• Year
  • 1944 ?
  • Category
  • Power supply/conditioner or battery or charger 
  • Radiomuseum.org ID
  • 361337

 Technical Specifications

  • Main principle
  • Special principle (see notes)
  • Wave bands
  • - without
  • Power type and voltage
  • Alternating Current supply (AC) / 50 Hz, 190-260 Volt
  • Loudspeaker
  • - - No sound reproduction output.
  • Material
  • Metal case
  • from Radiomuseum.org
  • Model: Stabilistor - Westinghouse Brake and Saxby
  • Shape
  • Boatanchor (heavy military or commercial set >20 kg).
  • Notes
  • The Westinghouse Stabilistor was an advanced AC voltage stabiliser designed to deliver a stable, undistorted output voltage for single-phase 50 Hz applications, even under wide variations in input voltage (190–260 V) and load (no load to full load). Its design leverages magnetic saturation and a specialised filtering circuit to achieve high performance and reliability.

    Key Functional Components

    • Double-Wound Transformer:
      The double-wound transformer is central to the Stabilistor’s operation. It is designed to operate near magnetic saturation, allowing it to self-regulate the output voltage in response to input supply or load fluctuations. Working in conjunction with an autotransformer and interconnected windings forms a feedback mechanism that dynamically adjusts the core’s magnetic flux. This enables rapid compensation for voltage or load changes, maintaining output stability and minimising waveform distortion. The double-wound construction also helps suppress third-harmonic currents, especially when paired with the resonant filter circuit, ensuring the output remains sinusoidal and undistorted.
    • Autotransformer:
      Interconnected with the double-wound transformer, the autotransformer assists in voltage regulation and further enhances the system’s ability to respond quickly to load and supply variations.
    • Filter Circuit (Capacitor and Choke in Series):
      ​This filter is connected across the output and serves two purposes:
      • At 50 Hz, it acts as a capacitive load, drawing a leading current necessary for the stabilising action.
      • At 150 Hz (the third harmonic), it becomes resonant, providing a low-impedance path that effectively short-circuits third-harmonic magnetising currents, thus maintaining a pure sine wave output.

    Performance and Operational Characteristics

    • Voltage Stabilization:
      Guarantees output within ±2% for all loads and input voltages between 190 V and 260 V. Tighter regulation is possible if either the input or the load is held constant5.
    • Waveform Quality: 
      The output waveform remains virtually undistorted across the full load range, thanks to the harmonic suppression provided by the transformer/filter combination.
    • Response Time:
      The system responds almost instantaneously to changes in load or input voltage, making it suitable for sensitive equipment.
    • Efficiency:
      The Stabilistor achieves an efficiency of approximately 85%.
    • Power Factor:
      The input power factor is about 0.7 lagging at full output when supplying a unity power factor load. Loads with inherently low power factor should be corrected to maximise voltage stability and load capacity.
    • Frequency Sensitivity:
      Output voltage changes by about ±0.6% for every ±0.2 Hz deviation from the nominal 50 Hz supply frequency.
  • Literature/Schematics (1)
  • -- Original prospect or advert (The Engineer Jan 11, 1946, Pages 36,37.)
  • Author
  • Model page created by Gary Cowans. See "Data change" for further contributors.

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