Drive chokes

Choke or Reactors are of two types Input chokes or Line reactors and Output chokes or Load reactors . Both serve different purpose. Line reactors are also known as Input reactors which are used in the input side of the VFD where are Load reactors or Output reactors are used to protect the motor.

Input Chokes/Line Reactors/Input Reactors :

  • Input Chokes are used to protect the VFD from Input power line disturbances that leads to nuisance tripping of VFD and damages of VFD . Rather than protecting the VFD from line disturbances Input chokes also protects the Line from the harmonics generated from Harmonics . Magnetic and Controls line reactors are based on HP and voltage rating of the drive used.


  • Available at various Impedance level 3%,5.7%,14% or any other custom built
  • VFDs which are prone to disturbances like surge, spikes , transients are completely eliminated
  • Reduces Line notching
  • Designed to meet IEEE 519 standards
  • Terminals that minimizes the space
  • Vaccum impregnated
  • Protects motor from peak voltage and fast raise times
  • Extend semiconductor life
  • Attenuation of Line harmonics

Output Chokes :

Output chokes /Output reactors which are also known as Load reactors are used at the load side in front of the motor when the cable length is long . It is done mainly to protect the motor from capacitance of the cable length . The drives generates a high frequency PWM three phase output and noise spikes are generated on the leading edge of the signal . These noise signal gets amplified due to long cable length and additional capacitance of the cable . This results in high voltage in motor which results in insulation failure of the motor.

Magnetic and Controls are experts in designing of output chokes or load reactors irrespective of length of the cable . If the cable length increase more than 500ft Magnetic and Controls designs special dV/dT filters to protect the motor . Load reactors or Output chokes are connected in series between the controlled and the motor.


  • Available at different impedance 3%,5.7%,14% or any other custom built
  • Protects motor from long lead effects
  • Extends motor life
  • Reduce motor temperature
  • Reduce motor audible noise
  • Reduce output dV/dt
  • Designed to IEE 519 standards
  • Vaccum impregnated
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