Power Controllers :

Thyristor power regulators

At Theta Control, we take pride in being a leading provider of advanced thyristor power controllers in Pune. With a relentless commitment to innovation and excellence, we offer a comprehensive range of solutions to meet the diverse needs of industries requiring precision control over power systems. Our expertise extends to the realm of Thyristor DC Motor Controllers, ensuring optimal performance and efficiency for your industrial processes.

Power or voltage delivered to a load is controlled using Thyristor Power Controllers (SCR power controllers). Typical applications are found when power needs to be adjusted and converted into thermal energy. Thyristor power controllers are single-phase or three-phase alternating voltage devices. They vary the mains voltage for the load's activation time and are controlled by a controller.

The Thyristor Controller can reliably and consistently control the process according to the control signal. They offer a seamless method of adjusting the amount of power given to the load. Thyristors don't have any electromechanical movement, unlike contractors, which could result in arcing, sparking, and the creation of carbon. They increase the load's operational life by gradually supplying electricity to the load and preventing electrical surges and transients.

 Thyristor Operation Modes

There are three operating modes for thyristors. They include

•             Forward Blocking

•             Reverse Blocking

•             Forward Conducting


The thyristor is mainly used

•             In variable-speed motor drives

•             To control electrical applications requiring high power

•             Mainly used in AC motors, lights, welding equipment, etc.

•             In circuit breakers and fault current limiters

•             To control the speed of electric fans

•             In ignition switches for cars


•             Easy to control and requires less time to operate

•             Can control AC power and can handle large voltage/ current

•             Thyristor switches have a high operating frequency

•             When compared to mechanical switches, it requires less space

•             Can be used for heavy-duty operations

•             Thyristor maintenance costs are quite low

•             Extremely simple to use for complex controls

•             Thyristors only conduct current in one direction and can be coupled in parallel or series to give electronic           control  at high power levels

•             They can be used as oscillators in digital circuits

Options available in Phase Angle and Zero Cross control  

  • 4-Wire connection as standard ( 3-wire also available as an option )
  • Built-in protection with semiconductor fuses and snubber circuitry
  • Large Range: 1 phase - 10A to 80A & 3 phase 20A to 350A to meet  a variety of needs
  • Simple, Robust construction long-lasting reliability
  • Very High resolution with Extremely Fast response
  • Minimum maintenance with respect to contactors 
  • Elimination of RFI and Harmonics ( ZCO Range only )
  • Elimination of Arcing   Increased heater life due to lower temperature cycling  
  • Less noise and transients ( ZCO Range only )  
  • Compact size with similar footprint and volume as per comparable  contactor
  • 1 Phase or 3 Phase 3 Phase can have Delta / Star without Neutral
  • Available from 20A to 750A    
  • Optional current limiting available  
  • Compact size     
  • CE marking
  •  Soft Start (0-100 sec)    
  • Accurate Feedback Control    
  •  Supports Multi-Input Control signal    
  •  Heater Break Alarm Option available at 10 sec period    
  • Modbus RTU Protocol port with RS-485    
  • Supports Local or Remote Display    
  • 6 customizable digital Inputs.

Thyristor Switches for Capacitors

Thyristor Switches provide transient-free switching by eliminating inrush currents linked to electromechanical contactor switching. They also work without noise. The capacitors can withstand an infinite number of switching operations. Because of the seamless connection and disconnection, capacitor life increases the normal life.

Static switches with specific capacitors for power factor banks are used

  • To boost the equipment's useful life and power quality
  • There won't be a delay issue with an automatic power factor regulator meter and immediate power factor compensation
  • The power quality complies with the requirements specified by the more effective operation of power systems.
  • Switch for capacitors used in power factor correction    
  • The built-in control unit turns on/off at zero voltage - no surges
  • Operating voltage 380-480V AC, 3 phase Controller has protection for phase loss, fuse failure & overheating  
  • Small size, built-in fast-speed fuse for short-circuit protection
  • Compact size    
  • CE marking

1 Phase / 3 Phase SSRs

When an external voltage (AC or DC) is applied across the control terminals of a solid-state relay (SSR), the device turns on or off electronically. They perform the same task as an electromechanical relay but are more durable because solid-state electronics don't have any moving parts.

SSRs are made up of three parts:

  1. A sensor that responds to an appropriate input (control signal),
  2. An electronic switching device that changes power to the load circuitry, and
  3. And a coupling mechanism that allows the control signal to trigger the switch without mechanical parts.

They can be designed to switch either AC or DC loads. To switch currents up to about 100 amperes, packaged SSRs require power semiconductor components such as thyristors and transistors.

  • Wide range of ratings from 10A to 75A in both single and three Phase    
  • Multiple control options for 4-20mA and Voltage control    
  • Integrated Heat sink - Optional    
  • Random turn on, Zero Cross and Phase Angle controls  
  •  Screw and DIN rail mounting options