May 2026 — Prom-nasos.com.ua

The issue of electrical protection of equipment remains relevant at all times. Despite the vast amount of information on this topic and the wide range of protective devices, monitoring and control equipment, electric motors still fail. Why does this happen? Most often, it is caused by the customer’s desire to save money on protection. Common justifications include statements such as: “Why do I need that control panel, everything works fine already,” “my old Soviet pump worked for 20 years without any problems,” “I turned it off because it keeps shutting down the pump and I have to go restart it,” and similar arguments. Here is an example of a typical “protection” setup for a 4 kW three-phase sewage pump. And here is the result of such “protection”! Another way to “burn out” your pump is to purchase a control box (protection and control panel) that supposedly has “everything included,” but fail to configure it according to your equipment parameters. Every device, including pumping equipment and control panels, must be operated in accordance with the requirements specified in the operating manual. As practice shows, the operating manual is often only read when there is nothing else left to read—or when everything has already burned out or seized. Here is another example of a “warranty case.” A borehole pump was connected through a protection and control panel , but no settings were configured. The pump has a power rating of 4 kW, 380 V, and a nominal current of 8.8–9 A. Considering a permissible deviation of 10%, the protection current should be set to around 10 A. However, the maximum protection current was set to 13.9 A. And the no-load current was 8.5 A. As a result, the pump was constantly shutting down during operation, since the no-load current was nearly equal to the nominal current, eventually leading to motor winding burnout. Do not neglect the requirements of the operating manual! Contact our company’s specialists. We will help not only select the right equipment but also configure it correctly.

Gear pump is a positive displacement pump. This means that the movement of the fluid (product) occurs due to a change in the volume of the working chamber. Accordingly, the operating principle leads to the following conclusion — the flow rate of such a pump must not be regulated by closing shut-off valves on the discharge line. When closing the valve on the discharge line, the following situations may occur: damage to the gears seal leakage coupling damage electric motor burnout In the images below, you can observe the current consumption when the pump operates with an open line (left image) and when attempting to close the valve (right image). When the valve is closed, the current immediately increases.

Cartridge seals are recommended for installation in pumps and mixers operating with such media as non-lubricating liquids, gases, liquids with a high concentration of solids, or those prone to crystallization, as well as adhesives, pastes, paints, and hazardous liquids. Installation of cartridge mechanical seals: Lubricate the shaft with a 2–3% aqueous solution of neutral liquid soap. Slide the cartridge along the shaft until the flange contacts the housing. Check the alignment of the seal on the shaft. Rotate the shaft by hand to detect any potential metal-to-metal noise. If the noise persists, check the shaft alignment. Connect the appropriate lines for flushing, circulation, and barrier fluid. This assembly requires a continuous supply of liquid, known as buffer or barrier fluid, into the chamber where the seal is installed. The pressure of the barrier fluid must be 0.5–2 bar higher than the pressure of the pumped (sealed) liquid. In case of seal failure, the barrier fluid will mix with the process liquid. This feature is especially important when the process liquid is hazardous or contaminating. In a double cartridge seal, connect an external fluid for cooling the secondary seal. In all cases, it is important to ensure that the process fluid contacts the seal before startup, as dry running can severely damage the sealing surfaces, even if it lasts only a short time. Although in some cases dry running cannot be avoided, special material combinations can be recommended to reduce its negative impact. If the seal is located in the oil chamber of a pump filled with biodegradable petroleum jelly oil, this oil (lubricant) remains in the chamber continuously until the next service replacement. There is no pressure in the chamber itself. In case of seal failure, the pumped liquid enters this chamber and mixes with the oil, which is detected by a water presence sensor (if installed). An additional leakage chamber (motor chamber) on the motor winding side is usually empty. If pumped liquid enters this chamber, it may damage the electric motor.