Product Overview

The HET 25kVA exciter transformer is engineered for precision high-voltage testing with dual-range outputs (20kV/10kV) and extended capability up to 60kV with water termination. Featuring ONAN cooling and advanced electrostatic shielding, it complies with IEC 60076-11 for demanding industrial applications.

Electrical Specifications

Advanced Protection Systems

1. Overvoltage Protection

• Piezoresistors on all HV outputs

• Zinc oxide arresters (25kA rating, IEC 60099-4)

• Ground-connected via Class 2 surge arresters

2. Insulation & Discharge Control

• 20kV corona-free HV bushings

• Electrostatic shield layer between HV windings

• Isovolumetric capacitance cores for stable voltage distribution

Mechanical Construction

Enclosure Features

• 12-gauge steel housing with ANSI 49 finish

• Heavy-duty wheel base (4× 250mm casters)

• Shell-type oil tank with 50L conservator

Terminal Configuration

• LV terminals: High-strength porcelain bushings

• HV terminals: Fiberglass-reinforced epoxy bushings

• Dual corona rings per HV bushing

Winding Technology

Advanced Insulation

• Cylinder-type winding with balanced capacitance

• Inter-turn insulation (2mm Nomex® layers)

• Electrostatic compensation shields

Dielectric Performance

• Impulse withstand: 200kV (1.2/50μs wave)

• Power frequency withstand: 45kV/min

• Partial discharge <5pC at 1.1Ur

Water Termination Testing

60kV Configuration

• Requires deionized water tank termination

• Minimum 2m clearance from ground

• Special 13.7kV tap input configuration

Safety Protocols

• Use Class 4 HV gloves during setup

• Verify water resistivity ≥5MΩ-cm

• Install grading rings on test object

Maintenance Schedule

Routine Service

• Monthly: Bushing visual inspection

• Quarterly: Oil dielectric strength test

• Annual: Winding resistance measurement

Critical Checks

• Verify arrester leakage current every 500 hours

• Monitor oil conservator level weekly

• Test ground continuity before each use