Timer timer (RV) is an electrical device designed to create a time delay. Depending on the selected group of contacts (normally closed or normally open), it can turn on or off certain consumers for a certain time.
There are several types of time relays with different time ranges, purpose, device and principle of operation. In the article we will talk about all their types and help you decide which type of time relay to choose for specific tasks.
Intermediate relays
Intermediate timers relays are necessary to create a time delay in the mechanisms. For example, when starting the engine, it consumes current 7-10 times more than the nominal, which leads to the operation of the current relay. Tidying up the current relay is not an option, because if a problem arises with the motor, it may fail.
To solve this problem, the current relays are shunted using a time relay, so that at the time of start the starter does not lose power due to the current relay and returns to normal operation, after which the time relay stops shunting the current relay, and if there are problems with the motor will still be protected. For this purpose, a relay with an anchor or clockwork mechanism is used. The principle of operation is the same as that of a watch. The electromagnet starts the clockwork, and after the time has passed, the relay performs its function (depending on the group of contacts). The limits of operation of such relays are from 0.1 to 20 seconds.
Pneumatic relays
Pneumatic relays are not suitable for the previously described situation, but they can cope with tasks that require cyclicality. The principle of operation is such that there is a chamber in which there is an opening and a piston with an anchor. When a signal is received, the electromagnet pulls the anchor, and depending on the set time, the diameter of the hole changes, respectively, and the speed of filling / emptying the chamber with air. This sets the time delay. Delay limits up to 60 sec.
Electromagnetic relays
Electromagnetic time relays (timer) are applicable in direct current circuits, but are practically not used in everyday life. The only example for domestic use is the creation of an emergency lamp, which is based on this relay itself. The mechanism is such that there is one short-circuited coil on the electromagnetic coil, which, due to the residual magnetic field, keeps the mechanism from going into a normal state. The delay limits are only 5 seconds.
Electronic relays
Electronic timers relays have wide limits of regulation, and their work is based on natural processes, such as charge-discharge capacitor, which begins to count in seconds.
These very processes drive the whole mechanism. Applications they can have a lot, due to the wide range of regulation of the time interval. But the price of such devices bites, and they are suitable for a single time setting. In fact, electronic PBs are morally obsolete, and they have already been replaced by microprocessor relays with a programmable time delay setting, on / off periods, that is, you can actually set a schedule for when, how much, how much to turn on the consumer. These timers are called cyclic.
Cyclic relays
Cyclical timers (programmable timer) enable or disable the consumer at a specific time and for a certain period of time. The work is based on microprocessor technology and electronics. They find their application both in everyday life and in production. In everyday life, this is rather not a time relay, but a cyclic timer that turns on and off, for example, the illumination of an aquarium, terrarium, street lighting. Having set the program, it can be established that the aquarium illumination should turn on at 19:00 and turn off at 06:00. The use of the device in everyday life is very different. And its price, first of all, depends on the accuracy, as well as the power that it can turn on and off.
Having the most basic knowledge of electrical engineering, it is possible to expand the limits of a household timer for a power relay. By purchasing a magnetic starter and including the coil contacts through a time relay, and the power contacts in the network, our starter will be included in those time intervals that we set on the household timer. And the power is now limited not by a timer, but by a starter.
By purchasing the cheapest timer and starter, for example, PME 111, we will increase the maximum current to 10 A, including timers and timers in the socket, which is already good. Such schemes are useful when, for example, there is a large capacity that takes a long time to fill. Having assembled such a circuit, you can once notice the time of filling the tank and turn on the pump through this simple circuit. And so with any consumer.