Electromagnetic starters 220v, in their essence, are one of the varieties of contactors. Used for switching large loads. Their main purpose is to turn on, stop and reverse asynchronous three-phase motors.
What is the difference between contactors and starters?
The first and probably the most tangible is the size and weight. Since the contactor is a rather cumbersome thing, its weight is appropriate. The fact is that it is designed for switching very high loads.
The contactors use very powerful contact groups with arcing chambers, which also greatly increases the dimensions. But the same in terms of maximum operating current, the contactor and the starter will vary greatly in size.
Another moment immediately apparent - open contactors. For this reason, such equipment is installed exclusively in lockable closets or rooms, in order to avoid the entry of foreign objects and the ingress of moisture.
- 1 Application area
- 2 The principle of operation of the electromagnetic starter 220v
- 3 Types of electromagnetic starters
- 4 Types of fixtures
- 5 Versatile design
- 6 Thermal Circuit Breakers
- 7 Service
- 8 Briefly summarizing
Due to its simplicity and ease of installation, electromagnetic 220v actuators are widely used for control of various industrial and household equipment, such as machines, furnaces, systems ventilation. It can be all kinds of pumps and compressors, conveyor belts, cranes, lighting systems, escalators or banal elevators that we encounter every day. The scope of application is extremely wide - just do not list.
Electromagnetic starters 220v protect installation or machine from an erroneous launch. Turn off the equipment in case of power failure, which is very important in production to ensure safety (the so-called zero protection). Complete with a thermal relay, the device can protect the installation from abnormal overloads that can damage it or completely disable it.
The principle of operation of the electromagnetic starter 220v
At the base is an electromagnetic coil, which, when turned on, is energized and a metal core, with contact groups attached to it. In the majority of cases, the starter has two types of contacts: "main" - through which consumer switching, and “signaling” - for connecting low-power loads (indication or additional equipment management).
Types of electromagnetic starters
We are interested in electromagnetic starters with a supply voltage of 220V. Depending on the type connected through the equipment starter, its power and operating conditions, actuators of various types of performance and the maximum allowable current at the working contacts are used.
When choosing one or another option, first of all, you should pay attention to the operating conditions. Depending on them, you can There are three main groups:
- open (degree of protection IP 00) - used when installed in cabinets, panels and rooms protected from moisture, dust and foreign objects;
- protected (in the shell, degree of protection IP 40) - can be used in rooms with little dust;
- Dust - and - waterproof (in the shell, the degree of protection IP 54) - can be used both indoors and outdoors (subject to protection from direct sunlight and rain).
Types of fixtures
In addition, there is two types of starters Electromagnetic 220v:
- usual - when energizing the electromagnetic actuator, the electromagnet attracts a metal core with contacts attached to it. At the same time, normally closed contacts are opened, and normally open contacts are closed. When the power is turned off, the process goes in reverse;
- reversible - in their essence, are two ordinary electromagnetic starters on the same basis and having connections for blocking. This avoids the simultaneous activation of two starters.
According to the types of equipment connected with the help of an electromagnetic starter, there are three groups: AS-1, AS-3 or AS-4. They differ in the maximum allowable current of the main circuit and the type of connected load:
- AC-1 - inductive or low-active load;
- AC-3 - mode of direct start of electric motors with a squirrel-cage rotor, shutdown of a running engine;
- AC-4 - electric motor start-up with a short-circuited rotor, switching off and braking in countercurrent.
There are also options with a different number of “signal” contacts or the presence of a built-in thermal switch.
In simple electromagnetic starters 220v, signal contacts, as a rule, are used to organize "sticking". Thus, for example, after briefly pressing the “start” button, the actuator contacts will remain closed. In turn, in the case of even short-term loss of voltage in the circuit - contacts open and remain in this position, even after the restoration of power, until the button is pressed again.
In the case of electromagnetic reversing starters 220V, signal contacts are used to block the second starter, in order to avoid short circuits. A large number of signal contacts can be useful in the case of assembling more complex control systems (to example, with step-by-step loading or additional indication in circuits with remote control).
Also, it is possible to increase the number of contact groups using an additional block of contacts (contact prefix). It is mounted on top of an electromagnetic starter 220v, for which special runners with hooks are provided on the case of the latter.
Thermal Circuit Breakers
As for the thermal relay, as mentioned above, it is used in case of possible long-term equipment overload or insulation failure. In the circuit of such a relay, a bimetallic plate is installed, which opens the circuit when the operating current is long exceeded. Relay failure level adjustable within ± 15%. Therefore, it is worthwhile to estimate in advance the maximum allowable overload.
However, when using such constructions it is not recommended:
- installation at the top of the enclosure (the hottest air accumulates there);
- use in rooms (or their zones) with a large temperature difference;
- chassis operation experiencing strong vibrations or shocks. In particular, they do not recommend mounting together with electromagnetic equipment with an operating current of more than 150A, since during operation it produces quite strong shocks;
- Installation in places where the temperature can rise above 40 °.
There are nuances and with reverse units electromagnetic 220v. The fact is that they are mainly used for start, braking and reversing asynchronous electric motors. This operation is performed by applying a counter-current and is associated with a sharp increase in the load on the main contacts of the starter. In this regard, when choosing a reversible electromagnetic starter 220V, it is necessary to lay a stock of one and a half - two times in current.
It may be worth mentioning permanent magnet electromagnetic starters. They are designed for switching on by direct current and, if used in production, are usually connected via a rectifier.
As for the maintenance of the electromagnetic device 220v, in most cases, it is not required at all, until the last failure. The fact is that the working resource of the starter is calculated by the number of cycles of the closure - opening, and we are talking about hundreds of thousands of such cycles. Of course, we are talking about properly selected starters, operating in normal conditions.
But still, it is worth monitoring the condition of the fixtures. The fixing bolts must always be tight. Also, it is necessary to protect the actuator itself from moisture and dust. The service life of the contacts depends mainly on the operating mode of the starter and the switching load. Cleaning contacts, as a preventive measure, is not recommended. Most likely, it will only reduce the life of the device. Only in very rare cases, when detecting a strong melting of contacts, as a result of abnormal situations, can they be processed with a fine file.
After long-term operation of the starter electromagnetic 220v, may occur uncharacteristic buzzturning into bounce. In this case, you have to disassemble it. Dry the inside of the coil and core thoroughly with a dry cloth. Check the coil body for cracks and deformation.
When assembling - disassembling the starter, be sure to maintain the original position of the core and the coil (they are already lapped and reduce the buzz).
We considered the main types of electromagnetic devices 220v and the nuances associated with their installation and operation. Also the main advantages and disadvantages of certain types. Course in the process selection of switching equipmentshould proceed from the specific tasks and estimated estimates.
On the market there is a huge number of units with a variety of parameters, which will greatly simplify search for a solution to your problem, whether it is the inclusion of a separate electric motor or the automation of the whole enterprises.