Main Terminal Boxes (MTB)

Main terminal boxes for generators are, simply put, the "way out" for the electrical power generated in the generator. Here, the energy is distributed and the electrical conditions are created that make our power grids behave as planned. Therefore, main terminal boxes are needed so that we can control and benefit from the electric energy created in the generator and, at the same time, ensure delivery over time with its equipment.


Main terminal boxes in various designs can be used for generators in all types of power generation facilities. Elektromontage can provide customer-specific solutions from 3.6 kV to 17.5 kV and with currents ranging from 300A to 4000A. We can provide according to both IEC and NEMA and also according to ATEX specific requirements.

Function and design

Main terminal boxes are used to lead the electrical power from the generator's outlet to the main power conductors in the power plant. It is also used to create a neutral point on the opposite side of the generator's stator windings. Main terminal boxes can be manufactured in different designs and the main functions can also be divided into two separate units if the generator design requires it.

Main terminal boxes can contain measuring equipment to monitor the production of the generated power, but also equipment for the generator's protection. These can be current and voltage transformers for relay protection, but also other types of measuring equipment, for example, for monitoring the generator's windings and protection functions for overvoltage and partial discharge. Of course, smaller junction boxes are also mounted on the sides of the main terminal boxes to easily link signals from the measuring equipment to superior protection and monitoring systems.