The permissible voltage deviation is one of the most important criteria in determining the quality of electricity and should not exceed ± 10% of 230 V in accordance with GOST 29322-2014. Voltage fluctuations adversely affect the operation of electrical appliances and can lead to their breakdown. To avoid this, various equipment is used, among which the UZM-51M surge protection device, manufactured by the Meander electrical company, compares favorably with its characteristics.
Content
Purpose and scope
UZM-51M (multifunctional protective device) is used to protect electrical equipment from power surges in single-phase electrical networks of any premises.
This device turns off the sources of consumption when the supply voltage increases or decreases, and also dampens its high-voltage impulse surges. The reasons for these deviations can be different:
- overload of transformer substations;
- inclusion of powerful asynchronous motors and welding machines;
- short circuit or breakage of the neutral wire;
- lightning strike into the power transmission line.
UZM-51M is usually used in household electrical networks, installing after the electric meter and circuit breaker at the power supply input to the room. It can also be used in three-phase networks.
Important. For full-fledged integrated security, the UZM-51M is installed together with other protective shutdown devices.
Principle of operation
Using the regulators installed on the device case, you can set the relay operation limit for the upper voltage from 240 V to 290 V and for the lower voltage from 210 V to 100 V.
When connected to the mains, the indication on the UZM-51M does not work during the first 5 s. A flashing green LED indicates that a voltage test is in progress. If it corresponds to the set parameters, the electromagnetic relay turns on, and this is signaled by the uniform glow of the yellow and green LEDs.
Reference. You can speed up the start of the protective device by pressing the "Test" button.
In normal operation, the UZM-51M controller constantly monitors the voltage value, and the varistor dampens its pulses to an acceptable value.
The operation of the light indication differs in various emergency modes.
A flashing red indicator warns that the voltage has significantly exceeded the norm.
If the yellow LED is off and the red LED is on continuously, it means that the voltage has exceeded the set value and the relay has disconnected the load.
A flashing green indicator light indicates that the reclosing time has started.
The green and yellow LEDs, lit constantly, signal that the voltage has completely returned to normal and the relay is turned on.
Attention. The restart time can only be set to 10 seconds and 6 minutes.
If the green LED on the panel starts flashing while the yellow LED is constantly on, it means that the input voltage has greatly decreased.
The flashing lower indicator, which has changed from green to red, signals that the countdown of the electromagnetic relay off time has begun.
A red LED flashing at a frequency of two seconds and an extinguished yellow one indicate that the relay is turned off.
When the voltage is normalized, the alarm works, as in the first case.
Alternately flashing red and green light remind you to start the device by pressing the test button again.
Appearance and design
UZM-51M, like other modular devices, is mounted on a standard DIN rail. The relay housing is plastic, with two upper and two lower tunnel-type terminals.
On the front of the panel there are two rotary regulators that set the maximum and minimum voltage limits for the relay to operate, two transparent eyes and a “Test” button between them.
The glow of the lower eye in red means that the emergency mode is on. Glow green indicates that everything is normal. If the upper peephole glows yellow, then the contacts of the electromagnetic relay are closed.
The test button not only turns the device on and off, but it also sets the re-start time.
Inside the case are an electromagnetic relay, a microcontroller and a varistor. The relay contacts break the phase wire, and the zero bus passes directly through the housing.
Main technical characteristics and dimensions
- UZM-51M operates at a nominal voltage of 220 V with a frequency of 50 Hz;
- maximum voltage - 440V with a frequency of 50 Hz;
- rated current - 63 A;
- maximum current - 80A;
- rated load power - 15.7 kW;
- maximum power - 20 kW;
- maximum absorption energy - 200 J;
- when the voltage rises, the shutdown threshold can be changed from 240 V to 290 V;
- when the voltage drops, you can change from 100 V to 210 V;
- deviation of threshold values is not more than 3%;
- impulse protection works in less than 25 ns;
- it is possible to switch the reclosing time from 10 s to 6 min;
- operating temperature from -25°С to +55°С;
- overall dimensions - 83x35x67 mm;
- weight - 140 gr;
- service life of at least 10 years.
Wiring diagrams
Figure 1 shows a typical UZM-51M connection diagram.
On Fig. 2 shows a diagram that allows the connection of a neutral wire only on one side, which makes it possible to combine zero terminals on one common terminal block.
On Fig. 3 shows a circuit that allows you to disconnect the load with an additional switch.
Pros and cons of the device
The positives include:
- low price in relation to quality and service life;
- the ability to independently adjust the threshold voltage;
- small dimensions (occupies two modular places in the shield);
- little resistance;
- little weight;
- simplicity and reliability of connection.
There are practically no disadvantages. It is desirable to have a display.
Analogs UZM-51M
The industry produces a large number of devices similar in purpose to the UZM-51M. The most popular ones are: PH-111; DigiTop; Zubr.
comparison table
| Voltage relay brand | UZM-51M | PH-111 | DigiTop | Zubr |
|---|---|---|---|---|
| Rated current, A | 63 | 16 | 63 | 63 |
| Upper voltage limit, V | 290 | 280 | 270 | 280 |
| Lower voltage limit, V | 100 | 160 | 120 | 120 |
| Response time, s | 0,02 | 0,1 | 0,02 | 0,05 |
| Place in the panel, number of modules | 2 | 2 | 3 | 3 |
| Reclosing time, s | 10 or 360 | 5 to 900 | 5 to 900 | 3 to 600 |
| On-screen voltage level indication | No | No | Yes | Yes |
As you can see, the UZM-51M multifunctional protection device is not inferior in its parameters to other devices of this type, and according to user reviews, it has proven its reliability by the test of time.
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