Features and device of electromagnetic latches

 Features and device of electromagnetic latches

When doors are installed, it is assumed that they will close tightly. This task is assigned to the door locks. Important criteria for selecting the locking mechanism are its reliability and durability of operation. Electromagnetic latches meet these conditions.

They can be used on all types of door devices - on massive gates and gates, on entrance doors and those that are installed between rooms.

The principle of operation and design of the device

An electromagnetic lock is distinguished by its simplicity of design - its core is a core with a winding laid in a special case. The core is a large number of electrical steel sheets with a small magnetic action.Residual stress is reduced by paintwork.

The shape of the core is usually W-shaped. A winding is a simple coil on which a copper wire is wound. The conductor is covered with insulation.

The case of the device is often aluminum or steel. Occasionally there are plastic models, but they lose metal in reliability and durability.

The action of the product is based on electromagnetic laws. When current is applied, magnetic elements are triggered. Power of 5 W is enough for reliable fixation of doors weighing up to 150 kg.

Alternating current acts on the electromagnetic circuit, which is formed when the device is connected and disconnected. The charging process through the electric winding occurs with the assistance of a capacitor, as a result of which the polarity of the magnet changes. Remagnetization is produced by residual current.

The capacitor is one of the main elements of the EMR (electromagnetic latch). If it breaks, it is difficult to unlock the doors. Replacing a damaged part will help in this situation.

Types of devices

EMP can be divided into three parameters: the method of locking, the method of regulation and the option of attachment. According to the method of locking electromagnetic locks are divided into retaining and sliding.

  • Retaining. The principle of operation of the anchor mechanism - to break. Most often executed in the form of overhead models, but there are also mortise EME (unpopular due to the low rate of adhesion).
  • Sliding. The functioning of the locking mechanism is based on the shift of the armature. Mortise shears are usually found. Installation and installation of such devices requires the utmost care and accurate adherence to instructions.

    According to the method of control of the EMR also have significant differences.

    1. With Hall sensors. The product is made in the form of a chip, require additional power supply.
    2. With elements of reed switch. The control does not require a current supply. The closure of the device occurs with a magnet, while maintaining the desired voltage level.

      According to the mounting option, there are three types of devices.

      1. Overhead EMZ. Fixation is made by metal corners and does not depend on the location of the handle.
      2. Half-cut. The main part is hidden in the cavity of the door leaf, but some elements form a protrusion above the surface.
      3. Mortise electromagnetic latches are completely inside the door.

      Advantages and disadvantages

      Like all devices, electromagnetic locks have a number of advantages and disadvantages. Advantages of using EMP:

      • lack of noise during operation;
      • long service life;
      • can be combined with intercoms, code panels and similar devices;
      • the appearance of the device meets modern aesthetic requirements.


      • large size and weight of the product;
      • the supply of current (voltage) must correspond to the required level;
      • Once the hacked mechanism is very easy to open again.

      The dependence on the power supply can be attributed to the advantages and disadvantages of the device. In the absence of electric current EMZ opens. For fire safety, this is a plus in the event of a force majeure in a place where there is a large crowd of people, and to protect the premises from unauthorized entry - a minus.

      For this reason, when installing the EMZ they are connected to uninterruptible power supplies (UPS).

      How to choose EMZ

      When you purchase a device you need to pay attention to its main characteristics.

      1. Peel load. EMPs have a large holding force (unit of measure - kg).In the modern market, products with a load on the gap from 100 to 1000 kg and more are sold. For doors inside there are enough products with an indicator of 150 kg, for entrance wooden - more than 250 kg, and for metal door designs - from 1 ton.
      2. The magnitude of the residual magnetization. This indicator should be in the range of 1.5 - 3 kg, otherwise it will be difficult to open the doors (it will take a lot of effort). Usually the causes of the problem are errors in the process or incorrect selection of the magnet.

      You will learn more about electromagnetic locks from the video.

      Information provided for reference purposes. For construction issues, always consult a specialist.

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