US1086109A

US1086109A - Rheostat.

Info

Publication number: US1086109A
Application number: US69140712A
Authority: US
Inventors: Nathan Wilkinson
Original assignee: Allis Chalmers Corp
Current assignee: Allis Chalmers Corp
Priority date: 1912-04-17
Filing date: 1912-04-17
Publication date: 1914-02-03
Anticipated expiration: 1931-02-03

Description

N. WILKINSON.

RHEOSTAT.

APPLICATION FILED APR. 17, 1912 1,086,109. Patented Feb. 3, 1914.

2 SHBETSSHEET l.

WAX Waco 53mm 1/ 93K 5 qVAjuQ/vW/OM Mme/WW9 N. WILKINSON.

RHEOSTAT.

A'PPLIOATION FILED 11.17, 1912.

1,086,109, Patented Feb. 3, 1914.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

NATHAN WILKINSON, MILWAUKEE, WISCONSIN, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO ALLIS-CHAIJMERS MANUFACTURING COMPANY,- A CORPORATION OF DELAWARE.

RHEOSTAT.

-of which the following is a full, clear, and

exact specification. m

This invention relates to rheostats, and more particularly to water rheostats.

ater rhcostats have been made wherein the electrodes are both movable and stationary and the eifective resistance in the first type is varied by raising and lowering said movable electrodes out of and into water while in the latter type the resistance is changed by varying the height or amount of water with respect to such electrodes. In other words, with respect to stationary electrode type of water rheostats,the effective resistance of such rheostats-is varied by causing more or less of ,the electrodes to-be immersedby raising and lowering the level of th'e water. Such rheostats are being employed more and more for starting motors, such as induction motors. In starting such motors, and motors of various types, comparatively little time is required to accelerate the motors from a position of rest to full speed. Often times it is necessay that the original effective resistance be fairly high. In order to reduce this high resistance within a. comparatively short time, a

ump of comparatively high capacity will be necessary to pump the water. A motor of corresponding capacity will be necessary to operate the pump. The cost of such an equipment in many instances is quite high.

It is therefore the object of my invention provide a simple and compact water rheostat adapted to meet all of the requirements of commercial op ration, and one which can be operated at a minimum cost. This object is accomplished by providing a water rheostat wherein the electrodes are stationary and are located in water at all times, the effective resistance of such rheostat being varied by raising and lowering an insulated or insulating member or members which are interposed between or surround such electrodes.

The various novel features of my invention will be apparent from the drawings and the description, and will be particularly set forth in the appended'elaims.

Specification of Letters Yatent.

Patented Feb. 3,1914.

- Application filed April 17, 1912. Serial No. 691,4 07.

The invention is illustrated in the accompanying sheets of drawings, in which- Figure l is a vertical sectional view of-mv water rheostat; Fig. 2 is a sectional view of the same rheostat taken on the line 2-2 of Fig. 1, looking in the direction indicated by the arrows;.Fig. 3 is a vertical sectional view of a water rheosta't which is a modificationof the one shown in Figs. 1 and 2; Fig. 4 is a horizontal sectional view of the rheostat shown in Fig. 8, the section being taken on the line 4-4 of Fig. 3, looking 'in the direction indicated by the arrows Fig. 5

is a diagram of connections showing the.

rheostat illustrated in Figsfl and'2 as connected in the secondary circuit of arr-induction motor; and, Fig. (3 is a diagram of connections showing the rheostat illustrated in Figs. 3 and 4 connected in the secondary circuit of an induction motor.

This rheostat i ncludesa receptacle or tank 10 containing a fluid 11, preferably water, the height of which may be seen by observing tliedndicator 9 secured to the upper part of said receptacle. This receptacle is provided with a cover 12 normally retained closed by any suitable means, such as by a bolt and nut 13, said cover being provided with a central opening 1 1 through which a rod 15 is guided. Secured to the lower end of the rod 15 is an insulated or 1 lnsulating frame 16 including a plurality of downwardly projecting members 17 which form batlles, to be referred to hereinafter. Also extending through the cover 12 are conductors .18, to the lower ends of which are secured conducting plates 19, and connected to these conducting plates 19 are groups of electrodes 20, 21, and 22. The conductors 18 also pass through the frame 16, being insulated therefrom and insulated from the cover 12 by bushings 23 having collar portions 21 whi'di hold said bushings in a fixed position relative to the cover 12. The conductors 18 are provided with C01- lars 25 to hold said electrodes in a fixed position in the receptacle 12. These electrodes are suspended from the cover 12 by the conductors 1 8, there being four such conductors in this particular case, one conductor leading to each of the groups 20 and of the'electrodes and the other two leading to the electrodes 21. From an electrical standpoint, one.conductor 18 would be sufiicient for the central group 21 of elecbetween electrodes develops heat at. the bottrodes, but two are used in this particular 1 case primarily to mechanically balance said middle group 21 of electrodes, the rod 15 being located between said two conductors. An electrical balance is, however, obtained by providing the middle group of electrodes with two conductors, and in some cases this may be desirable. 'F' ch of the groups of electrodes is provided with electrodes of difterent lengths for the purpose of making the value of efi'ective resistance more marked 1 under different conditions. These electrodes are interposed between the battles 17, or groups of electrodes and the baiiies are spaced alternately with respect to each other.

The :bafiies as a unit may be raised and lowered relatively to the electrodes by any suitable means. In this particular case, for the sake of illustration, I have shown fluid pressure means for effecting the desired result. Secured to the rod 15 is a piston 27 which is adaptcd to be actuated in acylilr; der 28. In the position shown the piston and baiiie plates are in their lowest positions. The piston may be forced to the upper end or the cylinder by rotating the handle 29 in a counter-clockwise direction until the valve opening 30 registers with the openings 31 of the supply and connecting pipes and respectively. In such position, fluid under pressure passes from pipe 32 hrough the valve 30, pipe 33, and under the piston, gradually raising it and the battle plates to the desired position. The battle plates and the piston may be lowered due to the weight of said part by rotating the handle 29 in a clockwise direction until the valve openings 30 and 3e register respectively with the openings 35 and 31 of the exhaust pipe 35 and connecting pipe 33. By means or this valve and similar arrangements the rheostat may be controlled from a remote point.

As shown, the rheostat is in full resistance position and it connected in circuit with a motor for accelerating or regulating purposescurrent would pass between the cen tral group. of electrodes 21 and the electrodes 20 and 22 respectively and current would pass between electrodes 20 and 22 through the tank 10 and through the water between said tank and said electrodes 20 and 22. In this position the current passing tom of the baflle plates and electrodes. Therefore the, water at the bottom portion of the battle plates and electrodes becomes heated and rises between the baflie plates, escaping upwardly through the frame 16, coming into contact with the cooling coil 37 having an inlet 38 and outlet 39. Cold water is referably circulated through this cooling coil 37 which may be supported in the tank 11 by brackets 10 having pins 41 for separating the adjacent turns of the coil. As the heated water at the bottom of the baffle plates rises, cold water rushes into its place. A natural circulation is thereby provided, maintaining the water in the rheostat at the desired temperature. It is to be noted that the electrodes are located near the bottom of the tank, the tops 01"- the electrodes being below the middle of the tank. comparatively large volume of water. is above mentioned, the bottom of the electrodes and bullies and thereupon rises to the top of the tank and out of contact with any parts of the electrodes. In fact such heated water becomes far removed from such electrodes. This means that cold water is being continuously circulated to those parts of the electrodes from which heat is being conducted. In this way the water is kept at the lowest possible temperature.

In order'to decrease the eiiective resistance of the rheostat', the bafiie plates are raised as unit by the fluid pressure means above referred to. These baiile plates may be gradually raised until the lower ends of said battle plates are raised beyond the upper portions of the electrodes. In this position minimum resistance is offered to the current passing from electrode to electrode; When it is desired to cut in resistance the balile plates can be lowered by their own weight by moving the handlej 29 to the proper position to permit the fluid under the piston 27 to exhaust. These bailie plates are preferably somewhat wider than the electrodes, as shown in Fig. 2, to increase the path of current which may pass around the baili'es between the various groups of electrodes, especially when the rheostat is in full resistance position. The. r.eceptacle 10 is provided with an inlet 4A and an outlet 45 so that a fresh supply of water may be easily provided at any time.

Instead oi having the electrodes in the form of plain plates; as shown in Figs. '1. and 2, the electrodes may take the form of conducting cylinders 16, L7, and 48, as shown in the modification in Fig. 3. In this modification the baflies, which may be made of tile or any other insulating material, are also shown in cylindrical form, the

various battles

49, 50, and 51 completely surrounding the groups e8, 17, and -16 of electrodes. For mechanical purposes,each of the groups 16, 4:7, and 18 of cylindrical electrodes is suspended from the cover 52 by two diametrically

opposite conductors

53, 53 and 53*, respectively, as shown diagrammatically in Fig. 6. An electrical balance is also obtained in this way. In this instance the longest of the central group of electrodes is directly electrically connected to the tank 54, as shown in Fig. 3, so that current between the central group of electrodes -18 the water is heated near a sence and outer group 46 may be conveyed more directly from one to the other. The efiec- 'tive resistance of this rheostat is varied in precisely the same manner as described in connected in the secondary. circuit of an induction motor of the wound rotor type. Its use, however, is not limited to this particular application, but such rheostat may be used with different types of apparatus.

for various purposes.

There may be various modifications and arrangements other than those here shown and described, and it is my intention to cover adll such modifications and arrangements which do not depart from the spirit and scope of my invention, as set forth in the appended claims.

What I claim as newis:

1. In a rheostat, the combination of a receptacle containing a fluid, stationary electrodes in said fluid, and movable battles-interposed between said electrodes and displacing only their own Volume of liquid for varying the effective resistance of said rheostat. v

2. In a rheostat, the combination of a re ceptacle containing a fluid, stationary electrodes in said fluid, and movable baffles permitting free circulation of fiuidltherebetween and interposed between said electrodes for varying the effective resistance of said rheostat.

3. In a rheostat, the combination of'a. re-

ceptaole containing. a fluid, groups of stationary' electrodes of different lengths within said receptacle, and movable means interposed. between said groups of electrodes for varying the efiective resistance of said rheostat. v

4. In a rheostat, a receptacle having a cover and containing a liquid, stationary electrodes suspended from said cover and immersed in said liquid, and movable barriers separating said electrodes for varying the efi'ective resistance of said rheostat, said barriers being openly connected as a unit to permit their free movement in said liquid.

5. In a rheostat, the combination of a receptacle containing a liquid, stationary electrodes supported in said receptacle, and movable bafiles interposed between said electrodes and being freely movable in said liquid as a unit for varying the effective resistance of said rheostat.

6. In a rheostat, the combination of a liquid containing tank, groups of electrodes within said tank, the electrodes of each group varying in length, and movable means i is including a plurality of bafiies movable as a unit to vary the effective resistance of said rhcostat.

7. In a rheostat,thecombination of a receptacle containing a liquid, stationary electrodes in said liquid, and movable means surrounding said electrodes and displacing only its own volume ort=liquid for varying the effective resistance of said rheostat.

8. In a rheostat, the combination ot a tank containing a liquid, stationary electrodes in said liquid, and a member surrounding one of said electrodes adapted to be moved relatively thereto for, varying the eiiective resistance of said rheostat and to displace nly its ownvolume of liquid in its movement. 9. In a rheostat, the combination of a receptacle containing a: liquid, stationary electrodes immersed in said liquid, and movable baflies interposed between said electrodes and between some of said electrodes and said receptacle for varying the 'efi ective resistance of-the rheostat, said baffies being freely 1novable in and displacing only their own volumeof said liquid.

10. In a rheostat, the combination of a tank containing a liquid, cylindrical eleotrodes in said liquid, and a member movable rheostat without substantially changing the level of said liquid.

11. In a rheostat, the combination oi a re ceptacle containing a liquid, a plurality of stationary cylindrical electrodes in .said liquid, and a cylindrical nonconducting member having an opening in each end and movable with respect to said electrode for varying the effective resistance of the rheostat.

12. In a rheostat, the combination of a liquid containing tank, groups of stationary spaced and connected cylindrical electrodes, and a plurality of movable non-conducting cylindrical members interposed. between said groups of electrodes and being movable as a unit for varying the effective resistance of said rheostat.

13. In a rheostat, the combination of a liquid containing tank, groups of stationary spaced and connected cylindrical electrodes, a plurality of movable non -conducting cylindrical members interposed between said groups of electrodes and being movable as a unit for varying the effective resistance of said rheostat.

Il. In a rheostat, the combination of a receptacle containing a liquid, stationary electrodes 1n said liquid, one of said electrodes being. in contact with said tank, and

with respect to said cylindrical electrodes for varyingthe QiIGCtlVE resistance oi said fluid containing receptacle, a stationary electrode in said receptacle, and a movable member arranged concentrically with respect to said electrode andhaving an opening in each end for varying the effective resistance of said tank.

16. In a rheostat, the combination of a receptacle containing a liquid, stationary concentrically arranged electrodes in said liquid, and concentrically arranged members freely movable and displacing no more than their own volume of said liquid for varying the effective resistance of said rheostat.

17. In a rheostat, the comhinatimi of a tank containing a liquid, stationary concentrically arranged electrodes in said liquid, and movable concentrically arranged members surrounding said electrodes and being arranged alternately with respect to said electrodes for varying the efiective resistance of said rheostat Without substantially changing the level of said liquid.

18. In a rheostat, the combination of a receptacle containing a liquid, stationary electrodes immersed in said liquid, and a movable bafile for varying the effective resistance of said rheosta-t, said electrodes being located in the lower half of said receptacle so that liquid hea d at or near the electrodes may circulat 3 from said elec trodes to a remote part of the receptacle for cooling.

19. In a rheostat, the combination of a receptacle containing a liquid, stationary electrodes immersed in said liquid, a movable baffle for varying the effective resistance of said rheostat, said electrodes being located in the lower half of said receptacle so that liquid heated at or near the clecfluid containing receptacle, electrodes thcrein, one of said electrodes having a plurality of conductors connected thereto for electrical balance purposes, and a member movable relatively to said electrodes for varying the eiiective resistance of said rheostat.

21. The combination in a receptacle con taining liquid, of electrodes, a plurality of battles freely movable as a unit between said electrodes, said baltles and said liquid acting to create a resistance path of variable length between said electrodes, and cooling means in said receptacle adapted to cool and circulate the liquid that has become heated between said electrodes.

22. In a rheostat, a receptacle containing fluid, electrodes, and a baille adapted to act as a barrier between said electrodes, said baflle and said electrodes being wholly immersed in said fluid in all current carrying positions of said parts.

23. In a rheostat, the combination of a receptacle containing a fluid, electrodes in said receptacle, and bafiles interposed between said electrodes, said baflles and said electrodes being relatively movable for varying the effective resistance of said rheostat and permitting free circulation of said fluid between said parts. Y Milwaukee, Wis., April 3, 1912. In testimony whereof I aiiix my signature, in the presence of two witnesses.

NATHAN WILKINSON. Witnesses:

CHAs. .L. BYRON, Ron. E. SToLL.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents 1 Washington, D. C.