Servo Megik (A brand of Cosmo Electrical Instruments)

• A three-phase variable auto transformer is a device that allows smooth, continuous control of voltage in a three-phase electrical system.
• Unlike fixed transformers, it can adjust output voltage from 0 up to the input voltage (sometimes slightly above).
• It uses the auto transformer principle: a single winding per phase, with a movable contact (carbon brush) that taps different points on the winding.

⚙️ Construction & Working

• Three windings (one per phase), usually connected in star (Y) or delta (Δ).
• Movable brushes slide over the windings to vary the voltage.
• Compact design: Since it’s an auto transformer, it uses less copper and iron compared to a two-winding transformer.
• Voltage control: Stepless, precise, and efficient.

📊 Key Features

🏭 Applications

• Industrial testing: Provides variable voltage for equipment and machinery tests.
• Motor starting: Allows gradual voltage increase to reduce inrush current.
• Laboratories: For experiments requiring precise voltage control.
• Voltage regulation: Maintains stable supply for sensitive instruments.
• Power conditioning: Used in industries where voltage fluctuations must be controlled.

⚠️ Limitations

• No isolation: Input and output are electrically connected.
• Best for low ratios: Typically used when voltage ratio is less than 2:1.
• Brush wear: Mechanical parts (brushes) need maintenance.

👉 In short:
A Three-Phase Variable Auto Transformer is a versatile, efficient, and cost-effective voltage control device for three-phase systems, widely used in industrial and lab environments where precise voltage adjustment is required.

• A three-phase variable auto transformer is a device that allows smooth, continuous control of voltage in a three-phase electrical system.
• Unlike fixed transformers, it can adjust output voltage from 0 up to the input voltage (sometimes slightly above).
• It uses the auto transformer principle: a single winding per phase, with a movable contact (carbon brush) that taps different points on the winding.

⚙️ Construction & Working

• Three windings (one per phase), usually connected in star (Y) or delta (Δ).
• Movable brushes slide over the windings to vary the voltage.
• Compact design: Since it’s an auto transformer, it uses less copper and iron compared to a two-winding transformer.
• Voltage control: Stepless, precise, and efficient.

�� Key Features

�� Applications

• Industrial testing: Provides variable voltage for equipment and machinery tests.
• Motor starting: Allows gradual voltage increase to reduce inrush current.
• Laboratories: For experiments requiring precise voltage control.
• Voltage regulation: Maintains stable supply for sensitive instruments.
• Power conditioning: Used in industries where voltage fluctuations must be controlled.

⚠️ Limitations

• No isolation: Input and output are electrically connected.
• Best for low ratios: Typically used when voltage ratio is less than 2:1.
• Brush wear: Mechanical parts (brushes) need maintenance.

�� In short:
A Three-Phase Variable Auto Transformer is a versatile, efficient, and cost-effective voltage control device for three-phase systems, widely used in industrial and lab environments where precise voltage adjustment is required.

Varebal transformer 400 amp