US1584673A - Thermal relay - Google Patents

Description

B. H ssmm-a May 11 1926.

THERMAL RELAY 2 Shams-Sheet 3 Filed Feb.

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mvENToR m H. SmiI/z 1/ Bly'am ATTORNEY 5. H. SMITH May 11 1926.

THERMAL RELAY Filed Feb. 26. 1921 I 2 Sheets-Shet 2 .INVENTOR Bery'a hh. Sm/#7.

A'I'TORNEY WITNESSES:

Patel-flied May 11, 1926. I I 1 UNITED STATES PATENT OFFICE.

BENJAMIN E. SMITH, OF WILK INSBURG, PENNSYLVANIA, ASSIGHOR T WESTDTG- HOUSE ELECTRIC 8t MANUFACTURING COMPANY, A COBPQEJATIQN OF PENN"- SYLVANIA.

THERMAL RELAY.

Application filed February 26, 1921. Serial No. 4118,1 34.

My invention relates to relays and partion therewith of the indicators of the con- 65 ticularly to thermal relays. tact nembers I One object of my invention is to provide Fig. 7 is a side elevational view of the dial a thermal relay that shall have a long time and the indicators illustrated in Fi 6; and:

element in its operation. Fig. 8 is a diagrammatic view 0 an elec- Another object of my invention 18 to protrical circuit, illustrating the connections 00 vide a relay. of the above indicated characthereto of the relay embodying my inventor. for protecting electrical apparatus and tron.

that shall reproduce substantially the temlieterrihg to-Figs. 1 and 2, the device em- 10 pew/cure onditigns bt ining in the appaundying my invention, c.ompr1ses,1n general,

rams a supporting base 10, a relay 11 supported 6 A further object of my invention is tot thereon and a cover 12 that co-operates with provide a relay of the above indicated chap thebaseltl to enclose the relay 11. The base actor that shall be simple and economical in 10 is provided With two supporting brackets '15 its construction and reliable in its operation. 13 and 14, each of which is provided with a In practicing my invention, I provide two threaded rod -l5 that extends outward from "J spirally-wound bimetallic members that are the r Ilt 0f the relay and co-operates with mounted on a movable shaft. The inner & thumb crew 16 to hold the cover 12 in ends of the bimetallic members are electriposition. Threaded portions 17 that extend 20 cally connected through a sleeve of confrom the rear of the base 10 co-operate with ducting material that is securely mounted on a i h board 01' some similar supporting 7 the shaft and insulated therefrom. The ev ce to Support the relay in any desired outer ends of the bimetallic members are P EI H. secured to stationary terminals that are dish relay ll comprlses a fluid-containing posed on an enclosing i Th bi t lreceptacle 20 that is mounted'on, and suplie members are traversed by the circuit cur- P r d by, a Supporting member 21 which is rent, and, when heated, turn the shaft upon secured to thebase .10. Supported within which they are mounted to effect engagement he receptacle, between two bearings 22 and between two contact members. The bimetal- IS a Shaf 24 upon which is disposed a lie membersare immersed in oil or some tube 95 9f insulating material. Upon the similar fluid having a large heat capacity. tube 25 1s ly n d a le v 26 of so The combination of the fluid and the bime- Conducting material.

tallio member so increases the thermal- TW spirally-wound bimetallic memb rs storage capacity of the relay as to reproduce 27 n 28 are supp rted by the conducting substantially the temperature conditions in Sleeve 2 n h ve their inner ends'secured th l t i l apparatus th t i t b thereto, being thus electrically connected to no tected. each other. The outer ends of the members gum 1 of h accompanying d i i 27 and 28 are respectively connected to two a front view. partially in elevation and partglmlnal m r 29 and 30. The terminal w in tialiy in section, of a thermal relay embod members 29 and 30 are connected by flexible m my i ti I conductors to terminal members 31 and 32, 95

Fig. 2 is a side view, partially in elevation where y the bimetallic members 27 and 28 and partially in section, with parts broken of the relay may be connected in circuit with away, of the relay shown in Fig. 1. the external conductors of the main circuit Fig. 3 is a plan view of: the relay taken which is to be protected.

along the line III1II of Fig. land illus-' A spirally-wound spring 33 is disposed 2.00 trates the contact-adjusting member. around the insulating tube 25 and has the Fig. 4 is a plan view of the adjustable inner end thereof secured to the tube and the. contact-supporting member of the relay outer end secured to the fluid-containing reshown in Fig. l. ceptacle 20. Also men lnpon the shaft of F 5 is a plan view of the movable the insuiat-in a contact member 10 contact-supporting member. 34, the moi 01 cinch. with the shai'it Fig. 6 is a front elevational view of the 24, is GOIltIOll i by the expansion or contrac scale of the relay, illustrating the co-operation of the The spring? 33 serves as a conducting means to connect,

the contact member 34 to an external control circuit, as illustrated in the diagram of Fi 8.

Th the path of the movable contact mem ber 34 is an adjustable contact member 35 that is adapted to be engaged thereby. The contact member 35 is secured between one pole of a circular permanent magnet 36 and a supporting disc 37 of micarta, as illustrated in Fig. 4. The disc 37 of micarta is disposed on, and supported by, the spindle 38 of the member serving as the bearing 22.

The contact members 34 and 35 are disposed on supporting members 39 and 40 of magnetizable material, and the engagement of the contact members is, therefore, effectively maintained. The disengagement of the contact members is effected with a snap action by reason of the force of the tensioned bimetallic members 27 and 28 acting upon the contact member 34 to disengage the same from the contact member 35. The po-v sition of the contact member 35 is controlled by the adjusting member 44 whichis retained in such position as it may be placed and. prevented from moving therefrom,. because of jarring or vibration, by means of a flexed spring 45.

Thecontact members 34 and 35 are connected to two terminal members 46 and 47, respectively, to permit convenient connection thereto of the conductors of an external control circuit.

The supporting members 39 and 40 of the contact members are provided with pointers 41 and 42, respectively, that co-operate with a stationary scale. 43 to indicate, respective ly, the position of the'movable and of the stationary contact members, as illustrated in Fig. 6. The scale may be calibrated for average value of current or temperature or for percentage of full-load circuit.

The fluid container is provided with a window or opening 48 through which the position of the contact members 34 and 35 may be observed.

, Thebimetallic members are immersed in oil or some similar fluid having a large heatstorage capacity and they thus serve to simulate the heating conditions of an electrical apparatus which is to be protected by the relay. The temperature of the bimetallic members will thus vary substantially in accordance with the temperature of the conductors of the apparatus that is to be protected and such control as may be desired .may be obtained by means of a control circuit, the energization of which is controlled y engagement of the contact members.

As illustrated in the diagram shown in Fig. 8, a translating device 50 is adapted to receive energy from the source 51 of elec tromotive force through the circuit interrupter 52. The circuit current that traverses member controlled by the shaft and an oilthe translating device 50 also traverses the bimetallic elements 27 and 28 and, be cause of the surrounding oil, heats those members substantially in accordance with the heating of the translating device 50. When the temperature of the translatingdcvice 50 and, accordingly, the temperature of the relay attains a. predetermined value, engagement of the contact members is effected to complete a control circuit for tripping the 7 interrupter.

It will thus be observed that, by immersing in oil or some other such heat-storage fluid, a bimetallic member that is traversed by the same current that traverses the translating device, a thermal relay may be obtained which will closely simulate the temperature conditions obtaining in the translating device.

My invention is not limited to the specific 85 arrangements or'details as illustrated, since various modifications may be made therein without departing from the spirit and scope of the invention, as set forth ,in the appended claims.

'I claim as my invention 1. A thermal relay comprising a movable shaft, a sleeve of conducting material disposed thereon and insulated therefrom, a plurality of spirally-wound bimetallic members disposed on the conducting sleeve, 2. contact member controlled by the movement of the shaft caused by the metallic members and an oil-containing vessel for enclosing the bimetallic member.

2. A thermal relay having a long time element in its operation for protecting an electrical apparatus comprising a plurality of spirally-wound bimetallic members incircuit with the apparatus, a movable shaft, 1 a sleeve of conducting material securely disposed on the shaft but insulated therefrom and having the inner ends of the bimetallic members secured to the sleeve, a contact containing vessel for enclosing the bimetallie members and serving to increase the thermal capacity thereof to cause the same to have a heating characteristic substantially in accordance with the heating characteristic of the apparatus to be protected. 3. A thermal relay for protecting an electrical apparatus comprising a bimetallic member traversed by the circuit current and immersed in oil to provide an increased heat-storage capacity to cause that member to have a heating characteristic substantially in accordance with the heating characteristic contact member controlled by the shaft, an

adjustable contact member adapted to be .engaged by the former contactmember, means cooperating with the bearing for adjusting said member, and means for causing the engagement and the disengagement of he contact members to be effected with a snap action.

5. A thermal relay comprising an opaque vessel adapted to contain a fluid having heatstorage qualities,- said vessel being provided with an opening serving as a Window, transparent means disposed behind said opening and arranged to co-operate' with the vessel to preclude the fluid from issuing through the window, a thermally-responsive member disposed in the fluid, a contact member controlled thereby, and an indicating scale disposed behind the window to indicate the position of the contact member.

6. A thermal relay comprising a fluid container,bearings disposed in the top and the bottom portions, a shaftdisposed between the bearings, a thermal element for controlling the shaft, 9. contact member to be controlled by the shaft and means whereby the position of the contact member may be adjusted by the upper bearing from the outside of the container.

7. A thermal relay comprising a fluid dontainer, bearings disposed in the top and the bottom portions, a contact member, means disposed between the bearings and operative to control the contact member and means disposed externally relative to the container and co-operating with one bearing for adjusting the contact member.

Y 8. The combination with a closed casing containing an operating element, of a bearing therefor extending through the casing, a contact member disposed in the casing and controlled by the operating'element and means externally disposed relative to the container and cooperating with the bearing to control the adjustment of the contact member.

In testimony whereof, I have hereunto .subscribed my name, this 15th day of February 1921. g

. BENJAMIN H. SMITH.

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