US2014049A - Light signaling circuit - Google Patents

Description

Sept. l0, 1935. i K MEYER 2,014,049 l LIGHT SIGNALING .CIRCUIT l l Filed Jan. 29, 1932 Figa 1. 3.

.` I I A ASnnentor Blijf 2, bn'ngggf Cttorneg Patented Sept. 10, 1935' l l UNITED STATES LIGHT SIGNALING CIRCUIT Karl Meyer, Berlin-Charlottenburg, Germany,

assigner to Orenstein & Koppel Aktiengesellschaft, Berlin, Germany Application January 29, 1932, Serial No. 589,695 t In Germany May 12, 1931 3Claims.

My former U. S. application led April 13, 1931, Serial No. 529,770 describes a iight signaling system wherein the change of signals takes place semi-automatically by using a polyphase 5 network. During the iiow of the clear current,

the stop lamp is extinguished by an electromotive force which is induced in a reactance and is practically equal to and practically oppositely dlrected to the stop light phase voltage in the phase position. Consequently, in the case of a closed clear current branch, only a smallfraction of the clear current ilows in the stop current branch so that the stop lamp is absolutely dark when the clear lamp lights up. If, however, the

clear circuit is broken by a switch in the clear lamp circuit or by a defect such as the burning out of the clear lamp, the electromotive force, which hitherto acted against the stop lamp current, is eliminated and, therefore, the stop lamp will light up with full strength as soon as the clear lamp is extinguished.

According to the present invention, the same eiect is obtained by using a single phase alternating current. It is also possible in these systems to devise the arrangement in such a. manner that in the closed clear lamp circuit, the stop lamp receives a weakened current so that the lamp does not light up while after the clear lamp circuit is broken, the stop lamp receives its full current and, therefore, lights up with normal strength. l

According to the same principle, an emergency stop lamp connected in parallel to the stop lamp can be brought into reciprocal action with the main stop lamp so that when the main stop lamp is extinguished, in consequence of a disturbance, 'a's i'or instance, when it burns out, the emergency stop lamp lights up, and vice versa.

Three constructional forms of the invention are shown in the accompanying drawing by way of example:

Figure 1 shows vthe system with a clear lamp F and a stop lamp H; y

Figure 2 shows the system according to Figure 1 but with an emergency stop lamp HN connected in parallel to the stop lamp H; Y Figure 3 shows a system similar to Figurer 2 but with a different arrangement of the condensers and choke coils;

Figure 4 is a vector diagram for representing the voltages of the currents.

Referring to the drawing `in detail, a circuit extends from a pole R of a *single phase network Rf-S to a choke coil D, Figure 1, and branches behind the latter into two parallel cenductors (cl. 1v1- 329) I f which are connected to' the other pole S of the network. One of these branches which may be called the clear lamp branch, contains in series connection the clear lamp F, a switch s and a fuse, while the other branch contains the stop 5 lamp H, condenser C and a fuse.

In Figures 1 and 4 Xc is the capacity reactance of the condenser C; l

XD the inductive reactance of the choke coil D; 10

Rn the ohmic resistance of the stop lamp;

RF the ohmic resistance of the clear lamp;

J the total current in the circuit Aextending from the pole R;

Z the so-called impedance of the whole circuit, 15 i. e. that ohmic resistance which per se would give the same current J with the network voltage Ea-s.

The capacity reactance Xo is a multiple higher than the ohmic resistance RH of the stop lamp, 20 i. e.,

Furthermore, one selects:

-XCZXD ohms l 25 For the stop lamp branch, there results an impedance J .RF-indicates the effective voltage EF on/the 50 clear lamp. It is to be noted that, as already stated, the total current J is practically equal to the current JF flowing through .the clear lamp branch. The constitution of the network voltage is shown in -the vector diagram of Figure 4; the f' vectors Er=JrJtr andl .Ii-.Xn which are Joined at right angles yield the total voltage Jr.Z=En-s; in the vector diagram the index H at R is omitted and the index D at X is omitted so that the di'agram also applies to further cases.

It will be seen that in the case of an illuminated clear lamp, a voltage of self induction is produced by the clear lamp current Jr which voltage is compod of the effective voltage components JrR so that a practically appreciable voltage and current component for the branch of the stop lamp does not remain.

The phase angle ar between the network voltage Ea-s and the enective .voltage Jr.R is determined according to Figure 4 from co. because the total impedance Z is practically equal to Xn.

Furthermore, when selecting the electric values of the choke coll D and the condenser C so `that in the case of the closed clear lamp circuit the impedance Z is equal according to its absolute value to the impedance Xn-i-Xc when the clear lamp circuit is open, the phase angle on between the current Jn and the network voltage ER-s is determined from the equation Since according to the above assumption Xc= -2Xnthe denominator of the fraction win pe Xn+Xc=Xn and therefore C08 i wa- XD that is to say, according tothe above assumption in other words, the angles r and 4m are equal as shown in Figure 4. It may be desirable to give a numerical example for the selection of all electrical values as follows:

The clear lamp F and the stop lamp H have each a power of 60 watts with a voltage of 120 volts, the current being 0.5 ampere and the resistance 240v ohms. Y

The reactance of the choke coil D in the common branch circuit amounts to LD' =1.5 henry at 50 Hertzl ==3.3 micro-tarado Consequently, the voltage of the network must amount to Eg5=J4R+ XD2= (15x/240271F 4802= 265 volts The residualcurrent over the stop lamp Hv with closedl clear lamp branch circuit therefore results m 120 'd 1= 0.1 22 Jg resi ua J24402+9602 amp This is about 24% of the rate current, that is to say the stop lamp remains dark.

However, when the clear lamp branch circuit is open, a current flows over the stop lamp, which current is as high as, in the former case the current J for the clear lamp, so that now the stop lamp will fully light up.

The invention may also be realized by using a condenser instead of the choke coil and a choke coil instead -of the condenser. Such an exchange is obvious when comparing Fig. 2 and Fig. 3 with one another.

The use of an emergency stop lamp HN is also obvious from these two figures, which lamp, with regard to arrangement and effect, bears the same relationship to the main stop lamp H as the latter to the clear lamp F.

According to Figure 2, a choke coil D1 is located in the circuit coming from the network conductor R; behind the said coil, the circuitl is branched into two conductors, the first one, namely, the clear 'lamp branch corresponding with the clear lamp branch of Figure 1. second branch contains a condenser C behind which extends the branch of the main stop lamp H over a fuse to the network conductor S. The

=0.5 amp.

Dz, the emergency stop lamp HN and a fuse extends parallel to the main stop lamp H from behind the condenser C to the network conductor S.

The operation is asfollows:

When the switch s is closed, the clear lamp F lights up and produces in the choke coil D1 such a voltage of self-induction directed against the network voltage that the voltage for the main lamp branch and especially the voltage for the emergency lamp branch is not suilicient for producing a current sufllcient for lighting up the main stop lamp H or even the emergency stop lamp HN, these two lamps being extinguished.

If the switch s is now opened o r the clear lamp branch interrupted, the counter-voltage in the choke coil D1 coming from the clear lamp current according to Figure 1 will disappear again.

The capacity resistance of the condenser C is again greater than the inductive resistance of Athe choke coil D1; a counter-voltage directed against the network voltage will be produced in the choke coil Di and in the condenser C by the current passing over the main stop lamp H against the network voltage and the voltage for the emergency stop lamp EN behind the choke coil D2 is not suflicient for lighting up the emer-v gency stop lamp. The emergency stop lamp HN receives a current suflicient for the lighting up only when in the case of an interruption of the clear current branch, the branch of the stop lamp H (by burning out) is also interrupted; the sum of the resistances in the choke coils Di and D: and also in the condenser C may be such that the absolute value of the apparent resistance is` the same as in the case of the lighted clear lamp F orlighted main stop lamp H.

A numerical example will also be given for Fig. 2. It is assumed that all three lamps F, H and HN are adapted for the same rated current and the same rated voltage .this is not absolutely necessary; more favorable values are obtainable by feeding each lamp over a transformer in which case the same voltage values are not necessary. It must be borne in mind that the assumed numerical values as welllas the assumed proportional values of the reactances are nothing more than mere examples.

The calculation is based on the following symbols one part of which is defined above: y

Ens=network voltage of the single phase network R-S;

E'=rated voltage of the individual lamps F, H or HN;

Er=voltage for the clear lamp;

En=voltage for the stop lamp;

Eau=vo1tage for the emergency stop lamp;

J '=rated current of each of the three lamps F, H or HN;

EHN=0.242 J'.RHN Volts NHN=0.058 J '2.RHN Watts (3) Clear current branch and stop current brunch l interrupted Ra=RrrlRHN EH=EF=EHN -Xc=2Xm=Xm=4RH there will be for (1) Closed clear current branch I Ex-s=] =-Jm=flr=5rnl` (a) In the clear current branch:

Er=E' volts Jr=J amp.

. Nr--N' watts (b) In the stop current branch:

JFLJLRL:

Z JXC2+RH2 Rua/ EH=0.242 J'.RH

NH=0.058 J". RH (c) In the emergency current branch:

EHN=0.058 J .RHN VOlts NHN=0.0033 J".Rmv watts (2) Clear current branch open, main stop lamp intact v Ln1=2 f y. (a) Er=0 JF=0 Nr=0 (b) EH=0 JH=0 NH=0 (c) EH=E' volts JH=J amp. NH=N watts Assuming N'=60 watts E=120 volts l "J'=0.5 amp. f

RH= RF=RHN=240 ohms there results for the choke coil D1r XD1=2RH=2240=480 ohms or the inductance For the condenser C:

XC=4RH=4240=960 ohms or the capacity For the network voltage:

E 8=E,.1/'5=12o.1/5=265 vom The individual value for the cases (l), (2)

=l.51 hem-ies with 50 Hertz l C =3.3 mcrofaradl (1) a. Er=120 volts Js=0.5 amp. Nr= watts JH=,0.121 amp. EH=29 volts NH=3.5 watts c. JHN=0.029 amp.

EHN=6.95 volts N11N=0.2 Watts h. Ju=0.5 amp.

EH=120 volts NH=60 watts JH`N=0.121 amp EHN=29 volts Nmv=3.5 watts (3) a. Jr=0 amp. ot one lamp', a condenser or a choke coil in the I b. Jn==0 amp. branch ot the other lamp, and a choke coil or c. Jmv=0.5 amp. 'a condenser. respectively. common to both Enn=l20 volts branches, having at most halt the value of the Nmv=80 watts condenser or choke coil, respectively, in the one 5 The arrangement according to Figure 3 has been derived from that according to Figure 2 by replacing the condenser C by a choke coll D and 'replacing the choke coils D1 and D: by condensers Ci Cs.

It has been proved by means of Pigure 2 that the condenser C which is connected in iront of the branches for the stoplamp H and for the emergency stop lamp HN is adapted to act together with the choke coil Dz of the emergency stop lamp branch in the same manner as was proved in connection with the clear lamp branch for a case where vice versa the means connected in front wasachokecollDiandthemeanslocatedinone' branch was a condenser C. It follows therefrom that the exchange made in Figure 3 also constitutes an eilective arrangement in accordance with the invention.

What I claim is:

1. A light signaling system for single phase alternating current with successive illumination otlampsotdinerentcharactercomprisingecurrent supply circuit, lamps connected in'parallel branehesofsaiclcircuit.switchinthebrunchl a. switch in the other parallel circuit for disconnecting the clear lump circuit and 'thereby rendering operative the stop lamp, and vice-versa. ondasubstitute stoplamp and achoking coil in series with one another connected in parallel 20 with the main stopl lamp,. this choking coil havina at least hal! the valueot the said condenser. so that the substitute stop lamp will light up automatically when neither the clear lamp nos' the moin stop lamp is in operation.

3. light signaling systemes per c1aim2, thev said condenser being substituted by a choke coil. and the said choke coils being substituted by con- KARLMEYER. I0

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