Types of current transformers and criteria for their selection

Transformers are used to convert current. With their help, you can separate power circuits from protective circuits, connect electricity meters in networks with high operating currents, if this is not possible directly, and also to perform other tasks. Transformers come in different types. Each of them has its own characteristics that should be taken into account when choosing.

Classification of current transformers

There are several classifications of current transformers . They take into account various factors, the main of which are the purpose and installation location, operating voltage.

Purpose

Depending on their purpose, devices are divided into transformers:

• for measuring;
• for guard;
• intermediate - for connecting measuring equipment in automatic protection circuits with the inclusion of a relay, for equalizing currents in circuits, etc.;
• used in laboratories - high-precision and with a large number of transformation ratios.

Operating voltage

Depending on the operating voltage, transformers are divided into devices:

• with a nominal value of over 1000 volts;
• rated up to 1000 volts.

Installation location

Depending on the installation features, transformers are divided into:

• installed outside;
• installed inside;
• overhead - placed on the bushing;
• portable - for testing in the laboratory and carrying out control measurements.

Criteria for selecting current transformers

When choosing a current transformer, several criteria must be taken into account. The main ones:

• secondary load power;
• primary current;
• rated operating voltage.

Secondary load power

This criterion is important to take into account when choosing a transformer. The buyer should ensure that the rated secondary power will exceed the rated secondary load.

Rated operating voltage

The nominal operating voltage in volts can be 0.66, 3, 6, 10, etc. The value must be equal to or greater than the rated value of the electrical installation for which the current transformer is purchased.

Primary current

This indicator must exceed the rated current of the electrical equipment for which the current transformer is selected. It is important to consider the overload capacity when purchasing.

Current transformers differ in purpose, operating voltage and other factors. Finding such devices will not be difficult in the Promindex service catalog . With its help, you can quickly select the desired transformer.