US867810A - Automatic accelerating-controller. - Google Patents

Description

PATENTED OCT. 8,

APPLICATION FILED JAN.15,1905.

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H [I I WITNESSES ATTOFI. NCY

PATENTED OCT. 8, 1907.

A. G. EASTWOOD. AUTOMATIC AGGELERATING CONTROLLER.

APPLIOATION FILED $1111.15, 1907.

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mvcn'ron m c Y E N w w ATTORNEY UNITED STATES PATENT l OFFICE.

ARTHUR. o. EASTWOOD, or CLEVELAND, on o;

AUTOMATIC accELEnATrNe-conTnoLLnR.

Specification of Letters Patent.

. Patented o er; s, 1907.

Application filed January 15, 1907. Serial'No- 352,407-

I To all whom it may concern: Be it'knownthatl, ARTHUR C. Ess'rwoon, a citizen of the United States, residing at Cleveland, the county oi'Ciiyalibga and Stateof Ohio, have invented or dis covered new'and useful improvements in Automatic Accelerating-Controllers, of which the followingis a specification.

' My invention relates broadly controllers of theautomatic acceleration type for electric motors. More specifically, my invention relates to controllers of the said type wherein the acceleration is made at a fate independent of the operator and wherein, under normal condition, it will be impomibleto exceed a predetermined accelerating current,

- The objects-of my invention are to produce a con- '25 taneously lowers the voltage applied to the solenoid of the succeeding switch, thereby, preventing the succeeding switch irom closing so rapidly as to prevent the "proper action of the current-controlled relay;. -wherein the current-eontrolledrelay does not, upon the flow of an excess current, open the actuating circuit of the switch which is about to close, but rnerely sicts to inserts; resistance in'series with the coil of the switch, which serves to denergize it no further than is necessary to prevent the closure of the switch; wherein the resistance, which serves to prevent the closure et a switch upon the passage of an excesscurrent, acts subsequent to the closure of the switch to reduce the How 01 current thrpugh the actuating coil of the switch; where n the winding of the current- 40 controlled relay is so onnectedthat it will be automatically short-circuitcd when the last resistance switch closes; and where n the winding of the currenteontrolled relay is so connected that identical relays may be used in the controllers varying widely in capacity, thereby adding to the interchangeability of parts and effecting more economical production. Referring to the accompanying drawings, Figure l is a diagram of connections, oi one form of a controller constructed in accordance wih my invention; Fig. 2,- a vertical section of my preferred form of current-con-r trolled relay and its inelosing (asing; and Fig. 3, a side elevation of the same.

In Fig. 1, U, U, D, D", S, S, and S are magnetically operated switches, the switches D, U, S and S being respectively provided wi th the auxiliary switch contactswi, u, s', and s which are closed when the corresponding switches are closcd.' The "switch S "is provided with an auitiliary switch x which is 'closcd when switch S is open and-opens when switch S closes.

S is a main knife switch connecting the controller to a source of current supply.

A is the armature and F, the' serie'sfield winding (if the motor to be controlled.

M is the master switchwhic'h is moved by the operator to start, stop, and reversethe motor.

b is.the winding of a blow-out magnet, with which each of the said magnetically operated switches is pro.- vided. i p

R, R, and R are sections ota starting resistance controlled by the switches S, S.,"and S". R is also a bank of starting resistance, any portion of which,

may be connected .in'paralle'lfwiththesection -R through thcwinding o 'otth current-controlled relay O. The resistance ,R is provided with 'a number of taps whiclipermitof an'adjustable connection as will be later described. 'The switches S, S,- and S each have an auxiliary section ot'resistancedesignated respectively as r, r, and r so connected thatwhen the switch 8, controlled by the current-controlled relay sage of an excess current through the 'winding 'ot the relay 0, this resistance is placed in circuit The re 'sistances r tor" are so proportionedthat; whnthey are included in the circuit of their respective coils, suflicient current will not flow to cause the switch to close, but will permit suflicie'nt-current to flow to maintain the switch in the closed condition after it has once operated.

The operation of my controller is as follows: Assuniing that the lover of the master switch M is moved the right so that the brush makes contact with the segment d, current will then flow from the positive side of the switch S through the winding of switches D and D, thence through the wire 12 to the contact d and the brush of the master controller M to the nega-v tive main. This causes the switches D and D to close. Switch D in closing closes theauxiliaryswitch :1. The closure of the switches D and'D establishes the circuit through the motor is follows: From the positive side of the switch S, through the wire 7, the series field winding F, the. wire 6 the resistance sections R. and R, at which latter section the current divides, part of it passing through th resistanee R and part through the resistance R and the winding of the current-controller relay 0 to the wire 5, where the divided current reunites and flows thence through the contacts of the switch D, the wire 8, the armatiire A of the motor, the wire 9, and the D, to the negative side of -the switch S, thus completing the circuit through the motor, which will cause ro- 8'0 0 ,is closed, these sections of resistarice areshort circuited and when the switch 3 is opened by the tober 11th, 1904. By this arrangernent the coil'in' each switch is energized by the line voltage minus the drop through a certain portion of the starting res igan e,.Whereby the voltage applied to the coil of the sw'itchis reduced proportionately with any increase in the current drawn by. the motor. As soon, however, as a given switch is closed, the portion of starting resistance previously in circuit with its winding is short circuited through the closure of the switch.

- At the instant of starting the rirotm, the section of resistance Ris in circuit with the winding of switch 8'. Sections Bi and It are in circuit with the winding of switch 8 and sections R and R connected in series 'R and R connected in parallel are in circuit with the winding of switch 8". As soon as switch 8 closes, the mistance R is short circuited, thus cutting out the resistance-in circuit with switch S and reducing the resistance-in circuit with switches S and SK- Sirnilarly when switch S closes, the resistance is clirninstcdirom the circuit of switch 8 and resistance reduced inrthe circuit of switch 8?. When switch-S p n 1 closesjall bubs resistance is short circuited.

D and D having closed as previously desr'zibed, the control circuit is as follows:

From the positive main through the wire 7, the field F,

sis-wire mils starting'resistance 11 the winding of the switch'S thewire'18, the ar lxi liary contacts .9 of the thewirc 17, the contacts 0, O, and '0 ofthe current controlled relay 0, the wire 16, the guxiliary switch I! controlled by the reversing switch' D, the connection 15, the wire 12to the master con-: troller M, and thence through the contact :1 and the: brush of the controller to the negative main. 1 This circuit is as traced on the amumption that only normal current is posing to the motor, and, therefore,-

- that the current-controlled relay Ohas not acted 'toopen theswitchcontactsOtoO'. Ifthis'is the case,

switch 8' will'close. In case an excem current is flowf ingtothermtontheswitch contactsO toOwill be! opened hythe current-controlled relay. 0. The of the through the-winding of the switch will l-hfli be from the positive main, the wire 7, the field 'F, the wire 6, the section B of the resistance,

through the "winding of the switch 8, the. resistance'-1, the wire 16, the auxiliary switch d, thev :i- "connection 15, the wire 12, and thencethrongh the.

eontactd and'the brusho'fthe master controller )1 to;

' sis "thenegativemain. 'Itwillthusbe seenthatthere-= 1 sistanee r is in circuit with the winding oi'switch S and, as previously stated, thisi'esist'ance is oo proportinned thatputiicient current is not pe mitted to psss' to muse theiwitchS to When the tlnwin'gto the has reduced to the-normal value;-'the -switchS, controlled by the current-eon-i trolledrela'y 0, will close, 'thirs'completing the paththrough the circuitof the winding of'the switch 8 as originally traced, this'circuit by-passing or short cib;

cuitingther permitting theswitch to i negative innin. '-Switch Sthen closes. T

close. The.switch -S in closing, short circuits the '15, the wire 12,' and the master controller to the negetive main. As previously mentioned, the resistance r* is so proportioned that, under the condition just described, the switch S"'will not close. At the same time, the voltage applied to the winding of-swiichS" is reduced through the drop in voltage caused by the passage of an excess current through the resistance R". As the current is reduced through the speeding up of the armature,'.the drop through the resistance R is reduced and when. the proper reduction in current is effected the switch 0 clones. This short circuits theresistance r and permits current in tlow from the positive side of switch-S, the wire '7, theiield F,the wire 6, the main contacts of switch Shthe section R of the resistance through the winding-oi switch S, thence through the auxiliary switch I the switch S, the switch O,.the wire 16,=the switchii, the wire 15, and the wire 12, and'themaster controller M'to the Switch 5 operates; in a sinriiar minn'er.

opensthe path through the sf to fthe master controllers The resistance r is then in series switch S- closes,'it opens the auxiliar'y'switchs'ind .95

with the winding of the switch S; Fin 7 series with th e winding ot-the Bfliiid'thto Gish-n08 H in series with the windin'g aims-midis.

This serves to cut down' the hrnmmtot by the windings of the switchm and heating of the windings; It will switch s' in closing short'circuitsthewinding'oi uifs A current-controlled relay 0. Thiswinding'is, I I

in circuit. only during the period may, therefore, be designed for intermittent service. When'tlie. operating lever oithe-mssta'contoller M is' moved in the reverse direction from the (imposition, that is to any, with im contact-"brush in contact with the segment 10, the reversing switches U and U will close in .place of the reversing switches l) and D. This causes current to pass through the armature of the motor in a directionthe-reverse of that above described, which the armature, to revolt":- in the reverse direction, as bereadily-understood. In this case; the control circuit is completed through the auxiliary switch u in :plalre of the auxiliary switch d, the remaining circuits and the operation of the-remaining switches being'the samems above described,-

As previously mentioned, during the acceleration of thernotor, the current flowing to .the motor divides at the end of the section It eithe starting resistance, .part

ot'itipsmingdirectly through the-section R of the re distance to the wire '5- use m of it passing through the resistance R; the 'wire 1. the winding or the cirrrentcontrolled relay 6 arid the wire 10 to the wire 5. Ctrrent will. divide through these 'two paths in inverse, I

proportion to the resistances of the paths according to the well known law. For instance, if the resistance of I the path through the resistance R and winding of the current controlled relay is precisely the same as the resistance (ii-the section it; exactly one-half oi the current will flow through the.winding of .the relay '0.

If more resistance be included in thesection Rflless' than onehalf of the current being taken by the motor This, thereiorq lorms a ready means of adjusting the 'the switches S to S:

lnarginnuripurrerit which maybe drawn by the motor b eiore the current controlled relay will act to open the switch a and thus interrupt -the successive action of lay O in the ease ()flDOtQIS differing widely in power for the reason that any proportionoi-the motor current from zero to the full current'ldkeri bythe motor may. he made to pass through. the-"winding oi the relay by adjusting the resistance Was above described, For instance, if astaudard relay is wound for a capacity of 100 ampercs, the entire current would be passed through:thewinding of the relay incase of a motor which required an acceleratingcurrent of 100 amperesl Ii a larger anotor required an accelerating currentof 200 auipcrcs, one-hall of the total current will be passed through the relay. Similarly, in case of a motor requiring dillkanrpen-s, onc'= iu u1'tl 1 of the-current would he passed through the relay:

' From the description previously given, it will be zip parent that the initial rush of current cruised by the closure oi each of the switches S and S reduces the voltage applied to the succeeding switch hy virtue of the drop in voltage caused by thefpassage of excess current through the'porliou oi the-resistance in circuit with the i'wi nding oi the succeeding switch. This gives the current controlled relay 0 an opportunity to act before full voltage is applied to the winding oi'the succeeding switch. The current controlled relay() in acting does not open the circuit of the winding of the succeeding switch, but merely inserts thecorrespouding resistance of the r-series' ofresistancesin-circuit with the winding, or rather, opens the shortcircuit around the resistance 1', which permils current to flow through the windingoi the succeeding switch, but limits the value of the current to such a point that the switch will not close. Therefore, the operatingelectro-magnet of the switch is not entirely dencrgi z'cd and the switch will close much more quickly when the current-controlled relay returns to its normal position than would be the. case if its circuit had been entirely open and its electro-magnet entirely denergizcd hy the. action of the cl;went-controlled relay. Thereason for this is on account oi the iactthai; the building up of the magnetic flux in any electro-magnct, particularly one. in which the magnetic circuit is not laminated, requires an appreciable interval of time.

in Figs. 2 and 3, N is a base, such as slate, upon which the parts are mounted. O is a magnetizing coil of the relay 0 which is provided with terminals O and 0* extending through the base N and provided It will be further understood that this construction makes it possible to use'a periectly standard winding for the currcni controlled,re

with suitable attachments for connecting the winding. -in circuit. ,The coil O- is mounted upon and suitably insulated from a nOn magnetic tube 0 P is-a casing,

preferably ,of cast iron 'in which 1 the apparatus is mounted. This casingis closed at itsrear side by the base N and its'front side is proyided' with a remoyalile cover p so constructed that, whentheflcoyerfisin place, the apparatus is completely incloeed, The non magnetic tube 0 is tapped into a cross piece-Pwithin the case-and a yoke of magnetiomate'rial p is slipped over the upper end of the tube and rest's'iiponshoul ders P in the. case... Q is the plungeroi the electroinagnet, which, upon the fiowoi a predetermined-cur.-

rent through the winding 0 rises and lifts the contact I disk Of from contact-with the pins 0? and I The .disk 0 is suitably insulated from the pliinger as indi bated. .Theupward motion of the plunger is limited by the lower end of the brass tube 0. It will be note d that the plunger 0 when in its-uppermost position by.

no me,ans completes the magnetic circuit oi the elec-- ire-magnet, there being still a considerable air gapbetween the upper end of the plunger aridthe yoke p. This is for the purpose of rendering the relay more sen-- sitive in action,- particularly in causing the plunger 0 iodrop when the current flowing through the,ruagneii- 'izing winding 0 is decreased to the neceemryextent.

The cover p' -oi the casing fits in a slot p at lower end and is pr'oyided near its upper end with ,ahook p, which engages with the end bia-piyoted-latch p,

which is made of magnetic 'matcrialand-is iricloaed' within the case', so that there is no ready means of gainingaccess to it mechanically. To releasethe latch 'so. th'atthe doorp may be removed the pole of a magnet will be placed above the latch atthe point-p,

which will'cause the rear endof the latch to tis,-, thereby relcasing iis hooked end irorn thehook p.

This construction is adopted to prevent others thanthose properly equipped for caring for the apparatus -frorn gaining access to the relay coiland interfering th crewith I v I The screws 1) and 10 which secure the casing to the 'base fit in counterbored holes in the base N and are preferably sealed in place so that they cannot lie readily tampered with.

In an electric controller, sections of resistance, mng-.

2. In an electrlecontroller, sections at resistance, mngnetlcnlly operated switches for controlling su'dreslstance. the last or said resistance sections to .lie cut out being made up of two bauksot resistance in parallel, and n governlngrelay having its winding in series with one of said parallel banks of resistance.

4. in an electric controllen's'ectlons of resistance for limiting the flow of current to a motor, magnetically o1 erated switches for controlling said resistance, each of said switches having one end at its winding connected to a point on said resistance, an auxiliary resistance connected to the remaining end 0! each or sold windings and 4 ao' gam I to one side oi! the supply circuit, an auxiliary switch operatively connected with each of said first named switches and controlled by the next preceding switch, a short-circuit including the auxiliary switch of said last named switch, the short-circuit passing around each auxiliary resistance,- and a currentcontrolled relay having its con- I ta'cts in the path short-circulting said resistance.

In an electric controller, a motor circuit, .the combination of sections of resistance in the motor circuit, magn'eticahy operated switches for controlling said r'esistance,'

each of said switches having one end of its winding connected to one of the supply mains through a portion of said resistance. and an auxiliary resistance for each' wind:

. ing having one end connected to the remaining end of said winding and the other end thereof to the other supply main.

(i. in an electric controller, the combination of sectionsof resistance in a motor circuit and magnetically operated the supply mains through a portion of said resistance, anv

auxiliary resistance for each winding having one end connectcd to the other supply main and the other end tothe remaining end of said winding, and a current-controlled relay having contacts which short-circuit said auxiliary resistance when less than a predetermined current is flowing through the winding 01 said relay. i

" 8. In an electric controller, the combination of sections of resistance in a motor circuit, magnetically operated switches for controlling said resistance, each of said switches havlng one end of its winding connected to one 0! thesupply mains through a portion oi! said resistance, an auxiliary resistancefor each winding having one end connected to the other supply main and the other end to the'remainmg end of said winding, and means for shortcircuiting said auxiliary resistance, said means comprising an auxiliary switch closed by the closure of a preceding resi stancecontrolllng switch and a current-controlled relay.

9. in an electric controller, a motor circuit, a. series of separately actuated magnetically operated resistance switches, a separate auxiliary resistance for each switch .and in series with the winding of its respective switch, and

means or short-circuiting said resistance when the current'talls'below a predetermined strength.

10. In an electric controller, a motor circuit, a. series 0! separately-actuated, magnetically-operated resistance switches, an auxiliary resistance in series with the winding of each switch, a short-circuit around the auxiliary resistance of each closed resistance switch, and means for opening the short-circuit when the current in said circuit rises above a predetermined strength.

11. In an electric controller, a resistance, a series of separately actuated magnetically .operated resistance switches, and a relay for controlling the said switches, the winding of said relay being in shunt to a portion of the resistance controlled by the last resistance switch whcreby said winding is short circnited when said last resistance switch closes.

12. In an electric controller, the combinations of sec tions a! resistance, magnetically operated switches for con trolling said resistance, a current. controlled relay having a single winding and governing the closure 0! said switches, and means forwarying the proportion of current which will flow through the winding oi! said relay.

Signed at Cleveland/Ohio, this 10th day or January, A. D.-1907.

an'rnnn'c. EASTWOOD.

Witnesses:

J. E. Wanunn, M. N. Run.

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