Xutongyongfu XT-200 Portable AC/DC High-Voltage Withstand Tester for Electric Motors

Overview

The Xutongyongfu XT-200 Portable AC/DC High-Voltage Withstand Tester is an integrated high-potential (hi-pot) test system engineered for field and workshop verification of insulation integrity in medium- and high-voltage electric motors. Unlike conventional test setups requiring separate AC test transformers and DC high-voltage generators—each weighing over 100 kg—the XT-200 consolidates both AC dielectric withstand (power-frequency) and DC leakage current testing into a single, self-contained unit. Its design adheres to the fundamental principle of voltage stress application: applying controlled, calibrated high voltage across motor windings (phase-to-phase and phase-to-ground) while monitoring leakage current response and detecting breakdown thresholds. The instrument operates on the Coulombic charge accumulation model for DC testing and the capacitive-reactive load model for AC testing, enabling accurate assessment of insulation resistance, polarization index (PI), and dielectric absorption ratio (DAR)—key indicators of moisture ingress, aging, or contamination in stator windings.

Key Features

• Integrated dual-mode operation: Simultaneous capability for AC withstand (6–15 kV RMS) and DC withstand (10–25 kV) with identical ±1.5% output accuracy per IEC 61010-1 and GB/T 16927.1 calibration traceability.
• Compact architecture: Total mass of 22 kg enables one-person transport and deployment in confined switchgear rooms, turbine halls, or mobile maintenance vehicles—eliminating crane-assisted setup.
• Compensated reactive load handling: Includes a multi-tap, low-loss air-core compensation reactor (rated up to 550 mA capacitive current), allowing stable voltage regulation across motor capacitances from 0.05 µF to 2.5 µF—covering 3 kV to 13.8 kV class motors per IEEE Std 43-2013.
• Zero-position interlock and manual ramp control: Mechanical and electronic zero-start safety ensures no unintended voltage rise during setup; analog pointer meter provides real-time voltage/current feedback without digital latency.
• Robust protection suite: Dual-stage overcurrent cutoff (6.7 A primary-side trip), programmable timer-based disconnection (0–999 s, ±0.5% timing precision), and thermal overload monitoring compliant with Class H insulation duty cycles.
• Environmental resilience: Enclosure rated IP2X, conformal-coated PCBs, and humidity-resistant magnetic core materials ensure reliable operation at 90% RH and ambient temperatures from −15 °C to +50 °C.

Sample Compatibility & Compliance

The XT-200 is validated for routine acceptance and preventive maintenance testing of three-phase induction and synchronous motors rated up to 13.8 kV, including frame sizes from NEMA MG-1 200-series to IEC 60034-1 frame 355. It supports standard test configurations: winding-to-frame (ground), phase-to-phase, and inter-turn insulation evaluation when used with external partial discharge couplers. All electrical safety design elements—including creepage/clearance distances, enclosure dielectric strength, and grounding continuity—meet GB 50150–2006 (Electrical Installation Engineering: Acceptance Test Standards for Electrical Equipment), DL/T 596–2005 (Preventive Test Code for Power Equipment), and DL/T 848.2–2004 (General Technical Conditions for Power-Frequency High-Voltage Test Sets). Calibration certificates are traceable to CNAS-accredited laboratories under ISO/IEC 17025.

Software & Data Management

The XT-200 operates as a standalone analog-digital hybrid instrument with no embedded firmware or cloud connectivity. All test parameters—including applied voltage, measured leakage current, elapsed time, and pass/fail status—are recorded manually by technicians using standardized test report forms aligned with ISO 17025 documentation requirements. For laboratories requiring digital audit trails, optional external data loggers (e.g., Keysight 34972A with HV probe interface) may be connected via isolated BNC outputs. The device supports GLP-compliant record retention through its mechanical timer lockout feature and physical zero-start verification—ensuring procedural consistency across shift changes and operator rotations.

Applications

• Commissioning tests for new high-voltage motors prior to energization per IEEE 95-2015.
• Annual insulation condition monitoring in hydroelectric generator sets, compressor drives, and mine ventilation systems.
• Troubleshooting intermittent ground faults in aged motor windings using step-voltage DC ramp protocols.
• Verification of repair quality after rewinding or epoxy impregnation per NEMA MG-1 Part 30.
• Field validation of cable-to-motor termination integrity in offshore platform drive systems.
• Training and certification labs where reproducible, hands-on hi-pot methodology instruction is required.

FAQ

Does the XT-200 meet international standards such as IEC 61010 or ASTM D149?
It complies fully with GB 50150–2006 and DL/T series Chinese national standards, which are technically harmonized with IEC 60060-1 for voltage measurement uncertainty and IEC 61010-1 for safety. While not certified to ASTM D149 (dielectric breakdown of solid insulating materials), it satisfies motor-specific test requirements defined in IEEE Std 43 and IEC 60034-27-1.
Can it perform automatic ramp-and-hold sequences?
No—it is manually operated with analog voltage control and fixed timer settings. This design prioritizes operator situational awareness and eliminates software-related failure modes common in microprocessor-controlled testers.
Is the compensation reactor included in the base configuration?
Yes, the multi-tap air-core reactor (with labeled current compensation values per tap) is supplied as standard equipment, enabling immediate use across motor capacitances without auxiliary components.
What maintenance intervals are recommended for field calibration?
Annual verification against a certified HV reference divider (e.g., Tettex 7150) is advised. Internal potentiometer adjustment and insulation resistance checks should follow manufacturer-specified procedures in the technical manual.
How is grounding integrity verified before test initiation?
The unit incorporates a dedicated earth bond continuity check circuit (≤0.1 Ω threshold) that must be satisfied before the zero-start interlock releases—ensuring compliance with Clause 7.3 of DL/T 848.2–2004.