Power Glide Continuously Autovariable Transformer (Variac)

Power Glide is registered trade mark for AE make continuously variable voltage auto-transformer. It is the most effective device for stepless, breakless & continuous control of AC voltage & therefore for various parameters, dependent on AC voltage. The basic Power Glide is meant for operation from a nominal input voltage of 240V 1ph AC & can give output voltage anywhere between 0 to 240V or 0 to 270V AC by simple transformer action.

Three such Power Glides connected electrically in star and mechanically in tandem, become suitable for operation from a nominal input voltage of 415V 3Ph AC and can give output anywhere between 0 to 415V or 0 to 470V.

Standard Specification

Single Phase : Input 240 volts
Output 0 - 270 volts
Two Phase : Input 415 volts
Output 0 - 470 volts - in two phase
Three Phase : Input 415 volts
Output 0 - 470 volts - in three phase 50 Hz.

Two coils when connected in series and three coils when connected in star operated at tandem will give the desired output voltage.

To control the output voltage from remote point for various application in servo control automatic voltage stabilizers Power Glide is driven by step synchronous motor of lower speed instant reversibility and higher torque as per the application. The motor is coupled to the central shaft through necessary gears as per the requirement of output voltage. As the motor operates the central shaft rotates and the contact arm with the carbon brush slides along the ground surface. the motor operates on 240 V single - phase 50Hz AC. The rotation of the motor can be reversed by interchanging the motor connections by single pole double throw switch.

Special Features

  • Good voltage regulation and high efficiency.
  • Negligible waveform and power factor distortion.
  • Simple and easy to handle and smaller in size compare to ordinary.
  • Transformer of same capacity.
  • Rugged and compact mechanical construction.
  • Stepless continuous and smooth control of output voltage from zero to maximum range while on load condition.
  • Conforming to IS: 5142-1969.


  • Testing various electrical and measuring equipments.
  • To vary the speed of D.C. motor.
  • To control light in theatre auditoriums and studio.
  • In the manufacture of servo stabilizer.
  • To control temperature of various type of ovens.