Uninterruptible power supplies for pumps

In a private house, pumping equipment is used to ensure the operability of the heating system, water supply system. In the heating system, a circulation pump ensures the circulation of the coolant from the boiler through pipelines and radiators connected to them throughout the house.

In the absence of a centralized water supply, water is supplied to the house by pumping it out by a submersible or surface pump from a well or a well. That is, we can conclude that pumping equipment is an integral element of these communications of a private house.

Pumping equipment receives power from the electrical network, so in the event of a power outage the house will be left without the necessary communications for life: the coolant will not circulate through the heating system, and there will be no water in the tap. Moreover, the termination of the circulation of water (coolant) through the heating system will entail its excessive overheating in the vicinity of the boiler, which may lead to the failure of this boiler.

In order to avoid such situations, it is necessary to ensure autonomous operation of pumping equipment. This function is provided by uninterruptible power supplies for the pumping equipment of the heating and plumbing system of a private house.

Features of the choice of uninterruptible power supply for pumping equipment

When choosing an uninterruptible power supply for powering pumping equipment, several criteria are followed. First of all, this is the power consumption of the load, in this case pumps. Based on this criterion, UPS power selection.

In this case, one should take into account the peculiarity of the pumps, which consists in the fact that when they are started, the load current increases several times. According to the passport of pumping equipment, this characteristic is indicated as starting currentAs a rule, it is 4-7 times higher than the nominal. There are also pumps with a soft start function, which avoids current surges when starting the pump.

If the pump does not have a soft starter design, then when choosing Ups to supply it, it is necessary to take into account the maximum possible load current that will be at the time of starting this pump. If you select a UPS based solely on the load current in normal mode, then such a UPS may fail even when the pump equipment is first started.

It should be noted that the pumping equipment, like any electrical device, is designed for continuous and normal operation provided that the nominal parameters of the electrical network specified by the passport are observed, in particular, the magnitude and stability of the voltage. The UPS, regardless of type, protects the connected equipment, in this case the pump, from possible voltage surges.

There are three types of UPSs, each of which has a different operating principle.

The first type is Off-line UPS. Such a device has a built-in voltage relay that disconnects power from the mains and the UPS automatically switches to built-in rechargeable battery in case of undesirable differences.

The second type is Line-Interactive UPS. Such uninterruptible power supplies have a built-in voltage stabilizer, which protects the connected equipment from possible extremes, giving a voltage of a given value at the output. When voltage fluctuations occur, switching to offline mode does not occur.

The third type is UPS On-line type or Double conversion UPS. These devices are the most advanced and therefore the most expensive. The principle of their work is the double conversion of electricity.

Electricity coming from the network is first converted to direct current, used to charge the battery, and this current is immediately inverted to an alternating set value. That is, regardless of the magnitude of the input voltage, a sinusoidal voltage of a given value is output at the output of a UPS of this type.

In the event of voltage surges, such a UPS converts the incoming voltage to a predetermined value, without going into offline mode.

Thus, connecting the pump equipment through the UPS provides another advantage - extending the life of the pumps, as they will be protected from possible voltage surges in the mains.

It should be noted that any UPS has a range of operating voltages, and if Line-Interactive or On-line type UPSs are selected, this does not mean that such a power source will not switch to stand-alone battery power.

If there are voltage drops above or below the limits of the operating voltage of the UPS in the mains, it will switch to power from the built-in rechargeable battery, regardless of the type of UPS. This negatively affects the life of the UPS.

Therefore, when choosing a UPS should be guided by such a criterion as operating voltage range. The most optimal option is to choose a UPS with such a range of operating voltages at which the possible voltage drops characteristic of the section of the electrical network of a private house will not go beyond this range.

Another equally important criterion for choosing a UPS is choice of battery capacity. The battery capacity shows how long the pumping equipment will work in case of power from the UPS during a power outage.

In this case, it all depends on the duration of interruptions in the power supply of the house. If the interruptions in the power supply are short, then you can limit yourself to choosing the UPS with the appropriate power and capacity of the built-in battery, which is enough for several hours of battery life.

In the event that the interruptions in the power supply are longer, when choosing a UPS, you should pay attention to the possibility of connecting external batteries to the UPS, which will significantly extend the battery life of the pumping equipment.

For those cases where long interruptions in power supply are possible, up to several days, it is important use of generators (diesel, gasoline, gas) in conjunction with uninterruptible power supplies.

For example, in the event of a power outage, the pumps are powered by the UPS, the generator is periodically started, for example, for the possibility of using other household electrical appliances and the pumps are powered by it, at this time the UPS battery is charging. When the generator is turned off, the UPS battery will recharge and will continue to power the pump equipment.

UPS selection example for pumping equipment

Consider the example of choosing an uninterruptible power supply for the pumping equipment of the heating system of a private house.

According to the passport data, the power of the circulation pump is 200 watts, the multiplicity of the starting current is 4, respectively, the maximum power of the pump at the time of starting is 800 watts. Choose a UPS with a rated power of at least 800 watts. If you choose a device with a lower capacity, it may fail when the pump starts.

Voltage drops in the electric network reach +/- 8% of the nominal values. We choose an uninterruptible power supply that has a range of operating voltage within 220 V +/- 10%.

Such a UPS will not switch to autonomous operation in the event of voltage fluctuations in the network. In this case, in case of excessive voltage drops, the UPS will protect the pump equipment from possible damage by switching to stand-alone power from the built-in battery.

Electricity interruptions are short-lived, as a team of power engineers promptly eliminates the arising malfunctions of the electric network. Therefore, the task is to choose a device that will power the pumping equipment for several hours.

As a rule, the passport of any UPS indicates the battery life for various UPS loads, in this case we select a device with a suitable battery life. In the event that a UPS with an external battery is used, it is necessary to calculate the required battery capacity.

We give an example of calculation.

The pump power is 200 W, the operating voltage of the external battery is 12 V. We determine the load current with which the battery will be loaded, supplying a load of 200 watts. Dividing the power by voltage, we get the load current - 200/12 = 16.7 A.

The battery capacity is indicated in A * h - the product of the load in Amperes for the operating time in hours. That is, for the pump to work for two hours, it will be necessary to have a battery with a capacity of 16.7 * 2 = 33.4 A * h. We select the UPS with the closest capacity value of the built-in rechargeable battery, for example, 40 A * h. This value indicates that the battery, at a voltage of 12 V, can supply a load of 16.7 A for almost two and a half hours.

To calculate the operating time of the pump from a battery of known capacity, you can use the simplified formula - the capacity of the battery is multiplied by the value of its operating voltage and the resulting value is divided by the power of the connected load: 40 * 12/200 = 2.4 hours.

The calculation of the required battery power of the UPS is indicative for several reasons.

Firstly, this is the power consumption of the pumping equipment - it can be less or more than stated on the passport. Secondly, always the operating voltage of the battery is different from the rated values. And most importantly - the battery capacity may initially be lower than stated.

It should also be borne in mind that over time, during operation of the battery, its capacity decreases.

As for the type of UPS, in this case it all depends on the quality of the power supply at home. If the voltage is high-quality and does not require stabilization, then you can choose a cheaper Off-line type UPS. Also, this option is acceptable if the voltage regulator at the input is already installed in the house. home wiring.

In case of poor-quality power supply at home and the absence of a voltage stabilizer at the input, an On-line or Line-Interactive type of UPS should be preferred. This device will combine two devices - an uninterruptible power supply and a voltage regulator.

It should be noted that an uninterruptible power supply can be selected to power several pumps. For example, if there is no central water supply in a private house, then the UPS in this case will act as a backup source of power supply not only for the centrifugal pump of the heating system, but also for the surface and submersible pump, which pumps water from a well or a well.

In this case, it is impractical to choose a UPS to power two pumps simultaneously, since the pump for pumping water is turned on for a short period of time, as necessary. That is, it is possible to organize such a connection scheme for the pumps so that they do not work simultaneously in case of power from an uninterruptible power supply.

For example, when the house is de-energized, the UPS supplies the circulation pump for the heating system. If it becomes necessary to use water, a submersible (surface) pump is turned on, while the heating system circulation pump is disconnected from the electrical network.

It may be more convenient to install an individual uninterruptible power supply for each pump.In this case, it all depends on the number of pumps, their power consumption, as well as funds for the implementation of a technical solution.