Overview of the multifunctional protection device UZM-50TSM

Electric networks in Russia do not differ in quality and stability. Power surges often lead to failure of electrical appliances and other electrical equipment. To protect against these problems, an instrument was invented called “voltage relay". One of the representatives of this category of devices is the multifunctional protection device UZM-50TSM, produced by the electrical company Meander. This review will help to find out what it is and why this protective device is needed, to understand its device and principle of operation, as well as to evaluate the advantages and disadvantages of the UZM-50CM.

Device and purpose

UZM-50TSM is a protective device whose main purpose is to protect an electric single-phase network (AC 230v) and equipment connected to it from the negative effects of sharp power surgescaused by various reasons (poor-quality or old equipment, the inclusion of powerful appliances or equipment with high inrush currents, a malfunction in the electrical network, improper connection and commissioning of equipment, etc.).

Appearance of UZM-50TSM

This device automatically turns off the power when registering a voltage deviation in the network, thereby protecting the wiring and electrical appliances from damage and fire. After the voltage is restored to normal values, the UZM-50CM automatically brings the network to a healthy state.

So, we list the main functions that UZM-50CM performs:

  • equipment shutdown when voltage goes beyond the set limits;
  • surge protection;
  • automatic inclusion after normalization of the power supply parameters, through a customizable delay time;
  • Decrease in starting currents when capacitive load is switched on by closing contacts at the moment the line voltage passes through zero (ZVS), which is especially important when using modern technology with switching power supplies;
  • the mode of measuring the voltage in the network consumed by the load of current or power, to switch modes during operation, press the "-" button and hold for 1 second.

The manufacturer warns that the protective relay does not replace other protective devices (circuit breakers, RCD and others), and works together with them in networks TT, TN-C, TN-S, TN-C-S.

Design UZM-50TSM

This type of device constructively consists of a built-in high power relay with a protective varistor. It is made in a case similar in size, type and installation method to a standard single-pole circuit breaker.

Dimensions UZM-50TSM

The terminals of the device are located in the front part and reliably fix the suitable and outgoing electric wires with a cross-section up to 25 square mm A wire has been drawn from the bottom of the device to connect to the zero bus and has a length of 0.5 meters.

Degree of protection for devices on a DIN rail

On the front panel there are adjustment and settings buttons (indicated by plus and minus symbols), an LED indicator that has two colors: green (for normal operation) and red (in case of an accident). There is also a yellow LED (relay) and an electronic display for monitoring the mains voltage (voltmeter) and displaying the operating mode.

Principle of operation

The operation manual fully describes all the details of the operation of the UZM-50CM device and it is important to familiarize yourself with it before installing and configuring the device. In this review, we briefly describe its main features.

After installation and connection, when power is supplied to the device, it automatically supplies voltage to the load after 10 seconds, while on its display there is a countdown and the “relay” indicator lights up and constantly lights up in yellow. On the electronic display, the protection device shows the current voltage in the network, and once every twenty seconds the letter U is displayed for one second and then the current voltage in the network is displayed. If for 1 second you hold down the “-” button and the device goes into the display mode of the next parameter - current, pressing it again will put the device into power display mode.

If you again hold “-” for 1 second (in the power display mode), the device will display the set level of the upper and lower levels of voltage, current and power, and if you hold it for 5 seconds, then the ultrasound transducer will switch to the “Setup” mode. Preservation of the set limits occurs automatically, or when switching to the installation mode of the next parameter by holding the “-” button for 5 seconds. Instructions for setting voltage thresholds are in the instruction manual, where the algorithm for working with the device, shown in the illustration below, is taken.

UZM-50TSM tuning algorithmWhen registering a voltage surge that differs from normal values, the device turns off and the red LED lights up, indicating an accident. In the event of an emergency, the electronic display keeps an indication of the current voltage in the network.

After the voltage is restored to normal (within the set threshold), the device restores the network, including power.

Advantages and disadvantages

This device compares favorably with its counterparts, making it a popular and indispensable protection device. These advantages include:

  • Compact sizes that allow you to easily mount the Meander UZM-50TSM protective device in small apartment electrical panels, which is what differs from UZM-50Ts.
  • Despite its small dimensions, this device still has a display for displaying and setting parameters.
  • UZM-50TSM has protection against surge surges and can be installed in private homes to protect against this phenomenon and prevent malfunctioning devices.

A significant drawback of this device is only in price, it is quite high. By the way, this drawback comes to naught when used, since repairing devices after power surges is much more expensive.


Main characteristics of UZM-50TSM:

  • rated current values: 63A;
  • current limit values ​​(within thirty minutes): 80A;
  • voltage thresholds adjustment: upper limit 240-290V, lower limit 100-190V;
  • upper voltage limit: 300V (20 ms);
  • lower voltage limit: 85V (100 ms);
  • functions for adjusting the threshold for exceeding power from 0.5 to 14.5 kW;
  • fixes the number of shutdowns and voltage values ​​in the device memory;
  • able to measure current parameters and voltage in the network;
  • climatic category according to GOST 15150-69: UHL2 or UHL4;
  • dimensions in width do not exceed 18 mm.

The review of this device does not include all its characteristics, a complete list and a description of its properties are indicated in the passport for this device.

Wiring diagram

Installation and connection of the protective device Meander UZM-50TSM is similar to any circuit breakers, which makes it very simple to install. The device is mounted and fixed on the din-rail. The connection is made by connecting the neutral wire to the neutral bus, the phase supply wire to the input of the device, and the load (group of machines) to the output terminal. The connection diagram is shown below.
Wiring diagram

UZM-50TSM and its analogues of the Meander company have similar technical characteristics, are made in accordance with GOST for protective devices, are available and popular among professional electricians for installation in residential and industrial buildings and have positive reviews. In order to protect your home network from overvoltage and the harmful effects of an unstable electric network, the use of UZM-50CM from Meander is a successful and correct solution, and this manufacturer guarantees the reliability and durability of its products.

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