Load resistors

Category terminating resistors

Load resistors are devices used in secondary power supply circuits to minimize the errors of instrument transformers that occur when they are under low load. They are installed in close proximity to the meter. Installation in a separate switchboard is allowed, but in this case it is necessary to calculate the actual load that reaches the transformer as accurately as possible.

The design of preload resistors

The basis of the component of preload resistors manufactured by Priborenergo is a nichrome tape or a constant wire of various sections, depending on the required technical characteristics of a particular device. The body is made of sheet aluminum in five sizes (HxWxD, mm):
G108MF-RU - 57x80x162.25 (without radiators);
G108MFR*-RU - 77x80x162.25 (1 radiator);
G124-RU - 69x146x255 (without radiators);
G124R*-RU - 94x146x255 (1 radiator);
G124R2*-RU - 105x160x255 (2 radiators).
All presented resistor cases for additional loading of instrument transformers correspond to the IP65 protection class and reliably protect sensitive internal electronics from water and dust ingress. Therefore, if necessary, devices manufactured at the Priborenergo enterprise can be installed in outdoor switchboards.
Note! When selecting a high power preload resistor, it is important to take into account that their cases are additionally equipped with radiators that cannot be dismantled.

Model range of preload resistors "Priborenergo"

The product range of Priborenergo includes additional load resistors with a total power of 5 to 90 VA, which allows everyone to choose the optimal model for solving certain problems. In addition, the devices differ in the resistance value, which, depending on the model, can reach several thousand ohms.
To select the optimal load resistor, you should pay attention to the technical characteristics of the instrument transformer itself. First of all, it is necessary to take into account the value of the transformation ratio, the accuracy class, the rated power, how the connection scheme of the secondary circuits is implemented.
The optimal value of the transformer load is when it operates at 50% of the nominal value. In this case, a decrease to 25% is critical and can lead to a decrease in measurement accuracy. The same happens if the load is more than 100%.
Depending on where the additional load resistors are installed relative to the secondary power circuit, it is possible to adjust the operation of the measuring transformer within the limits specified in the technical data sheet of the device.

Why cooperation with Priborenergo is beneficial

Priborenergo is a direct manufacturer of preload resistors. Cooperation with the company has the following benefits:
Cost of equipment. All equipment presented on the site is sold with a minimum margin.
Support. If necessary, the company can develop a project and technical documentation for the implementation of its own solutions in your enterprise.
Quality.The production of equipment is carried out at our own facilities using high-precision CNC machines.
Guarantee. When buying a preload resistor on the Priboenergo website, you get an official 24-month warranty.
To get help in choosing a resistor, please contact the company's experts for a free consultation.