Case 53,662) by G. F. Saletta et al.
Application Ser. No. 016,412 filed concurrently herewith entitled
"ELECTROMAGNETIC CONTACTOR WITH ALGORITHM CONTROLLED CLOSING SYSTEM" (W.
E. Case 53,127) by J. A. Bauer, D. A. Mueller, R. T. Basnett and J. C.
Engel.
Application Ser. No. 016,426 filed concurrently herewith entitled
"ELECTROMAGNETIC CONTACTOR WITH DISCRIMINATOR FOR DETERMINING WHEN AN
INPUT CONTROL SIGNAL IS TRUE OR FALSE AND METHOD" (W. E. Case 53,663) by
J. C. Engel.
Application Ser. No. 016,422 filed concurrently herewith entitled
"ELECTROMAGNETIC CONTACTOR WITH LIGHT WEIGHT WIDE RANGE CURRENT
TRANSDUCER" (W. E. Case 53,126) by J. A. Bauer.
Application Ser. No. 016,420 filed concurrently herewith entitled
"ELECTROMAGNETIC CONTACTOR WITH LIGHT WEIGHT WIDE RANGE CURRENT TRANSDUCER
WITH SINTERED POWDERED METAL CORE" (W. E. Case 53,664) by J. C. Engel.
Application Ser. No. 016,424 filed concurrenlty herewith entitled
"ELECTROMAGNETIC CONTACTOR WITH UNIVERSAL CONTROL" (W. E. Case 53,665) by
J. C. Engel.
Application Ser. No. 016,421 filed concurrently herewith entitled
"ELECTROMAGNETIC CONTACTOR WITH WIDE RANGE OVERLOAD CURRENT RELAY BOARD
UTILIZING LEFT SHIFTING AND METHOD" (W. E. Case 53,666) by G. F. Saletta
et al.
Application (Ser. No. 016,417 filed concurrently herewith entitled
"ELECTROMAGNETIC CONTACTOR WITH CIRCUIT BOARD SUPPORT SYSTEM" (W. E. Case
53,702) by D. W. Cole and G. E. Pruitt II.
Application Ser. No. 016,415 filed concurrently herewith entitled
"ELECTROMAGNETIC CONTACTOR WITH REDUCED NOISE MAGNETIC ARMATURE" (W. E.
Case 53,703) by R. A. Hurley and B. L. DeVault.
Application Ser. No. 725,179 entitled "ANALOG SIGNAL PROCESSING CIRCUIT,"
filed Apr. 19, 1985 by J. C. Engel.
Application Ser. No. 725,050 entitled "A SUPERVISORY CIRCUIT FOR A
PROGRAMMED PROCESSING UNIT," filed Apr. 19, 1985 by J. C. Engel.
Application Ser. No. 868,834 (W. E. Case 53,378) entitled "MASTER METERING
MODULE WITH VOLTAGE SELECTOR" by D. P. Orange, J. C. Engel, G. F. Saletta,
D. A. Mueller and R. T. Elms.
Application Ser. No. 868,833 (W. E. Case 53,061) entitled "MASTER METERING
MODULE WITH DIGITAL SATURATION ADJUSTER AND METHOD FOR USE THEREOF" by D.
P. Orange, J. C. Engel, G. F. Saletta and D. A. Mueller.
Application Ser. No. 016,420 (W. E. Case 53,364) entitled "PROCESS FOR
MANUFACTURING ELECTRICAL EQUIPMENT UTILIZING PRINTED CIRCUIT BOARDS" by S.
L. Glover.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The subject matter of this invention is related generally to
electromagnetic contactors and more specifically to apparatus for
controlling an electromagnetic contactor.
2. Description of the Prior Art
Electromagnetic contactors are well known in the art. A typical example may
be found in U.S. Pat. No. 3,339,161 issued Aug. 29, 1967 to J. P. Conner
et al. entitled "Electromagnetic Contactor" and assigned to the assignee
of the present invention. Electromagnetic contactors are switch devices
which are especially useful in motor-starting, lighting, switching and
similar applications. A motor-starting contactor with an overload relay
system is called a motor controller. A contactor usually has a magnetic
circuit which includes a fixed magnet and a movable magnet or armature
with an air gap therebetween when the contactor is opened. An
electromagnetic coil is controllable upon command to interact with a
source of voltage which may be interconnected with the main contacts of
the contactor for electromagnetically accelerating the armature towards
the fixed magnet, thus reducing the air gap. Disposed on the armature is a
set of bridging contacts, the complements of which are fixedly disposed
within the contactor case for being engaged thereby as the magnetic
circuit is energized and the armature is moved. The load and voltage
source therefor are usually interconnected with the fixed contacts and
become interconnected with each other as the bridging contacts make with
the fixed contacts. Generally, as the armature is acclerated towards the
magnet, it must overcome two spring forces. The first spring force is
provided by a kickout spring which is subsequently utilized to disengage
the contacts by moving the armature in the opposite direction when the
power applied to the coil has been removed. This occurs an the contacts
are opened. The other spring force is provided by a contact spring which
begins to compress as the bridging contacts abut the fixed contacts, but
while the armature continues to move towards the fixed magnet as the air
gap is reduced to zero. The force of the contact spring determines the
amount of electrical current which can be carried by the closed contacts,
and furthermore determines how much contact wear is tolerable as repeated
operation of the contactor occurs. It is usually desirous for the contact
spring to be as forceful as possible, thus increasing the current-carrying
capability of the contactor and increasing the capability to adapt for
contact wear. However, since this force must be overcome by the energy
provided to the electromagnet during the closing operation, more closing
energy will generally be required for relatively stiffer contact springs
than for less stiff contact springs. Most electromagnets in contactors are
powered by alternating current and, as will be described herein more fully
hereinafter, the magnet pull curve for the electromagnetic armature
accelerating system is generally fixed in shape according to the magnetic
system utilized. In prior art contactors, the amount of energy provided to
the electromagnet is more than is necessary to overcome the force of the
springs against which the accelerating armature operates. One reason for
this is the need to overcome the effect of the relatively stiff contact
springs when the contacts engage. In general, however, the excess energy
is wasted energy which is undesirable. But, perhaps more importantly, the
excess energy is absorbed by the mechanical system as the armature
finishes its closing travel stroke. This excessive kinetic energy is
usually exemplified by heat, noise, vibration, undesirable contact bounce
and shock. It would be desirable, therefore, to find an electrical control
system for an electromagnetic closing system which provided generally only
the amount of energy necessary to overcome the forces which resist
movement of the armature in the closing stroke. It would be desirable if a
feed-forward voltage based control system utilizing a microprocessor could
be found in which initial acceleration of the armature could be
accomplished, it would also be desirable if the control system determined
during the acceleration process whether the amount of electrical energy
supplied to the coil of the electromagnetic was sufficient to continue the
closing operation with approximately the amount of energy necessary to
cause the armature to abut the fixed magnet and if not where the control
system provided an extra shot of energy to continue the operation.
Finally, it would be desirable if where sufficient energy could be applied
to the magnetic coil at about the time that the armature abutted the fixed
magnet to dampen or completely reduce the amount of "bounce" caused by the
closing operation.
SUMMARY OF THE INVENTION
In accordance with the invention an electrical contactor or controller is
taught which includes a first contact means and a second contact means for
being moved into disposition of electrical continuity with the first
contact means. An electromagnet means with a movable armature means is
provided which is mechanically interlocked with the second contact means
for moving that second contact means into the disposition of electrical
continuity with the first contact means in response to the flow of current
pulses through a winding of the electromagnet means, which current pulses
are driven by voltage pulses with a voltage amplitude which are free to
vary within limits. Spring means are provided for resisting the movement
of the armature means. The latter resistance is overcome when a
predetermined minimum amount of kinetic energy is supplied to the armature
means. A means for supplying electrical power to the winding of the
electromagnet means is provided. N of the controlled voltage pulses are
provided to the winding. At least one of these pulses is conduction angle
controlled and adjustable as a function of the latter-mentioned voltage
amplitude so that the total amount of kinetic energy which is supplied to
the armature during movement thereof as the result of the electrical
voltage pulses is substantially equal to the predetermined minimum amount
of energy described previously.
In another embodiment of the invention another voltage pulse is applied to
the electromagnet means at a later time but before said armature abuts
said fixed magnet wherein continued movment of the armature means to the
disposition of abutment by a mid-flight correction adjustment occurs.
In still another embodiment of the invention an electrical contactor or
controller is taught having a movable armature means and a fixed armature
means. An electromagnetic coil means is provided to cause said movable
armature means to abut said fixed armature means. A control means is
provided for supplying the electrical voltage pulse to the electromagnetic
coil means at about the time of abutment to prevent "bounce" if any.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the invention, reference may be had to the
preferred embodiments thereof, shown in the accompanying drawings in
which:
FIG. 1 shows an isometric view of an electromagnetic contactor embodying
teachings of the present invention;
FIG. 2 shows a cutaway elevation of the contactor of FIG. 1 at section
II--II thereof;
FIG. 3 shows force and armature velocity curves for a prior art contactor
with electromagnetic armature accelerating coil, kickout spring and
contact spring;
FIG. 4 shows a set of curves similar to those shown in FIG. 3 but for one
embodiment of the present invention;
FIG. 5 shows a set of curves similar to those shown in FIG. 3 and FIG. 4
but for another embodiment of the invention;
FIG. 6 shows still another set of curves for the apparatus of FIGS. 4 and 5
for voltage and current waveshapes;
FIGS. 7A through 7D show a schematic circuit diagram partially in block
diagram form for an electrical control system for the contactor of FIGS. 1
and 2;
FIG. 8 shows a plan view of a printed circuit board which includes the
circuit elements of FIG. 7 as well as the contactor coil, current
transducers and voltage transformers of FIG. 2;
FIG. 9 shows an elevation of the circuit board of FIG. 8;
FIG. 10 shows the circuit board of FIGS. 8 and 9 in isometric view in a
disposition for mounting in the contactor of FIG. 2;
FIG. 11 shows a circuit diagram and wiring schematic partially in block
diagram form for the contactor of FIGS. 1 and 7 as utilized in conjunction
with a motor controlled thereby;
FIG. 12 shows a schematic arrangement of a current-to-voltage transducer
for utilization in an embodiment of the present invention;
FIG. 13 shows a schematic arrangement of the trnasformer of FIG. 12 with an
integrator circuit;
FIG. 14 shows a plot of air gap length versus the voltage-to-current ratio
for the transducer arrangements of FIGS. 12 and 13;
FIG. 15 shows an embodiment of a current-to-voltage transducer utilizing a
magnetic shim;
FIG. 16 shows an embodiment of a current-to-voltage transducer using an
adjustable protrusion member;
FIG. 17 shows an embodiment of a current-to-voltage transducer utilizing a
movable core portion;
FIG. 18 shows an embodiment of a current-to-voltage transducer utilizing a
powdered metal core;
FIG. 19 shows an algorithm, READSWITCHES, in block diagram form for
utilization by a mircoprocessor for reading switches and discharging
capacitors for the input circuitry of the coil control board of FIG. 7;
FIG. 20 shows an algorithm, READVOLTS, in block diagram form for reading
line voltage for the coil control board of FIG. 7;
FIG. 21 shows an algorith, CHOLD, in block diagram form for reading the
coil current for the coil control circuit of FIG. 7;
FIG. 22 shows an algorithm, RANGE, in block diagram form for reading line
current as determined by the overload relay board of FIG. 7;
FIG. 23 shows a schematic representation of an A-to-D converter and storage
locations associated with determining line current as found in the
microprocessor of the coil control board of the present invention;
FIG. 24 shows an algorithm, FIRE TRIAC, in block diagram form for
utilization by a microprocessor for firing the coil controlling triac for
the coil control board of FIG. 7;
FIG. 25A shows a plot of the derivatives of the line current shown in FIGS.
25A;
FIG. 25B shows a plot of a one-half per unit, a one per unit and a two per
unit sinusoidal representation of a line current for the apparatus
controlled by the present invention;
FIG. 25C shows a plot of resultant analog-to-digital converter input
voltage versus half-cycle sampling intervals (time) for three examples of
line current magnitude of FIG. 25A;
FIG. 26 shows a representation of the binary numbers stored in storage
locations in the microprocessor of FIG. 23 for Example 1 of an
analog-to-digital conversion for six sampling times in the RANGE sampling
routine of FIG. 22 for the one-half per unit line cycle;
FIG. 27 shows a representation of the binary numbers stored in storage
locations in the microprocessor of FIG. 23 for Example 2 of an
analog-to-digital conversion for six sampling times in the RANGE sampling
routine of FIG. 22 for the one per unit line cycle;
FIG. 28 shows a representation of the binary numbers stored in storage
locations in the microprocessor of FIG. 23 for Example 3 of an
analog-to-digital conversion for six sampling times in the RANGE sampling
routine of FIG. 22 for the two per unit line cycle;
FIG. 29 shows plots of VLINE, VRUN(T), and VRUN(F) at the input of the
microprocessor;
FIG. 30 shows a plan view of a printed circuit board similar to that shown
in FIGS. 8 and 9 for utilization in another embodiment of the invention;
FIG. 31 shows a cut-away elevation of a contactor similar to that shown in
FIGS. 1 and 2 for another embodiment of the invention; and
FIG. 32 shows a sectional view of the contactor of FIG. 31 along the
section lines XXXII--XXXII.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIGS. 1 and 2, a three phase electrical contactor or
controller 10 is shown. For the purpose of simplicity of illustration the
construction features of only one of the three poles will be described it
being understood that the other two poles are the same. Contactor 10
comprises a housing 12 made of suitable electrical insulating material
such as glass/nylon composition upon which are disposed electrical load
terminals 14 and 16 for interconnection with an electrical apparatus, a
circuit or a system to be serviced or controlled by the contactor 10. Such
a system is shown schematically in FIG. 11, for example. Terminals 14 and
16 may each form part of a set of three phase electrical terminals as
mentioned previously. Terminals 14 and 16 are spaced apart and
interconnected internally with conductors 20 and 24, respectively, which
extend into the central region of the housing 12. There, conductors 20 and
24 are terminated by appropriate fixed contacts 22 and 26, respectively.
Interconnection of contacts 22 and 26 will establish circuit continuity
between terminals 14 and 16 and render the contactor 10 effective for
conducting electrical current therethrough. A separately manufactured coil
control board 28 (as shown hereinafter in FIGS. 8, 9 and 10) may be
securely disposed within housing 12 in a manner to be described
hereinafter. Disposed on the coil control board 28 is a coil or solenoid
assembly 30 which may include an electrical coil or solenoid 31 disposed
as part thereof. Spaced away from the coil control board 28 and forming
one end of the coil assembly 30 is a spring seat 32 upon which is securely
disposed one end of a kickout spring 34. The other end of the kickout
spring 32 resides against portion 12A of base 12 until movement of carrier
42 in a manner to be described hereinafter causes bottom portion 42a
thereof to pick up spring 34 and compress it against seat 32. This occurs
in a plane outside of the plane of FIG. 2. Spring 34 encircles armature
40. It is picked up by bottom portion 42A where they intersect. The
dimension of member 42 into the plane of FIG. 2 is larger than the
diameter of the spring 34. A fixed magnet or slug of magnetizable material
36 is strategically disposed within a channel 38 radially aligned with the
solenoid or coil 31 of the coil assembly 30. Axially displaced from the
fixed magnet 36 and disposed in the same channel 38 is a magnetic armature
or magnetic flux conductive member 40 which is longitudinally (axially)
movable in the channel 38 relative to the fixed magnet 36. At the end of
the armature 40 and spaced away from the fixed magnetic 36 is the
longitudinally extending electrically insulating contact carrier 42 upon
which is disposed an electrically conducting contact bridge 44. On one
radial arm of contact bridge 44 is disposed a contact 46, and on another
radial arm of contact bridge 44 is disposed a contact 48. Of course, it is
to be remembered that the contacts are in triplicate for a 3 pole
contactor. Contact 46 abuts contact 22 (22-4 | | |
