Magnetic Amplifiers, Magnetic Reactors, Linear Reactors, Saturable Reactors, Control Modules, Mumbai, India

Magnetic Amplifiers And Reactors : MAP/ R

Magnetic Amplifiers And Reactors
Three-legged, saturable-core reactor. SECOND HALF CYCLE another approach to solving the problem of load flux affecting control flux is shown in figure. Figure shows a toroidal saturable-core reactor. The shape of these cores is a toroid (donut shape). The windings are wound around the cores so that the load flux aids the control flux in one core and opposes the control flux in the other core.
Magnetic Amplifiers And Reactors : MAP/ R
During the first half cycle, the flux aids in the left core and opposes in the right core, as shown in figure: view (A).
During the second half cycle, the flux opposes in the left core and aids in the right core, as shown in view (B).
Regardless of the amount of load flux or polarity of the load voltage, there is no net effect of load flux on control flux. Figure indicates Toroidal saturable-core reactor, FIRST HALF CYCLE.

For steady-state conditions, the voltage × time product applied to the magnetizing inductance, over a complete Cycle, must equal zero. volt × time product is V IN × D × Ts, where D is the on time duty cycle (D) and Ts is the switching period. The off period is defined as (1-D) × Ts. The voltage across the primary when the main switch is off is: V C – V IN . Where V C is the clamp voltage. Setting the equality:

V IN × D × Ts = (V C – V IN ) × (1-D) × Ts solving for V C = V IN /(1-D).


The Saturable Reactor consists of two core and coil assemblies each with two AC coils and two DC coils.

Two assemblies are required to avoid inducing AC voltage into the DC circuitry. The DC winding provides the ‘variable-saturation' of the cores and so forces the AC reactance of the assembly to change. It is made of M6 Grain Oriented Steel laminations/ or square B-H lamination as desired by the application and Nomex insulated copper windings. Together with the linear reactor the saturable reactor provides part of a variable voltage divider, which effectively slides the output voltage up and down, effectively providing voltage regulation.


The Linear Reactor is of a similar design to a single-phase transformer except that it only has one winding,

half on each limb. It is made of M6 Grain Oriented Steel laminations and Nomex insulated copper windings. The core has a number of carefully dimensioned gaps equally shared between the two core legs. The gaps are filled with Polyester-glass or Nomex insulation or both.

The reactance is maintained at a constant value over a large operating range. The ratio between the linear reactance and the reactance of the saturable reactor can thus be accurately determined and used to control the ‘voltage divider'


Control Modules

The plug-in controller module provides DC Chopper, the contol winding current may be controlled. There is one controller Per phase. The input voltage to the controller is a sample of the Voltage Regulator output voltage. It is sensed by a true - rms converter and compared with a stable reference voltage. The difference signal drives the Chopper driver, which provides phase fixed gate drive output.

The adjustment of this controller is limited to the output voltage adjustment potentiometer.


We will design these MAGAMPS for you, at whatever Maximum voltage drop across them. These will work exactly like two thyristors Back to Back, without the fear of loss of sync or current shoot-ups.

These will do lovely phase control for whatever application assuming non-capacitive loads.

These are called amplifiers because, small control current can control large load current.
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