Rocker switch - a switch circuit device in which the contactors are controlled comfortable long handle, and the signal may flip between the outputs. It is present and a neutral position when the electrical connection is open. With the help of changeover of circuit breakers is possible to change the direction of rotation of three-phase motor.
general description
Rocker switch invented in the 80s of XIX century. number of exhibits from the museum Princeton even given.
Flip breakers often called switches. So is any switch that has more than two positions. There are two types of global: with protective cover and without. The cartoons and old reel of film is usually used last. The majority of circuit breakers contacts knife (see. picture). This ensures a reliable electrical connection with the comparative durability. Knife contactors are very popular in power circuits. For example, a similar construction is used in packet switches:
- To complete the circuit between the copper knives are spring contacts, tightly wraps the central conductor.
- Undocking occurs with partial force that eliminates the risk of accidental switching. At the same time contact is reliable.
- Copper blades rotated on a common axis.
- Wiring is connected to the spring contact bolts.
From the history
The first changeover switch
Patent Philip Langer under number US434151 A is the first example of circuit breaker. Especially the tumbler. Working in the company Vestengauza inventor knew of Tesla Motors, the first impression presented by the novelty is designed to switch the two-phase AC. In fact, the switch to reverse the meaning of the shaft of the commutator motor. Sort of a current of a large value is not available. As seen from the figure, it is a simple design.
Knives and contacts reveal a bizarre shape, which allows to capture the extreme position of the lever. The patent, issued August 12, 1890, one of the first changeover circuit breakers in history. According to unconfirmed reports, this type of devices has appeared in the 80s of XIX century.
The most remarkable part of the circuit breaker Philip Lange considered contacts, slanted corner on the handle position. This is done in order to simultaneously achieve the plates. It is better that while moving the knife initially hit a pole energized. While the inventor was trying to increase the resistance of the arc, breaking into two parts. Operating time was the fruit not fancy, but extracted in practice, hard work and numerous experiments.
early birds
The patent for the changeover switch published six months after application. Charles Perkins invented something worth attention. The Commission quickly missed patent number US650416 A, announced January 17, 1900. Charles posits own ideas:
- Ability circuit switching by the toggle handle.
- Clamping metal contacts from a single metal strip.
- Construction where both ends is worth a pair of contacts for circuit switching.
After the first birdie William Bossert publishes design spring-loaded rocker switch. Lever and the knife is no longer integrated. The operator, switching, removes the handle, while the springs. At a particular point latch jumps, sharp knife thrown click on another pair of contacts. There is a lock, securely fixing a new state of the device. Minimizing the possibility of arcing, which dramatically increases the operating current. William Bossert said patent December 10, 1901.
Contact intricate design. It consists of two identical arms, laid out like a penknife. The work is always only half, the other is inside the handle. Rotate the stops do not provide the hollow arm. Spring cocked between the two halves, shoulder flies, following the handle cranked operator. Similar designs have recently met in the industry.
Rocker switch Byrd Greybilla very simple and most suitable for school laboratories, rather than a high current switch. Contact nothing holds, except the weight of the handle and a coil spring, set in the central rack. Patent US803895 A 1905 is full mousetrap with cheese. Unlike - platoon latches is held in contact group - small tubercles copper, outside the grooves of the cylinder, the additional spring pushes.
One of the first designs consider the product presented in the patent US989362 A. Published in 1911 year, the document image comprises two rocker-switch pole (phase and neutral or two phases). Orin Hoeft says that invented something new and useful to convince the commission to solvency own idea. Figure of the patent presented on the screenshot:
- The entire device is mounted on an insulating base. And it looks like a mousetrap.
- Based on installed three pairs of spring contacts. The middle axle is fixed rotary knives fitted with a handle.
- Unlike current changeover circuit breakers knife voltage is always present, there is an input circuit.
- Two pairs of contactors at the edges of the voltage supplied to the output.
The author claims that the rocker switch is useful to humanity, and is one hundred percent right. At first glance, the design was flawed: the blades are connected to each other. On a nearby figure shows an image of the fastening strips, eliminating defects at all. So, in 1911, she was born the first changeover switch.
November 8, 1949 published patent US2487545 A, where one extreme terminal fuse replaced. This prototype of the modern circuit breaker, where instead of a manual circuit breaker should bimetallic relay. The figure shows the old mousetrap, but clearly visible fuse. In the disconnected position, the handle rests on them, the circuit is opened. Change - rotary axis is spaced farther from the base. Fuse on both sides provided with a flat copper knives are inserted in the axial displacement contacts and the terminal blocks.
Sophisticated XX century
Frank went much further Fix, whose patent number US1470717 A considered for four years: from 25 September 1919 to 16 October 1923. There is an amazing and unique - the first safe changeover switch. High voltage is actively used in science and technology. 20s - a time when the active development of electron tubes. And ten kilovolts is no surprise. Switch such a thing by hand is not the best idea - there arc.
The idea: a single-pole double-throw switch is hidden deep inside the housing, and the drive of the tribes and gears. When the control lever translation (shown - right) between the end stops translates voltage contactor. One terminal as in the previous case, zavedon axle. Unconditional minus scheme is the lack of shutter setting spring, accelerating the movement of the knife. The arc within the housing truly impressive at high voltages.
If you take the modern design of packet switches, they are limited to the size of the chamber and the air volume is clamped tight walls. When the ignition of the arc fibric cheeks pushed heated gases increase the pressure and extinguishing the flame. As you can see, a single-pole double-throw switch is not safe is designed for large currents or high voltages. While the patent states that the casing will protect the operator. A man with a successful scenario will not be affected, but the copper contacts will receive a good thrashing, when the voltage switches between circuits.
It is noteworthy that Frank Fix worked in Westinghouse Electric, knowingly dealt with alternating current (Westinghouse teamed up with Nikola Tesla - the father of multi-phase motors - the beginning of XX century). Based on the design claimed by the patent US1470717, it is presumably a device for lighting circuits. It is used at a time when the load is idle. Then, the current consumption is zero, the switching is performed without difficulty.
Such a switch is suitable for activating the backup circuit, while the bulk is undergoing renovations. The design could be used in the open space, which implies the expectation of private landlords. Today in the guard there, reversing circuit breakers for installation on the porch of the rear doors - not to confuse home. Conclusions are made for a simple reason: at the beginning of the XX century industrial engines were two-phase or three-phase. Pole in the picture at the main switch only. Consequently, it is a household appliance (e.g., heater), or lighting.
Zachehlonny first changeover switch, similar to the current model, apparently, invented German Hammerl. Pretty ingenious structure breaks contact in two places, which facilitates the arc quenching. Spring retainer arm in two positions, firmly holding mechanism of arbitrariness. US1799625 A patent issued April 7, 1931. The housing lid tightly covered, turning the handle to the side displayed. Rocker switch on the three phases is clearly designed for the industry - in the presence of three poles. By means of the device are likely to change scheduled engine speed.
As the rocker switch reverses motor
Reverse commutator motor by changing the direction of turn windings. Enough to provide current to the rotor opposite to achieve the desired result. Harder with asynchronous machines. Here you need to redirect to re-phase to the magnetic field rotates in the opposite direction. If prior to the switching sequence - A, B, C, and after - A, C, B. There are many other options.
A distinctive feature of the engine is considered to be a large consumption at the start. In particular, this applies to asynchronous. Cutout certainly biased or is obliged to discover the means to extinguish the arc.
Any product is characterized by the limiting value of the transmitted power, step over that it is not necessary. But arc generally provokes turbulent processes in the circuit. On induction motors, consuming 20 A per phase, have a high risk of arcing on contactors. For switching rational use of electromagnetic relays. Here the effort is much higher, in particular, the intercom system lock can withstand 200 kg and above in the gap. Simply break the fixture, rather than open the door.
Having said that, the switch irrationally used for switching high currents. And it is better to buy in the latter case with a good relay contactor.
