Voltage calibrator UHV-905

currentimpedanceelectrical parameters

The UHV-905 is an automatic calibration system for current transformers (CT) and potential/voltage transformers (PT). It combines a unique advanced circuit with DSP technology to eliminate RC phase-shift instability and enables precise measurement of ratio error, phase/angle, impedance and admittance with automatic sampling and PC host support.

Main functions

• Automatic calibration for CT and PT: measurement of ratio error, impedance and admittance; timing/admittance testing.
• Unique advanced circuit combined with DSP to stabilize measurements against RC phase-shift instability.
• Large-format matrix LCD (320 × 240) with long-life backlight for clear display of ratio and angle differences.
• Automatic detection and indication of incorrect polarity and wrong transformer ratio.
• Host PC software for virtual instruments and remote control/visualization.
• Automatic range switching, S-level measurement handling and harmonic suppression > 40 dB.

Measurement ranges and operating conditions

• Operating environment: temperature 5℃ to 40℃; relative humidity <80% (at 25℃); altitude <2500 m; mains frequency 50 Hz ±0.5 Hz; mains input 220 V ±5%.
• Measurement ranges: cophase component 0.0001 ～ 200.0 (%) resolution 0.0001; orthogonal component 0.001 ～ 700.0 resolution 0.001; impedance 0.0001 ～ 20.0 Ω resolution 0.0001; admittance (ms) 0.0001 ～ 20.0 resolution 0.0001.
• Working current range: (1% ～ 149%) In (In = 5 A); (5% ～ 149%) In (In = 1 A).
• Working voltage range: (5% ～ 149%) Un (Un = 100 V, 150 V, 100 V/…); (5% ～ 149%) Un (Un = 100 V/3).
• Load (current): TX side < 0.12 Ω when cosφ = 1.
• Load (voltage): < 0.25 VA (100 V).
• Polarity error indication: when operating current/voltage > 5% of nominal and error > 180% a polarity indication is required; if > 10% of nominal and still no correct indication, this indicates a fault.
• Variable ratio error indication: when operating current/voltage > 5% of nominal and error between 30% and 180% a variable ratio error indication is shown.
• Insulation/withstand test: power socket and terminals withstand 1.5 kV to enclosure for 1 minute.

Features / Technical specifications

• Display: 320 × 240 dot matrix LCD with wide viewing area and long-life backlight.
• User interface: multilingual operation interface (original includes Chinese UI); large-font indicators for ratio and angle differences.
• Standards compliance: conforms to JJG314-1993 and JJG314-1994; supports automatic sampling.
• Advanced functions: automatic range switching, S-level measurement handling, harmonic suppression > 40 dB.
• Power consumption: <15 VA (without micro-printer); <25 VA (with micro-printer).
• Dimensions (L × W × H): 260 × 350 × 150 mm.
• Weight: 6 kg.