FCMA Starters

FCMA
(Flux Compensated Magnetic Amplifier) Electrical Soft Starter are step-less voltage reducing starters. It ensure a
constant low starting current with incremental voltage and torque to the motor, to achieve a continuous and smooth
acceleration of the drive.
FCMA soft starters are air-core based series reactors, providing a complete starting solution for motor application
involving pumps, blowers, fans or compressors.

FCMA Principle

FCMA soft starters work on the principle of impedance control by superimposing two-phase opposed alternating fluxes on a common magnetic core. Controlled impedance, when connected in series with the motor, provides a constant current incremental voltage to the motor resulting in incremental torque as the motor speed increases.

FCMA soft starters controls the torque of the motor and it can be limited within 150 percent of full load torque. It also controls the amplitude of motor current without distorting the current waveform. This leads to zero harmonics

Methodology

FCMA consists of two windings wound on a common magnetic core:

• The first winding is known as the main winding and is connected in series with the motor winding.
• The second winding is known as the compensating winding and is wound with a polarity opposite to the main
  winding.

The second winding is excited with the counter electromotive force (emf) generated by the motor. The core is subjected to two simultaneous sinusoidal fluxes opposing each other due to the Magneto motive force (mmf) created by the main and compensating windings.

Flux compensation principle,

As both the fluxes are sinusoidal in nature, the net flux in the core is sinusoidal. Motor speed increases the
compensating flux increases, thus reducing the net flux in the core. The impedance of the main winding decreases
with motor speed, to keep the motor current constant. The voltage increment is obtained by correcting the natural drop in the motor current with speed

Applications:
FCMA soft starters are used in
i. Nuclear power plants for critical applications such as fuel moderator supply pumps.
ii. Large-scale pumping schemes required irrigation, drinking water supply, as well as sewage handling treatment.
iii. Complete starting solution for motor application involving
a. Pumps ( submersible, Vertical Turbine, Britefil pumps, Horizontal slip case pumps)
b. Induced Draught fan, Forced draught Fans, Chillers & Compressors.
c. Cane loader, Upsetter, Grinding & Ball mill, Shredder, Fibrizor, Cane & Jaw Crusher.

FCMA Specification Ranges:

Features of FCMA:

• No electronic components, Harmonic-free starting.
• Seismic qualification and harmonic-free operation to establish a purely sinusoidal waveform.

• Transformers and generators can be sized for running power and need not be larger for starting considerations.
• Energy conservation and restarting on power failure.
• Smooth starting with controlled torque minimizes impulse torques on rotating parts, increasing component life.
• FCMA soft starters used as replacement of auto-transformer starters.

References
1. Ms.Marathe Bhagyashree S, Prof. Khule S, “Design Of Solar Water Pumping System With FCMA Soft Starter.”
IEEE 2017 International Conference on Computing Methodologies and Communication (ICCMC), 2017.
2. Prafulla R.Deo, M.N.Gowaikar, “HARMONIC-FREE MAGNETIC (FCMA) soft starters for large capacity high
voltage induction and synchronous motors driving pumps and compressors.” the twenty-second international
pump users symposium, 2005.