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Rotavolt Variable Auto Transformers

Rotavolt Variable Auto-Transformers

Rotavolt Variable Transformers

Rotavolt Variable Auto-Transformers provide a continuous linear regulation of AC voltage, with high efficiency and negligible waveform distortion. It offers a precise and effective method of controlling current, light, heat, motor speed and any parameter with a voltage factor.

Single and three phase models come in nine frame sizes and rating up to 60 kVA. Motorised versions available for remote or automatic operation.

View Datasheet and Dimensions

Key Features

  • Single and three phase versions come nine frame sizes, and ratings up to 60kVA


  • Maximum input voltage +6% of nominal, i.e. 240V models are continuously rated at 254V


  • Output voltage Continuously variable from 0 – 115% of input voltage


  • Load Power Factor. Any


  • Waveform distortion negligible


  • Environment –15 deg C to +45 deg C. For higher temperatures derate as shown.
    • 50 deg C 60 deg C 70 deg C
    0.93 0.77 0.59


  • Surge rating
    • Units up to2.5A (CO1 &CO2)  All Larger models
    6 times for 1 sec 10 times for 1 sec
    3 times for 1 min 3 times 1 min
    2 times for 5 mins 2 times 5 mins


  • Rated current this may be exceeded by 20% on parts of the track. Curves are available upon request


  • Mounting All models can be surface or panel mounted


  • Dimensions, the height dimensions quoted in the table always excludes the knob and shaft.


  • Fixing where the table indicates three fixing points, these are equally spaced by 120 deg. Alternate fixings provided on some models.


  • Low torque operation, ideal for high speed servo applications and multi ganged units


  • Rugged construction for safe portable use and to eliminate transit damage.


  • Enclosure, all models supplied in open form, ventilated covers to IP20 can be provided if required.


  • Motorised units available



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