Voltage relay: purpose, the principle of operation, device
Electrical engineering of our day is sensitive to mains voltage surges, so the lack of a fight against them can entail serious consequences for it. And, we will note, attracts all the time. Network providers are slow to upgrade their mossy power lines, substations and transformers, and the quality of the current in the networks is deteriorating every day. If industrial structures – where do they go? – are fighting this scourge by installing protective equipment at the entrance to their enterprises, then the “people’s” networks are often ownerless, and what kind of current jumps in them – in fact, no one knows. That is why, since there is little concern for citizens nowadays, they themselves should take care of themselves, protecting their personal power grids by means of a device called a voltage control relay, or simply a voltage relay. This is a device that will exclude the very possibility of overloads, and thus the breakdowns to which they lead.
What is a voltage monitoring relay? What is its purpose? How does a voltage relay work? What are the principles of its operation, structure and types? We will now give an answer to these questions, which always arise before those who are confronted by the situation with the need to purchase this device.
What the voltage relay protects from. Causes of network surges
There are various reasons for power surges. One of them is a break in a power line (for example, due to strong wind), the consequence of which is a real current shock to the equipment, leading to its burnout if it is not protected. Damage to the neutral wire can have the same consequences.
Another cause of power surges is the location of the transformer. With its location too far from the building, the level of current transmission may one-day “collapse”, and, clearly, this does not bode well for your technology.
The inclusion of a powerful device with a high level of energy consumption can also lead to voltage surges in the network. At the moment when this happens, the current in the second phase drops sharply. Devices that are in the first phase may become unusable or simply burn out from this.
All these problems are a real scourge of the power grid, and only a voltage relay can insure you against them.
Why and why do you need a voltage relay? What does a voltage relay do? What is the very principle of operation of a voltage relay? We will discuss this in detail below.
The principle of operation and the device of the voltage relay
The operation of the relay is ensured by the combined action of its two parts – electronic and power. The first monitors the voltage in the network and controls it, and the second, based on the data of the first, adjusts the load.
The heart of the voltage relay is a microprocessor that controls all of its operations. Its use today is considered necessary, since only thanks to it, the voltage regulation through the relay occurs smoothly.
The main criterion for the operation of the voltage relay is the speed of its operation: in order for the relay to effectively protect the equipment it protects, it must be very high. In modern relays, the response speed is determined by the specified settings and is set based on the conditions of use of the device.
The difference between a voltage relay and a stabilizer
The relay does not equalize the voltage, as the voltage regulator does, but simply de-energizes the load if the current parameters have exceeded the established limits of the rating. Therefore, the effectiveness of the relay is absolute: it is the protection of electrical appliances in its present and strict concept.
Scope of use of the relay
This scope is very wide because the voltage relay is used wherever it is necessary to protect electrical appliances from current overloads. Since electrical engineering is ubiquitous today, the accompanying relay can be placed in any room – of course, in compliance with all electrical safety standards.
The voltage relay protects any network, therefore there are single-phase and three-phase. The reasons for power surges are indifferent to him since it fights against any of them radically – by opening the network. The relay is extremely effective for the protection of devices with a large load on the electric motor, as well as devices with high inertia of operation in the transition to various operating modes. A number of electrical installations need voltage with rigid boundary parameters or full-phase – in this case, a voltage relay is also indispensable. In production, it ensures the uninterrupted operation of industrial equipment, in the life of offices and home life – it protects expensive and sensitive equipment from network surges. Variants of specific devices are determined by the place of their application: industrial relays belong to the class of group relays, the load current of which is high, and the installation is carried out only in the switchboard; individual relays, used in offices and homes of citizens and connected between the load and the outlet, can be installed by yourself, and a shield is not always needed for this.
Benefits of voltage relays
- The voltage relay has a lot of advantages. Reliably protecting electrical engineering from all sorts of surprises, it, moreover, has the widest range of applicability and in this sense belongs to the category of universal electrical devices. Here’s why it is good:
- The use of a relay eliminates the cost of repairing electrical equipment due to its breakdown from power surges in the network.
- The temperature range of its operation is from -20 to + 40 ° С, which means that it can be used not only indoors, but also outdoors – of course, in a sealed cabinet.
- The device is easy to install and does not need to be invited by a specialist – at least in the case of a socket-type relay.
- Relay models are aesthetic in appearance and do not violate the harmony of the interiors of the premises by their presence.
- The market offers tremendous opportunities for choosing the optimal relay option, both in terms of performance and price.
- How to choose a voltage monitoring relay for home and apartment
- Buying a voltage relay requires adherence to a number of simple rules. They are as follows:
- Buy the relay from a specialist store, where you will be given a real warranty on it. Be sure to familiarize yourself with it and read the relay instructions.
- To save money on buying relays, remember that the cheapest relays are socket-type, more expensive relays are extension ones, and the most expensive ones are DIN-rail-mounted. Our relays are cheaper than foreign ones; in addition, the price varies by brand, feature set and design. Buy a relay taking into account this and your real situation, but do not save too much: the mean pays twice.
- When planning the purchase of a single-phase relay, accurately calculate its power, taking into account the magnitude of the load it protects. For a three-phase relay, such calculations are superfluous, since they all have the same power.
- The best choice of a relay is a device with a display that shows the current value of the voltage in the network: the display will allow you to monitor this value not only for the relay but also for you.
- The material of the relay case must be non-flammable – polycarbonate is best suited for its role.
- Make sure that the relay has a thermal protection function – this will allow it to perform its tasks optimally.
- Top voltage relay manufacturers
- The issue of choosing a voltage relay is determined by a number of factors, of which we single out two: the ability to buy a voltage relay of good quality and at a reasonable price (without going beyond the budget segment) – and just buy the best relay, regardless of the contents of your wallet.
If we are talking about the first option, take a closer look at the rating of budget brands. Relays of the ZUBR and ADECS brands occupy the first positions in it by a large margin from the rest. These products will give you a long service life under normal use. Their cost ranges from 390 to 836 UAH, and the breadth of choice within these price ranges is sufficient for you to choose an option for yourself. As for the rating, not constrained by the budget, in 2020 its top was undividedly taken by the ZUBR brand relays: ZUBR D16, ZUBR D25t and ZUBR D32t.
According to the survey of the STROIMDOM construction portal, the places of the best relays in the 2020 rating were distributed as follows: ZUBR relay – 59.84%, Novatek-Electro relay – 10.66%, DigiTOP voltage relay – 8.20%, Adecs relay – 13.11%, Tessla voltage relay – 1.64%, Abb, Hager, Schneider – 5.74%; the share of the rest is insignificant. In our opinion, this picture is very subjective – in it, for example, the indicator of the domestic brand Tessla is underestimated, the reviews of which are good on the network. But we have no reason to doubt that the ZUBR voltage relay is really the best because everyone is writing about it.
It is released in Donetsk. It has a display that shows the dynamics of changes in the mains voltage in real-time. The error of its readings, measured by a high-precision Fluke 87 multimeter, does not exceed 2 V. The range of rated currents for which it is designed is 25, 32, 40, 50 and 63A; at a current rating of 63A, it can withstand 80 A for 10 minutes. The voltage at the upper limit is set in the range of 220 – 280 V, at
the lower limit – in the range of 120 – 210 V. The guarantee given by the manufacturer for this product is impressive – 5 years. Forum visitors write: in reality, it works much longer.