Relay circuit breaker with magnetic latching to provide conductive and nonconductive paths for current device

Reinhold, H. W.

Reynolds, W. E.

English

NASA Technical Reports Server

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REPLY TO 
ATTN OF: G P  
TO P 
FROMt 
SUBJECTr 
NATIONAL AERONAUTiCS AND SPACE ADMINISTRATION 
WASHINGTON. D.C. 20546 
uSI/Scientific 6 Technical Infomatkon 
Attentions M i s e 4  Winnis M. Morgan 
G P / O f f i c e  of AsaiTtaqt General Counsel 
Patent  Matters 
Division 
f o r  
announcement of NASA-Owned U. S. Patents  in STAR 
1x1 accordance w i t h  the procedures agreed upon by Code GP 
and Code USI, .the attached NASA-awned U. S. Patent  is being 
forwarded for  abs t rac t ing  and announcement i n  NASA STAR. 
The following information is provided: 
U. S. Patent  No. 
Government or 
Corporate Employee 
Supplementary Corporate 
Source ( i f  applicable) t 
NASA Patent  C a s e  No. t 
NOTE - I f  th i s  pa ten t  covers an invention made by a corporate 
employee of a NASA Contra torr  the following is applicablet 
Pursuant t o  Sect ion 305 (a of the National Aeronautics and 
Space A c t ,  the name of the Administrator of NASA appears on 
the first page of the patent ;  however, the name of the ac tua l  
inventor  (author) appears a t  the heading of Column No, 1 of 
the Specif icat ion,  following the words with respect to 
Y e s  E? No 0 
https://ntrs.nasa.gov/search.jsp?R=19710019532 2020-03-17T03:11:07+00:00Z
nited States Patent 
[ 721 Inventors T. 0. Paine 
Acting AdminiStrator of the National 
Aeronautics and Space Administration with 
respect to an invention of; 
Williard E. Reynolds, Plymouth, Mich.; 
Henry W. Reinhold 
[21] Appl. No. 771,759 
1221 Filed Oct.30,1%8 
[45] Patented May 18,1971 
[ 541 CIRCUIT BREAKER UTILIZING MAGNETIC 
LATCHMG RELAYS 
3 Claims, 1 Drawing Fig. 
I521 U S .  c1 .................................................... ;... 317/33, 
3 17154.3 17/60,3 171155.5 
[51] Int.CI. ........................................................ H02h 3/08 
[50] Field of Search ............................................ 317/33,, 
155.5,54,60 
[ I * ]  3,579,041 
[561 References Cited 
UNlTED STATES PATENTS 
2,925.536 211960 Stineman ...................... 317154 
3,317,793 5/1967 Peek et al ..................... 317/33(X) 
3,333,155 7/1967: Steen ............................ 317/33(X) 
Primon! Examiner-J. D. Miller 
Assistant E.wrniner-Harvey Fendelman 
Attorneys-Marvin F. Matthews, Marvin J. Mamock and G. T. 
McCoy 
ABSTRAGT: In circuit breakers wherein power consumption 
is significant, a circuit breaker relay being operably controlled 
by switching transistors normally biased off, the operation of 
which is triggered by a magnetic latching relay having a coil 
sensitive to current flow and requiring current flow only on 
switching. 
ay 18, 1971 
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I. Willard E. Reynolds 
Henry W Reinhold I__ 
BY 
ATTORNEYS 
3,579,04 1 
1 a 
U T  ~ ~ ~ E R  UTILIZING MAGNETIC LATCHING 32, on operation, switches the armature to the relay contact 
RELAYS 35. Since other details of the relay 36) are quite similar to those 
The invention described herein was made in the per- of the relay 20, it is believed unnecessary to further elaborate 
formance of work under a NASA Contract and is subject to on the construction thereof. 
the provisions Of section 305 of the National Aeronautics and 5 The conductor 11 is communicated with a conductor 46) 
Space a c t  Of 19% Public Law 85-568 (72 Stat. 435; 42 which is connccted to the coil 22 and then to the collector of a 
U.S.C. 2457. transistor 41. An appropriately connected diode 411 42 
Relay circuit b ~ a k e r s  are normally designed to Prevent prevents damaging peak voltage surges in the coil 22. The 
overload Of power sources 01' other operative conditions emitter of the transistor 41 is grounded while the base is pro- 
which exceed predetermined tolerances. For instance, loss of 10 vided with a signal through = series dropping resistor 43 from 
line voltage is a sufficient reason for operating circuit breakers the collector of an transistor 44. The transistor 44 is 
in some circumstances. Excessive current demands are a p ~ p  transistor having its emitter connected with a 5-volt 
likewise considered to be a problem, and circuit source at 45. Of course, other suitable small voltages are easily 
breakers are likewise protective apinst such events. The aP- adaptable depending on the specific transistor selected. The 
paratus of the present invention is summarized as including a 15 transistors 41 4 are switching transistors with the 
current switching main relay which is magnetically latched to transistor 44 controlling operation of the transistor 41. on ap- 
for the current device. The apparatus further incoPOMtes a explained hereinafter, the transistor 41 is rendered conduc- 
provides control signals for switching transistorswhich control 
the power the transistors being biased normal'y Off so 
that the total power consumption of the entirety of the circuit 
coil. 
Provide a conductive and IKmconductive path therethrough 
ma@etic latching 
rents and 
plication of an appropriate signal to the transistor Qa as will be 
which is responsive to Overload cur- 2o tive, thereby effectively grounding one end of the coil 22. A 
pulse of current through the coil 22 switches the armature 23 sensing Operations The second relay 
to the relay contact 24, the position being maintained even 
after lapse of the current pulse until the relay coil 21 is ener- 
gized. 
ductive position whereby current is communicated from the 
power source at 111 to the load connected to the conductor 12. 
then connected to the coil 32. The coil 32 is a relatively low 
To prevent the possibility of a heavy overload burning open 
limited to the power consumPtion Of the sensing 25 Movement of the armature 23 to the terminal 25 is the con- 
Many Objects and Of the present invention will 
Inore apparent from a consideration Of the The 25 is communicated with a conductor 46 which is below included specification and single drawing, wherein. 
tion is shown in the single figure of the drawing. 
A circuit d & ~ m  of the relay circuit breaker of this inven- 3o resistance coil for low voltage drop and low power dissipation, 
Referring more ~rt icular lY to the single drawing the cir- 
cuitv indicated by the numeral ' comprises the improved coil 32, a diode 47 is provided in parallel so that cur- rent is shunted around the coil 32. The diode 47 is preferably a relay circuit breaker of the present invention. The numeral I 1  
indicates a conductor communicating with a suitable power 35 around the coil 32. The resistor 48 is 
source of any description. The numeral 12 indicates a conduc- 
tor communicating with load, the nature of which is not sig- 
nificant for purposes of the present invention The current 
flows from the conductor 12 of the 
present circuitry, and so long as alarm conditions are absent, 
the 
for remote control and switching of the relay circuit breaker 
which supply, respec- 
tively, off and on commands to the apparatus. 
heavy duty diode capable of conducting a short circuit current 
to set the 
breaker 10 overload trip current to the desired value. 
The foregoing traces out the flow path of current in 
quiescent conditions. However, to complete the description 
thereof, it should be noted that the relay contact 24 of the 
is uninterrupted. Additionally, provisions are made 40 relay 20 directs the source current through a diode 49 and 
then to the coil 31. The coil 31 is protected against voltage 
surges by a diode 58. While the schematic including the coil 
31 appears incomplete, the schematic representation is in- 
45 tended to describe the coil 31 in connection for sensing of the 
is input to a switching normal voltage of the source connected to the wire 11. Thus, 
relay indicated by the numeral u). me relay is enclosed those skilled in the art will appreciate the use and function of 
the dotted line shown in the drawing, which is included to the 'Oil 31 in the present invention. 
that the components thereof are suitably encased in a The armature 23 is contacted against the terminal 25 on 
we&known structure which need not be further illustrated. 5o operation of the coil 21. The coil 21 is protected by an addi- 
ne relay U) is ofthe magnetic latching variety as to tional diode 51 in similar in function to the other diodes in 
he  convention^ relay operated by a solenoid on one side of protection of the relay coils. The coil 21 is connected in series 
the contact against a spring on the opposite with the transistor 52. The transistor is grounded through its 
Side of the tn the present device, and as illustrated, emitter as is the switching transistor 41 and operates in the 
the relay 20 incorporates a coil 21 and a second coil 22. m e  55 Same manner as the transistor 41. 
illustrated is a result of operation of the coil 22. It will Control signals for the switching transistor 52 are applied 
bt the coils 21 and 22 work against one through a base resistor 54 which is derived from an additional 
another in moving the armature 23. me armature w is moved switching transistor 55. The transistor 55 derives its current 
between relay con&& 24 and 25, the relay Contact 25 being flow from the low voltage Positive source 45 PrevioUSb 
energ* when breaker 10 is operative. It will bt: un- 60 described. The transistor 55 is normally biased off but is 
d e r s a  that coils are by passing a pulse switched on by a signal applied to the base through a resistor 
therethrough, a pulse which n& not be sustained to maintain 56 which is connected to the on command conductor 14 
the armatwe 23 in the switched position corresponding to the which provides remote control capabilities for the present cir- 
selected energized coil. cuit breaker. At this juncture it should be noted that the con- 
A sellsing relay 39 is like& illustrated in the single draw- 65 ductor 13 which provides the off command communicates 
bg. n e  relay 30 is quite in c o m t i o n  to the relay through the relay 38 in the illustrated position of the relay to a 
B, is characterized as being a magnetic latching relay resistor 57 which is input to the base of the transistor 
having an armatuce which is moved to a position by one of two transistors 44 and 55 are similar in function and operation of 
coils, a pulse of current through either coil being sufficient to the switching transistors 41 and 52, respectively. 
switch the armature to maintain the armature at that posi- 70 Considering operation of the present invention, the 
tion even after the current has passes until either of the coils is quiescent operative condition is achieved wherein the arma- 
next again energized. For identification, the relay 30 includes ture 23 is switched to the relay contact 25. This provides the 
a voltage sensitive coil 31 and a current sensitive coil 32. The needed current flow through the conductor 46 to the low im- 
armature is indicated by the numeral 33. The armature is pedance combination of the diode 47, the resistor 48 and the 
switched by the coil 31 to the relay contact 34 while thc coil 75 coil 32 to the load at the conductor 12. This operative condi- 
to the 
through the conductors 13 and 
Considering the invention in detail, the conductor 
with the power 
3 S 79.04 1 
3 4 
lion is maintained indefinitely until the current is considered 
excessive. The apparatus of the present invention is preferably 
calibrated so than the number of turns in the coil 32, the wire 
gauge and other parameters of the relay and the value of the 
resistor 48 governs the triggering point of the circuit breaker 
apparatus 18. Thus, it can be set to trip at selected high or in- 
$ermediate current levels as the need may arise. Without re- 
gard to the current setting, the coil 32 i s  sensitive to current 
flow in excess of the established level considered safe, and 
consequendy, when this level is exceeded, the relay 32 
switches the armature 33 to the terminal 35. The terminal 35 
provides a ground connection through the resistor 57 to the 
base of the switching transistor 44. In quiescent conditions, 
the transistor 44 is biased off however, on application of 
ground to the base, current flows in the collector circuitry. 
The current flow in the collector circuitry provides a positive 
pulse at the base of the transistor 41. The positive pulse 
senders the transistor conductive and current flows through 
the conductor 40 and the coil 22. Such current flows operates 
the relay 28 in the manner described hereinbefore. 
By way of contrast, consider operation of the relay coil 21. 
ake conductors 13 and 14 are preferably communicated with 
the same voltage level as that provided on the conductor 45.5 
volts DC as described in this preferred embodiment. On appli- 
cation of approximately ground potential on the conductor 14 
through the resistor 56, the transistor 55 is biased from off to 
an on and conducts heavily. Current flow in the collector 52 
on. The transistor 52 conducts heavily and the current flow 
through the coil 211 is established from the power flow source 
at 11 through the coil 21, the transistor 52 and to ground. 
Thus, the coil 21 switches the relay 20 in the manner 
described hereinbefore. 
As will be appreciated from the foregoing, one of the major 
objects of the present invention has been described in opera- 
tion wherein the switching transistors are normally biased off 
and only conduct when the operative state of the circuit 
breaker 10 is altered. Thus in quiescent operative conditions, 
the present apparatus consumes practically no power with the 
exception of the slight power losses in the parallel combina- 
tion of the coil 32 and diode 47 and shunt resistor 48. This is 
of significant benefit in that the shunt resistor 
nificant benefit in that the inefficiencies of a power consuming 
circuit breaker are avoided in installations in which power 
consumption is critical. Moreover, the apparatus provided is 
essentially free of stress and fatigue factors as the equipment 
ages. Typically in spring operated or bimetallic equipment, 
aging and fatigue factors become significant. However, the 
present invention avoids such problems and further is essen- 
tially free of thermal problems during its operation over an ex- 
tended period of time. 
While the foregoing has described the circuit bre&er with 
specified voltages, polarities and specific interconnections, 
the present teaching includes other arrangements. For in- 
stance, the various relay coils of the sensing relay may be 
responsive to timed power outage, fast occurring peaks of cur- 
rent flow, slow occuring peaks of current flow, and the like. 
More particularly, the circuit breaker may be extended to 
three phase protection wherein loss of a single phase operates 
the apparatus. FurtRer, the preferred embodiment presup 
posed use of a positive supply; the use of a negative supply 
voltage creates no particular problem. Of particular interest is 
the provision of a circuit breaker consuming a minimum of 
power in the sensing coil, and using transistors normally 
biased off to thereby provide a circuit breaker which con- 
serves power in operation. 
While the foregoing has been directed to the preferred em- 
5 bodiment, the scope of the present invention is determined by 
the claims appended hereto. 
We claim: 
I. Circuit breaker apparatus providing overload protection 
while consuming negligible power during quiescent operating 
a. a power contr4 relay having connections for inter- 
ruptably transferring electrical power from a power 
source to a power consuming load; 
b. sensor means responsive to the power consumption of the 
load for forming a control signal supplied to said power 
control relay to interrupt power flow to the load in 
response to overload conditions; 
c. means for operating said power control relay in response 
to the control signal from said sensor means, said means 
having a quiescent condition in which said means are 
biased to consume no power, said means consuming 
power in response to the control signal and thereafter ter- 
minating power consumption after operation of said 
power control relay to interrupt power flow to the load: 
d. said power control relay comprising a magnetic latching 
relay having a first and second coil therein, said coils each 
operating said relay to a selected position; 
e. first and second switching transistor means connected to 
each of said coils for controlling current flow 
f. said rehy maintaining an operative position achieved 
after flowing current through either of said coils, said 
position being maintained without further current flow 
for an indefinite period of time. 
2. The invention of claim 1 wherein 
a. said power control relay includes a first magnetic latching 
relay; 
b. a second magnetic latching relay included in said sensor 
means, 
c. said transistor means being normally nonconductive and 
connected to said first relay for operating same to inter- 
rupt power flow therethrough; and, 
d. said sensor means incorporating said second relay and 
operating same on overload, said second relay being con- 
nected to said transistor means, and supplying a a pulse 
thereto for causing conduction by said transistor means to 
operate said first relay. 
10 conditions, comprisirm : 
15 
20 
25 
30 therethrough; and, 
35 
40 
45 
3. The invention of claim 1 wherein 
a. said power control relay includes a first magnetic latching 
b. a second magnetic latching relay included in said sensor 
means, 
c. said transistor means being normally nonconductive and 
connected to said first relay for operating same to inter- 
d. a coil in said second relay sensitive to excessive current 
flow from the source to the bad, said coil changing the 
operative condition of said second relay and, 
e. there being connections cooperative with the contacts of 
said second relay for forming a conductive signal; and, 
f. connective means for supplying the conductive signal to 
said transistor means. 
50 relay; 
55 rupt power flow therethrough; 
60 
65 
70 
75 


Circuit breaker utilizing magnetic latching relays Patent

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