US2303786A - Electrical system and method - Google Patents

Description

J. l.. BONANNO ELECTRICAL SYSTEM AND METHOD Filed May 24, 1941 WN MN Avsk Q INVENTOR JasfP/f 30A/mwa B5 ATTORNEY Patented nee 1, 1942' UNITED STATES PAT-ENT oFF-ics ELECTRICAL i YSTEM AND METHOD Joleph L. Bonanno, MaplewomL'N. J., Win01' to I The Lionel Corporation, New York. N. Y., s. corporation of New York application Mayzi. 1941, N c. 395,90; 'in claims (ci. m-is'oif v I substantially the same voltage'isapplied to the The present invention relates to electrical systems and methods; and is more particularly'dilrected toward 'electrical systems andmethods suitable for' use inthe operation of toy electric railroad outiits by rectified direct current.

Owing t'o the more general availability of itl-- ternating current in house lighting. toy electric trains and accessories have been developed for -operationzon 'alternating currentcircuits. 'To obtain directional control of the trains it has been customary `to employ a reversing switch Voperated by a relay on lthe locomotive responsive :to successive impulses-of current so that obtaining true directional control oi' the required the luse'oi moving parts. as .well as the operation of the impulse sending switch. This switch had to be manipulated the desired 4num- A ber of times to-secure'operation the direction In toy train voperation the whistle usually been operated by an alternating current motor under the controlof a relay responsive only to trlcal system and method according-to-which ruperposed direct current. A similar-circuit is used for control of electromagnetically operated couplers..

'Ihe present invention contemplates an electhe alternating current is passed through a full v wave :causer and the output or uns rectifier .u

consisting of direct current with admixed or superposed alternating current of double frequency (usually 120 cycles) is supplied to the toy track l magnet. l

According to the present invention thesecond current consuming device (such as the whistle motor or coil of the coupler) isl direct current operable, nonpolarized`and .under-the Vcontrol of a relay normally held open by` alternating cin-rent normally flowing from the rectifier, and

sintahie'means are provided whereby the alteralternating current frequency is completely iiltered out and eliminated, but according to thel natingcurrent output' of the rectifier maybe l iiltered out of the'track circuit, or reduced to a sumc'ient amount, to permit the relay to release its contacts so that the second current consuming device may be ope1's.ted.`- s

The operation oi' the second motor, or whistle,

at the same time 'that the main or' propulsion motor is operating causes a sustained-increased load onthe circuit which in usual'practice has limited output and relatively poor regulation,

and according to the present invention the whistie controller ls preferably of such design as to substantially increase the available direct current voltage for operating this motor so that locomotive motor, irrespective of whether'the whistle is, or is'not. operated.

The 'accompanying drawingshows,4 for 'purposes` of illustrating the present invention, one ofthe many embodiments in which the invention may take form, together -with modifications of certainparts, it being understood that the drawing is illustrative oi the invention rather than limiting the same.

Inthedrawing:

'Figure 1 lis a complete wiring diagram for an alternating current to direct current Power supply for the track circuito: a toy railroad outit having a polarized motor;

'Figure 2 is adiagrammatic view illustrating .the action of die lfull wave rectifier in providing direct current potential and superposed al- 'ternating currentpotential o! double the supply .frequenm- Figure 3-is airagmentary view a modined form of reversible motor:

Figure '4 is-a diagrammatic view illustrating various'ltering circuits which may be employed;

Figure 5 is a diagram illustrating the alternoting current performances of the circuitsot Figure-4;

-Figure 6 is a wiring diagram of the preferred form of ltering circuit as set up for atest of alternatingourrent and direct current perform ance; and

Figure 'l is a diagram illustrating the direct current and alternating current perfomance of the circuit or Figure 6.

In Figure 1 a variable voltage output trans,

former, indicated at'T, is connected with afull y wave-rectier R, preferably of the copper oxide type. Thisrectifier,l as shown in Figure 2, is

= adapted to converti; supply voltage, indicated by the sine curve I I, into a direct current potential, indicatedv by the horizontal-line ii, and ari-alternating current "ripple voltage, indicated by the curve fil, of twice the frequency of the supply current It. In the more ordinary 4uses of rectiflers'for providing direct current this present invention this double frequency alterhating current is employed for control purposes. The output terminals i3 and il of the tull wave rectiiier R. are connected tothe movable contacts" i5 and II of a'.- reversing switch il. 'Rus connection is preferably made throughs. choke coil i8 adapted to be shunted by a switch il.

The track load has a locomotive propulsion motor 22, which 'is here shown as of the split L The coil 2l of the whistle relay is connected through a condenser 28 with the track circuit so that alternating current may flow through the whistle relay coil, the condenser and coilbeing preferably tuned 'to proper frequency. This tuning increases the sensitivity by lowering the impedance to the current to 120 cycle frequency" and also keeps spurious frequencies generated by commutator sparking from interfering with the operation of the relay. In other words the relay is selectively tuned. The condenser 28 prevents any direct current from iiowing through the relaycoil. .'lhe output terminals i3 and Hf of the rectiiier are shunted by a choke coil 30,-

condenser 3| and norm-ally open switch 32, the choke and condenser 4being tuned to theproper frequency.

The parts 24 to 2t are here shown as pennanently connected in parallel with the propulsion motor, but they, or their equivalent, may be temporarily or permanently connected elsewhere in the network so long as they are in parallel'with the iltering circuit when control isdesired.-

When the propulsion motor alone is to be operated it can be started, stopped and reversed by means of the reversing switch I1 and may be supplied with the output ot the rectiiier with the choke i8 in circuit or Without, as desired. For

loads such as the whistle motor, the direct current voltage regulation is better with the choke Il permanently in circuit. The lamps 1B will-be lighted only when the motor is energized.

When the whistle is to be operated the whistle control button 32 is moved to the circuit closing position so that the dominant portion oi the alternating current output of the rectiiier R is by-pcssed through this shunt and does not reach kthe whistle relay, thereby reducing the current in the whistle relay to such an ammmt that it drops its contact to close the circuit for the whistle motor.

Instead of using a propulsion motor with s. split field one could use apropulsion motor ot the usual type shown in Figure 3 with full wave reiitiiicrv 8l.. The principal advantage of this arrangement lies in the tact that the field winding has a higher space factor de to the use ot the -entire space available for the tield winding at all times. This improvement over the split ileld is obtained however at an increased' rectiiier cost, four sets of elements being required instead of two. also be used.

- Figures 4 and 5 illustrate the operation ot an oumut circuit from a full wave rectiner of the copper oxide type wherein alternative forms of nltering means are provided, the alternating current input to the rectiner being 14 volta In this set up two 2,000 mid condensers 35 and I8 are provided to be' connected across the circuit by switches 31 and Il. A condenser 30 of 300 mrd. tuned with a choke u is under the contrer' of a switch BI. A series choke 42 ot .8 ohms A permanent eld .motor may' direct current resistance is adapted to be shunted by a switch 43, a variable resistance load 4I is employed and the current and voltage measured by instruments as indicated 'I'he'results of a series of tests are shown in Figure 5, the curve 50 indicating the results when there is no shunt and no series choke, the curve Il the results when the series choke is unshunted, the curve 52 the results with one condenser 35 only in circuit, the curve 53 the results with the tuned condenser and choke I9, 40 only in circuit, the curve I4 the results with the choke and condenser, 4I and the choke 42 in circuit, the curve l! the results where two condensers ,35v and 36 are in circuit, the curve 5I the results where two condensers 3i and 3l and the choke 42 are in circuit, and the curve Il the results where one condenser V35 and the choke 42 are in circuit.

From Figure 5 it will be apparent that under the particular conditions of the tests several methods are available for reducing or substantially eliminating the alternating current component. The simplest, but not the best, isto use alarge condenser such as illustrated by the curve 55. This is less eil'ective at heavy load, but the cost of the high capacity Acondenser (necessary on'60 cycles) makes this method objectionable. The vtuned circuit Il, Il producing curve. I3 on Figure 5, while not so euective at low current values. is practically as effective at large current values, as the 4.000 mrd. condenser arrangement resulting in curve ll. 'I'his niter arrangement is therefore the one which is shown in Figures 1 and 6.-v

Figures 6 and' illustrate the results obtained by placing a 300 mrd. condenser u and tuning choke 4l across. the rectiiier output terminals, and employing a sexies choke l! with a direct current resistance o! 0.89 ohm. These tests were made with a full wave rectifier of the copper cxide'type provided with s 2l wie alternating current input. lThe direct current, volts are indicated in Figure 7 in heavy lines, the alter' hating current volts are indicated in light lines. These curves are tabulated as follows:

' l Curve- -A. C. volts-no series choke-no shunt nlter A l-m C.v volt|-no series choke-no shunt iilter 62A. C.'voltvwith series chokeuo shunt nlter ori-D. C. volts-with series choke-mo shunt lter (H-A. C. volta-with series choke-with shunt filter (i5-D. C. volts-with series-choko-with shunt dlter (i6-A. C. voith-no series choke--with shunt illtet 67-D. C. volto-uo series chokwith shunt filter Form curves Si and CI ot Figure 7 it vvillbe 18 and 14 volts direct current with a load of from zero to 3 amperes will have present across the load from 8.6 to 5.8 volts, cycle A. C. Any means that will enable the alternating current component to rind a. ready path will improve the action of the rectmer and increase the directiect of introducing the tuned condenser shunt Y Si, i0 across-the line is apparent by comparison of the curves il and 81. At' a load of 1.25 am peresthe direct current voltage rises from l5 volts to 17 volts when the tuned condenser choke shunt is completed. This rise in voltage serves to compensate for the drop in' voltage through the rectiner and transformer when the whistle motor is introduced as a further load.

aaoavsc condenser shunted across the rectifier output As stated above neither the large condenser nor the shunt alone will entirely eliminate the alternating currentI voltage on heavy loads. For example, as shown by curve 66 there ls still 1.9 volts alternating current present across the load with the choke and condenser shunt I9, 40. The curve 6U shows that at the same time there is a normal alternating current voltage of 5.8 volts without the shunt so that there is available a ration of 3 to 1 'in alternating current voltage available for operation of the relay. This ratio can further be improved by placing a series choke in the line to the load which increases the effectiveness oi the tuned shunt with increaslngcurrent and thereby iiattens out the minimum alternatlng current' voltage curve which is plotted at EL in Figure 7. Even though the normal alternating current voltage drops rapidly when a series choke ls used the ratio between the two alternating current voltages is improved. By the use of choke of slightly less direct current resistance curve 84 may be made flatter.

When the whistle ls not being blown there would be a minimum of 45.8 volts alternating current to open the contacts of the blower motor circuit. @losing the iilterlng circuits, as above described, reduces this voltage to a voltage in the neighborhood o one volt, so that a relay adjusted to drop out on 1% to 2 volts alternating current will give satisfactory operation with reasonable margin for manufacturing tolerances when alternating current voltages of one volt or less remain in the relay coil circuit.

When the above discussed system is to be employed lor toy electric railroads it makes it possible to obtain true directional control of the motor and train `Without moving parts, except :for the manually operable switches. The relay whistlc control is simpler than where the relay is one sensitive to superposed direct current and insensitlve to alternating current.

it is obvious that the invention may be embodied in many forms and constructions within the scope of the claims and I wish it to be understood that the particular form shown is but one of the many forms. Various modifications and changes being possible, I do not otherwise linut myself in any way with respect thereto.

What is claimed is':

i. In combination, a source of alternating current, a full wave rectifier connected to the source and adapted to supply rectified dlrectvcurrent voltage with super-posed alternating current voltage. a principal load normally continuously con` nected with the rectifier to be operated by rectiiied direct current therefrom. a relay having its coll normally continuously connected with the rectifier and sensitive only to alternating current, a second load disconnected from the rectiiier by the relay when the relay isenergized, and a normally open circuit filtering means connectiblc across the rectifier and adapted to reduce the alternating current voltage supplied the relay below that necessary to hold the relay open whereby the relay is released and current supplied the second load.

2. The combination claimed in claim i, `Wherein the principal load includes a motor and rectitiers whereby the motor may be reversed by changing the polarity of the direct current apnlied.

l3. The combination claimed in claim 1, wherela the lterlnc means includes a choke coil and terminals and tuned to twice the frequency of the source. l

4. The combination claimed in claim '1, wherein the filtering means includes a choke coil and condenser shu'nted across the rectifier output terminals and tuned to twice the frequency oi' the source, and a series choke coil.

5. The combination claimed in claim 1, Wherein the filtering means includes a condenser connected across the rectifier terminals.

6. The combination claimed in claim l, Wherein the iiltering means is of such value as to increase the direct current voltage output of the rectifier so that additional voltage is available for operation of the combined loads.

7. A power supply for toy railroads comprising a source of alternating current, a full wave recril tiiier connected to the source and adapted to supply rectied direct current voltage with superposed alternating current voltage, a locomotive having a propulsionv motor normally continuously connected with the rectifier to be operated by rectiiied direct current therefrom, a relay having its coll normally continuously connected with the rectifier and sensitive only to alternating current, a whistle motor disconnected from the rectiiier by the relay whenthe relay is energized, and a normally openA circuit iiltering means connectible across the rectifier and adapted to reduce the alternating current voltage supplied the relay below that necessary to hold the relay open whereby the relay is released and current supplied l the whistle motor.

8. In combination, an electric motor having its field and armature interconnected with one another and the supply line through rectiflers so that the motor is reversible by change of polarity of current supplied, a full Wave rectiiier adapted to supply rectified direct current voltage and superposed alternating current voltage, a reversing switch between the rectifier and motor to control the polarity oi the current supplied the motor, a relay sensitive only to the alternating current voltage and when energized holding its contacts open, a relay controlled current consuming device, and means for concurrently reducing the alternating current voltage supplied the relay to cause it to release its contacts and increasing the direct current voltage supplied so that relay controlled current consuming device and the motor may be simultaneously operated at a higher voltage than. when the motor alone was operated.

9. 'I'he combination claimed in claim 8, Wherein the relay and relay conticlled device are in parallel with the motor and are unaffected by the change of polarity effected by the reversing switch.

10. The method of controlling the operation of two direct current operable current consuming devices connected in parallel one of which is reversible by change of polarity, which comprises operating a full Wave rectiiier to supply direct current of selected polarity with superposed alV ternating current voltage, passing the alternating current only through a relay to keep the circuit for lthe non-reversible current consuming device open, and intermittently filtering out the alter hating current voltage to increase the direct cur-' rent voltage and deenerglze the relay.

vJOSEPH L. BONANN.

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