Maximum performance
The maximum volume of water that the device can pump in a certain amount of time. It is one of the key specs of any pump because characterizes the volume of water with which the device can work. At the same time, it does not always make sense to pursue maximum performance — after all, it significantly affects the dimensions and weight of the unit.
Some formulas allow you to derive optimal performance values for different situations. So, if the pump is designed to supply water to water intake points, its minimum required performance should not be lower than the highest total flow rate; if desired, a margin of 20-30% can be added to this value. And for sewer models (see "Suitable for"), everything will depend on the volume of wastewater. More detailed recommendations for choosing a pump depending on performance can be found in special sources.
Maximum head
The maximum head generated by the pump. This parameter is most often indicated in meters, by the height of the water column that the unit can create — in other words, by the height to which it can supply water. You can estimate the pressure created by the pump using a simple formula: every 10 m of head corresponds to a pressure of 1 bar.
It is worth choosing a pump according to this parameter, taking into account the height to which it should supply water, as well as adjusting for losses and the need for pressure in the water supply. To do this, it is necessary to determine the difference in height between the water level and the highest point of water intake, add another 10 to 30 m to this figure (depending on the pressure that needs to be obtained in the water supply), and multiply the result by 1.1 — this will be the minimum pressure required.
Suction height
The largest difference between the height of the pump and the height of the water level at which the pump can provide normal suction. Without special devices, the maximum value of this parameter is 7-8 m — this is due to the physics of the process. However, when using an ejector (see below), the suction height can be increased several times.
Inlet hole size
The size of the thread designed to connect the pump to the suction line. This parameter is completely similar to the size of the outlet (see above) — in particular, it can be specified both for the nozzle and for the inlet of the pump.
Maximum power
Rated power of the pump motor. The more powerful the engine, the higher the performance of the unit, usually, the greater the pressure, suction height, etc. Of course, these parameters largely depend on other features (primarily the pump type, see above); but models similar in design can be compared in terms of power.
Note that high power, usually, increases the size, weight and cost of the pump, and also implies high costs of electricity or fuel (see "Power source"). Therefore, it is worth choosing a pump according to this parameter taking into account the specific situation; more detailed recommendations can be found in special sources.
Engine type
Type of motor installed in the electric pump (see "Power source").
— Asynchronous. The most common type of electric motor nowadays. Asynchronous motors are simple in design and inexpensive, while they are very reliable. Their main disadvantage is the difficulty in regulating the rotational speed and the dependence of this frequency on the load on the rotor; on the other hand, in most cases, these shortcomings are not critical.
— Synchronous. Without going into technical details, we can say that this type of electric motor is considered more advanced than asynchronous — in particular, due to the ability to adjust the speed easily. At the same time, such units are difficult to manufacture and expensive, so they are rare — mainly in high-end technology, where adjustment accuracy is a key parameter.
