US1213937A - Electric-circuit breaker. - Google Patents

Description

S. F. NIELSSEN.

ELECTRIC CIRCUIT BREAKER.

APPLICATION FILED JULY 7. i914.

1 ,21 3,937. Patented Jan. 30, 1917.

2 SHEETSSHEET 1.

E uue mtoz wi/twwoca S. F. NIELSSEN.

ELECTRIC CIRCUIT BREAKER.

APPLICATION FILED JULY 1.1914.

'M 1 fid w attouuug STEFFEN F. NIELSSEN, 0F HOUSTON, TEXAS.

ELECTRIC-CIRCUIT BREAKER.

Specification of Letters Patent.

Application filed July 7, 1914. Serial No. 849,473.

To all whom it may concern:

Be it known that I, STEFFEN F. Nmnssnrr, a subject of the King of Denmark, residing at Houston, in the county of Harris and State of Texas, have invented certain new and useful Improvements in Electric-Circuit Breakers, of which the following is a specification.

This invention relates to improvements in electric circuit control apparatus, and more particularly to a circuit breaker which is adapted to automatically open the circuit when the conditions therein become abnormal.

It is well known to those skilled in the art that when starting an electric motor, it

often occurs that an undue amount of current passes through the windings thereof during the starting of the motor and until the same picks up speed. This is particularly true of single phase induction motors wherein the motor in a great many cases is started by simply throwing the main line switch, which immediately starts the motor with a full voltage thereon. This causes a rush of current into the windings of the mo tor and a consequent heating of the same, and if this were allowed to continue for a time, as would be the case if the motor was overloaded or did not pick up speed, the windings would probably burn out.

The object, therefore, of my invention is to overcome the above disadvantages and to provide a circuit breaker which will open the main line when a motor, induction or otherwise, fails to gather up speed in a predetermined time.

Another object of my invention is to provide a circuit breaker of the above class which is constructed of a minimum number of parts, is efiective in operation and is durable.

With the above and other objects in view my invention consists preferably in the construction, combination and arrangement of parts as set forth in the following specification and illustrated in the accompanying drawings, in which Figure 1 is a top plan view of a circuit breaker in which the preferred embodiment of my invention is illustrated. Fi 2 is a side elevation of the same, showing iagrammatically the windings and wiring or the circuit in which my invention is employed. Fig. 3 is a view similar to Fig. 2, showing the solenoid which I employ in section view,

also showing other portions of the device 1n section. Ifig. 4 is a detail perspective view of a gulde which is used in the preferred form of my invention. Fig. 5 is a detall perspective view of the catch.

S1m1lar reference characters indicate sim- 1lar parts throughout the various views of the drawings.

Referring more particularly to the draw- 1ngs the numerals 1 and 2 indicate the leads from the main line, and 3- indicates the wlndlngs of an induction or other type of motor, the class of motor being used having no bearing upon my invention.

In the preferred form of my invention I provide a solenoid 4 having the usual wind- 1ngs 5 thereon, the size of the wire used in these wlndlngs being determined by the class of work and the current which the same are intended to be used on. The windings 5 surround the tubular member 6, said tubular member 6 having a closed end 7 therein, the opposite end thereof being open, and a core 8 is adapted to be received and snugly fit within the tubular member 6, the members 6 and 8 being shown round in the drawings, but this is not necessary, as they may be any desired shape. A spring 9 is interposed between the lower end of the core 8 and the closed end 7 of the tubular. member 6, said spring 9 being of the expansive type, and tending to hold the core 8 in the position shown in Figs. 2 and 3. The purpose of the core 8 fitting snugly within the tubular member 6 is to provide a cushion or dash-pot, and the closed end 7 of the tubular member 6 is provided with a valve 10, said valve '10 being for the purpose of regulating the pressure of air or other fluid in the tubular member 6.

The upper face'of the core 8 is provided with a lateral extension 11, said lateral extension 11 being secured to the upper face of the core 8 by means of the screw 12, but while the member ll-has been shown as a separate piece it will be readily understood by those skilled in the art that the same may be made integrally with the core 8. A contact screw 11 is provided in the lateral extension 11 and disposed in a plane parallel with the plane of the core 8, for a purpose which will become apparent hereinafter. To prevent the rotation of the core 8 within the tubular member 6 I rovide a vertical standard or guide 13, sai guide 18 being secured by means of screws 1; to a plate 15,

Patented Jan. 30, 1917.

said plate 15 having the switch mechanism mounted thereon, which will be hereinafter more fully set forth. The guide 13 is provided with a longitudinally extending slot 16, said slot being shown to advantage in Figs. 3 and 4. A pin 17 or the like is adapted to be received within the slot 16 of the guide 13, said pin 17 being threaded into an opening in the-plate or lateral extension 11 upon the upper face of the core 8. TlllS construction prevents the rotation of the core 8 in the tubular member 6.

The switch element which I prefer to use consists preferably of a bar 18 fulcrumed at 19 to a vertical post or standard 20, said bar 18 is normally held in a horizontal plane by means of a catch 21 pivoted at on a vertical post or standard 23. The said catch 21 is provided with an arm 21", and said catch 21 is held normally in engagement with the free end 18 of the bar 18 by means of a spring 24 bearing upon the undersurface of the said arm 21, this feature belng shown to advantage in Figs. 2 and 3. A spring 25 is interposed between the end 26 of the bar 18 and the plate 15, said spring 25 being for the purpose of raising the bar 18 from a horizontal plane.

The contact element which I prefer to use consists of a plate 27 secured to the plate 15, and insulated therefrom by means of a washer or block 28, and has an upstanding projection 27 integral therewith. The arm 21' carries a block 29, said block 29 being secured to the bar 18 by means of a screw 30. To prevent undue corrosion of the blocks 27' and 29 when the circuit is broken the same may be made of carbon or any other suitable material which is adapted for this purpose. The plate 15 is preferably of non magnetic metal and one side of the circuit, namely, the lead 1 is electrically connected thereto as shown at 31. The standard 20 being preferably casted with the plate 15, and the bar 18 being mounted thereon, it will be readily seen that the bar 18 is in electrical connection with the lead 1. The plate 27 is electrically connected with one end of the winding of the solenoid 4 by means of the lead 32, said lead 32 being passed through an opening 15 in the plate 15 as shown in Fig. 3. The other end of the windings 5 of the solenoid 4 is connected with one end of the windings 3 of the motor or other electrical apparatus by means of the lead 33.

The starting switch of the motor is indi-' cated by the numeral 2" and may be of any desired type.

From the above it will be seen that the windings 5 of the solenoid 1 are in series with the windings 3 of the electrical apparatus, and that the switch bar 18 carrying the contacting members 27' and 29, is also in series with the solenoid 4 and the windings 3, of the electrical motor, and it will be readily appreciated that when the switch is opened, in the manner which will be hereinafter set forth, the windings 3 of the motor will be denergized thereby stopping the motor.

From the above description taken in connection with the accompanying drawings it is thought that a clear understanding of my invention can be had by those skilled in the art.

As has been hereinbefore set forth my invention is particularly applicable to be used in connection with single phase induction motors, these motors being in most cases started by simply throwing the main line switch. This in a great many cases causes an undue amount of current to be drawn into the motor, and as shown in the drawings the solenoid 4 being in series with the windings 3 of the induction or other type of motor receives the overload current and causes the core 8 to be drawn into the tubular member 6. At this time the core 8 performs a two-fold function, namely, provides a means for opening the switch arm 18 and also provides a plunger whereby to compress the air in the tubular member 6 and retard it and prevent rapid movement of the core 8 in the tubular member 6. The valve 10 is provided at the end of the tubular member 6 for the purpose of regulating the air pressure which is formed in the tubular member 6 when the core 8 is drawn into the same, thereby providing a means for regulating the speed with which the core 8 will be drawn into the tubular member 6 by virtue of the magnetic action of the solenoid 4. The spring 9 is for a like purpose in that it also prevents a rapid movement of the core 8 in the tubular member 6. It will be readily seen that when the core 8'is drawn into the tubular member 6 the air escapes between the wall of the tubular member 6 and the periphery of the core 8 which will gradually allow the core 8 to be drawn ontirely into the chamber 6. When the core 8 is drawn down to a predetermined position, the screw 11' secured in the lateral projection 11 willv contact with the arm 21 of the catch 21 forcing the same downward releasing the arm 18 and allowing the spring to break the circuit between the contact ele ments 27 and 29.

It willbe readily seen that by opening the valve 10 more or less will control the amount of air pressure in the chamber 6 and regulate the amount of time that it will take for the plunger 8 to reach the point that the trigger or catch 21 will be tripped. The function of the guide 16 will be readily appreciated when it is understood that the solenoid 4 is very apt to rotate slightly in the chamber 6 and therefore this guide has been provided so as to insure the movement of the core 8 in the same plane at all times,

thereby insuring the contactof the screw 11 with the arm 21 of the catch 21. If the motor picks up speed before the core 8 has been drawn the full distance into the chamber or tubular member 6, the current will return to normal allowing the core 8 to return to its normal position, but if the motor is overloaded or does not pick up speed the core 8 will be thrown into the chamber 6 and the same will perform the operation above set forth.

While my invention has been set forth as being particularly adapted to induction motors it will be readily understood that the same may be used in connection with street railway motors where conditions very similar to these exist, wherein the starting of a car has been done carelessly or the same is forced to run up a heavy grade, the insertion of this device in the motor circuit has been found to be a valuable protection against burning out of the motors.

lVhile I have shown a specific form of construction for my invention it will be readilyappreciated by those skilled in the art that certain changes may be made in the details of construction which shall not depart from the appended claims, but particular stress is laid upon the pneumatic means which is provided to retard the movement of the core, and also upon the guide which is provided for insuring the operation of the device.

Having thus described my invention, what I claim and desire to secure by Letters Patent is 1. A circuit breaker, including, in combination, a solenoid having a movable core, said core being snugly arranged within the solenoid to provide a pneumatic air cushioning chamber, means for controlling the air pressure therein, a slotted guide, a lateral extension carried by the free end of said core having means for engagement with a circuit opening device, and an arm extending from said core for engagement with said slotted guide to prevent rotation of the core when in use.

2. A circuit breaker, including, in combination, a solenoid having a movable core, said core being snugly arranged within the solenoid to provide a pneumatic cushioning chamber, a slotted guide, a lateral extension carried by the free end of said core carrying adjustable means for engagement with a circuit closing device, and an arm extending from said core for engagement with said slotted guide to prevent rotation of the core when in use.

3. A circuit breaker, including, in combination, a solenoid, having a movable core, said core being snugly received within the solenoid to provide a pneumatic alir cushioning chamber, a valve for controlling the air pressure therein, a slotted guide, a lateral extension carried by the free end of said core carrying an adjustable screw threaded shank for engagement with a circuit opening device, and an arm extending from said core for engagement with said slotted guide to prevent rotation of the core when in use.

In testimony whereof I aflix my signature in presence of two witnesses.

STEFFEN F. NIELSSEN.

Witnesses:

J. A. Ki'IBLER J. VAN DER Iimu'r.

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