Take the simplest example: you need to turn on the press 1 second after the operator simultaneously holds the two buttons in the pressed state. Thus, we guarantee that both hands of the operator are busy and give him time to monitor the readiness of the machine. The simplest solution is to connect the contacts of both buttons in series and put an electronic relay with a timer. If the timer allows adjustment of the delay time, then such a scheme will provide some flexibility of the system, but not too high.

Any additional conditions, for example, the requirement to control the sequence of button presses will put us in a difficult situation - we will be forced to change the circuit by introducing additional relays. This is not a difficult problem, provided that such a need arises extremely rarely. But in a competitive production environment, the time it takes for a new product to enter the market is crucial ...

The name of this electrical device for 0.4 kV electrical installations contains two fundamental actions: actuation as an electromagnet from the passage of electric current through the coil winding and start-up of the electric motor by power contacts.

Structurally, any magnetic starter consists of a stationary part and a movable armature that moves along the runners. It is highlighted in blue in the picture.

The starter can be very simplified as one button, on the case of which there are terminals with connected power circuits and stationary contacts. A contact bridge is mounted on the moving part. Its purpose: providing a double break in the power circuit to turn off the power of the electric motor and a reliable electrical connection of the incoming and outgoing wires when the circuit is switched on ...

The term "intermediate relays" most often means electromagnetic relays, which are used as so-called auxiliary relays, playing not the main, but very important role in the control circuits of various technological installations, machines, complexes.

Currently, the market offers a fairly wide range of intermediate relays. It is possible to select an intermediate relay both by price category and by the property of the tasks being solved. The most common production firms Finder, Phoenix, ABB, Schneider electric. From domestic, we indicate the relay type RPL, RPU-2M, RP, REP, for example. In a simplified form, the intermediate relay is an electromagnetic coil with a core that can be connected to either direct or alternating currentwhen voltage appears on which ...

Probably everyone saw the usual mechanical valve. It is enough in any courtyard of an apartment building to look at the heating main to see at least two gate valves at once.

Even without going into much of their design, and having no higher technical education, it is easy to understand that if you turn the handwheel, a shutter moves inside the pipe, which blocks the flow of water. It is precisely from this that such a mechanism of pipe stop valves “moves” and is called the “valve”. The device of a small mechanical valve is shown in the figure.

The use of such "manual" valves is justified only in those cases when the valve is used very rarely, from case to case, and their number is small. For example, block the pipeline section in the event of an accident. Well, a distribution pipe or riser flowed somewhere in the basement of the house ...