Protection of electrical equipment

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.