Time cut-outs classify by current, by range of application and also by number of poles. They are one - two- and triple-pole. But inside they have almost identical device.
For emergency shutdown of the electric power in the house time cut-outs are used. Earlier fuse links which were very cheap, but disposable were applied. If the safety lock burns down, then it was necessary to establish or bug what is unsafe, or the new safety lock. The Odnorazovost is necessary to nobody today therefore over time began to use time cut-outs with might and main. The number of operations at them rather big. If on time, then life cycle can make both 10, and 20 years. Depending on that how often the switch will work.
Types of time cut-outs
Time cut-outs which had the same socle, as were originally popular with the simple glow lamp. They had two buttons. One big white which contacts, and the second small red became isolated (sometimes black), by which forcibly contacts were disconnected. Such time cut-outs do not give in to repair in spite of the fact that they understand. In case of breakage the replacement is made.
A bit later the time cut-outs of the VA series installed on DIN rail have become current. Simplicity of mounting, attractive exterior and also convenience, have allowed time cut-outs to win huge popularity both in life, and in the industry. They are used instead of simple lighting switches as life cycle at them huge, the body is absolutely safe, and it performs two functions – protective and the switch. In the industry time cut-outs for protection of engines are widely used. Their body is wider, and instead of one lever there are two buttons. On dimensions it we will proportion to three VA switches. It has three entrance and exit (three contact units). Is ideal for connection of the electric engine. All asynchronous machines become under three phases, they have three windings which connect in the scheme "star" or "triangle".
Device and classification
Time cut-outs have the similar device, in basis at them bimetal plate. At course of electric current it heats up. The bigger current proceeds, the heating is stronger. The size of working current depends on the sizes of this plate. At achievement of certain value of current there is excessive heating of bimetal plate. At the same time it is curved and forces contact unit to be opened. From here it is possible to see that time cut-outs are classified by current. And if more precisely, then in operation current size. Similar situation and at short circuit. In this case the circuit current increases indefinitely, there is instant heating of plate, it is curved, disconnecting contacts. And here is how long these contacts will be disconnected? The most part of designs of time cut-outs works instantly. But there are devices which work with delay. And the delay can be exposed by means of the special regulator. But at disconnection and short circuit of contacts the spark is formed. And it negatively affects metal, melting off it and leaving black raid. Therefore in design of the time cut-out there is arc extinguish chamber with grid. Thanks to it action of spark is weakened, deposit is not formed, and life cycle increases many times over.