Electric Reactors
of Russia & the CIS

A comparison of magnetically controlled shunt reactors and magnetic amplifiers

Primary principal diagrams:

Controllable reactor MCR Magnetic amplifier MA Fig.1 Fig. 2 2. Equivalent calculation diagrams Controllable reactor MCR Magnetic amplifier (?A) Fig. 3 Fig. 4

It can be seen from the equivalent calculation diagrams that with regard to the principle of action, the controllable reactor (MCR) and the magnetic amplifier (MA) are essentially identical. The differences lie in their respective application purposes and operational modes.

The MA is a controllable inductor connected in series with a load, and its aim is to regulate active and reactive power coming to the load. The MCR is a controllable inductor directly connected to an electric network, and its aim is to regulate reactive power coming to the controllable reactor itself.

Because the MCR is similar to an MA being run in load short-circuit mode, it seemed to many researchers from the beginning the 20th century that principles of the creation of the MA could be utilized for the manufacture of MCR. The author is aware of more than 100 inventions registered all over the world from the 1920s to the 1970s which attempted to create an MCR by improving upon the design of the MA. However, all attempts at creating controllable powerful inductive resistance failed to be competitive in the electrical engineering market. Common problems were high material costs, great power losses, and high current shape distortion during inductance regulation process.

In construction, almost all attempts were similar to conventional transformer and reactor hardware and were simple and convenient in operation.

But with the development of electrical networks, the need for powerful HV inductance with smooth (stepless) control continued to grow. At the end of the 1970s, the author received a number of orders for the development of bias controlled reactors (MCRs). To fulfill these, it was necessary first to revise the basic design concepts of the MA. The idea of "limited saturation" was put forward, a theory of limited saturation was developed for it (see ref. no. 3), and corresponding engineering methods and design principles were elaborated. After about a decade, efforts were successful. MCRs launched at certain factories of the former USSR MCR proved to be 2 to 3 times lighter than prototypes. It was possible to eliminate current shape distortions within 100 times the range of inductance regulation almost completely, and to increase the speed of regulation to the value of some parts of a network frequency period (see, for instance, ref. no. 5 and advertisement leaflets). Market analysis demonstrated their significant competitive position, at least in the CIS market.

The author has written about 50 publications on this topic and holds scores of related inventions. Acting patents for which he is the author and the patent holder are available. A list of some publications is attached.


  1. Briantsev A.M., Biktashev Sh. Sh., Lis I.D., Sokolov S.E. and others. Core-type controllable reactor with 3-D magnetic system in electric networks of 35-110 kV. "Electricheskiye stantsii", No.5, Energoizdat, 1982.
  2. Briantsev A.M., Brodovoy Ye.N., Gordyeev S.A., Leonov I.I. Method for correction of current shape of three-phase controllable ferromagnetic appliances. Izvestia vuzov "Electromehanika", no.6,1986
  3. Briantsev A.M. Biased ferromagnetic appliances with limited saturation of magnetic system sections. "Electrichestvo" , No.2, 1986.
  4. Briantsev A.M., Brodovoy Ye.N., Gordyeev S.A., Leonov I.I, Moszherin V.N., Solovyov G.P. and others. Magnetic and valve controllable reactor for static compensator of reactive power. "Electrotehnika", No.7, 1990. Energoatomizdat.
  5. Briantsev A.M. Basic equations and characteristics of magnetic and valve controllable reactors with strong saturation of magnetic circuit. "Electrotehnika", No.2, 1991. Energoatomizdat.
  6. Briantsev A.M., Beekey M.A., Leites L.V., Loorie A.I., Chizhevsky Yu.L. Electromagnetic processes in powerful controllable reactors. "Electrichestvo", No.6, 1994.
  7. Briantsev A.M., Biki M.A., Brodovoi Ye., Lurie A.I., Leites L.V. Elektromagnetic processes in high- power controlled reaktors. ZTR "Panorama" 1996, No.3, vol., p. 2-12