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OLTC.500A On-Load Tap-Changer Tester

The OLTC.500A is a precision tester designed to evaluate the on-load tap-changer (OLTC) of transformers — the only moving component directly connected to the transformer circuit. As required in the Procedures for Handling and Preventive Tests for Electrical Equipment, the OLTC must be checked for its action sequence and switching time to ensure safe and reliable operation.

The OLTC.500A performs detailed testing of:

  • Transition waveform

  • Transition time

  • Transient resistance value

  • Three-phase synchronization

This makes it an essential tool for transformer maintenance, diagnostics, and preventive testing.

Function

  • Measures transition waveform, time, and resistance of OLTCs

  • Evaluates three-phase synchronization during switching

  • Ensures OLTC reliability in transformer operation

  • Built-in precision acquisition system with 6 channels, high-speed sampling

  • Provides detailed diagnostic data for preventive maintenance

Technical Specifications

Working Environment Conditions

  • Ambient temperature: –10℃ to +40℃

  • Relative humidity: ≤80%

  • Altitude: ≤2000 m

Working Power Supply

  • Input voltage: Single-phase 220V (±10%)

  • Frequency: 50Hz ±1Hz

  • Waveform: Sine, distortion rate ≤2%

Output Test Power

  • AC output frequency: 50Hz ±0.2Hz (adjustable)

  • AC output voltage: Three-phase four-wire 0–500V (adjustable)

  • AC output capacity: Rated 1000VA

  • AC waveform distortion rate: ≤3%

  • Phase angle: 120°, phase difference ≤120° ±1°

  • DC current output: 0.5A, 1A (two levels selectable)

Instrument Test Accuracy

  • Synchronous acquisition channels: 6

  • Data accuracy: 16 bits

  • Acquisition speed: 200 k/s per channel

  • Cache depth: 8M byte FIFO

  • Voltage range: 0–500V

  • Current range: 0–100mA / 0–10A

  • Voltage & current accuracy: 0.5 level

  • Resistance range:

    • 0.5A range: 0–20Ω

    • 1A range: 0–10Ω

  • DC resistance accuracy: ±(5% + 0.1Ω)

Insulation Performance

  • Input-to-chassis insulation resistance: >20MΩ

  • Withstands AC 1500V insulation test (effective value)

Weight and Volume

  • Weight: 30 kg (excluding test leads)

  • Dimensions: 530 × 320 × 600 mm

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