Megger OTS100AF 100kV Auto Portable Oil Test Set Overview
The Megger OTS100AF 100kV Auto Portable Oil Test Set is a high-performance laboratory instrument engineered to provide accurate dielectric breakdown and withstand voltage testing of insulating liquids such as mineral, ester, and silicone oils. With its rugged build and advanced electronics, the OTS100AF ensures repeatable, reliable test results, making it a trusted choice for power utilities, industrial service providers, and research laboratories. The unit combines precision electrode alignment, intuitive operation, and compliance with the latest international standards to deliver confidence in every test.
Why Choose the Megger OTS100AF?
Monitoring and maintaining the quality of insulating oils is critical to the safe and reliable operation of transformers and other oil-filled electrical equipment. The OTS100AF is designed to meet these needs with exceptional accuracy and durability. Its moulded 400 ml test vessel is resistant to damage and contamination, while lock-in precision electrode adjustment wheels eliminate user error. The automatic test sequences and built-in memory allow seamless operation, making the OTS100AF both a robust laboratory tool and a future-proof investment.
What Sets the OTS AF Models Apart?
The OTS AF range (60 kV, 80 kV, and 100 kV) is designed with laboratories in mind. These models feature a larger test chamber for improved accessibility and ease of cleaning. The OTS100AF includes a 12-key alpha-numeric keypad for entering IDs, file names, and notes, simplifying asset management and reporting. For enhanced traceability, AF models also integrate with barcode scanners, allowing oil sample IDs to be logged directly into the system. This ensures smooth integration with LIMS workflows and reduces the risk of data entry errors.
▶ Video: Megger OTS Oil Testers Overview

Megger OTS100AF Key Features:
- Accurate dielectric breakdown and withstand voltage testing
- Full range of international test standards preloaded (IEC, ASTM, BS, etc.)
- Easy adjust – locking electrode gap wheels
- Fast, precise breakdown detection
- Ultra-fast (<10 µs) HV switch-off time for safety
- Laboratory-grade instrument with large chamber for easy access
- Bright 3.5” QVGA colour display
- Direct measurement of voltage and current via trip detection circuit
- USB connectivity for firmware updates and results transfer
- NEW – IEC60156-2018 compliance
- NEW – Viscous oil options (IEC60156-2018 V, Annex A, Annex A (V))
- NEW – Withstand test capability
Optimised Test Vessel and Preparation
The OTS100AF ships with a robust 400 ml vessel that complies with IEC and ASTM standards. Proper preparation of the vessel is essential for accurate results: rinse with the oil sample to avoid contamination, set the electrode gap precisely with the supplied gauges, and exclude moisture and air contact during testing. Optional 150 ml vessels are also available for low-volume applications, such as testing small transformers or CTs. Megger’s design ensures repeatable results even in demanding laboratory environments.
What Comes with the Megger OTS100AF?
- OTS100AF 100kV Auto laboratory oil test set
- 400 ml vessel assembly with stirrer lid fitted
- Internal impact printer
- Full IEC and ASTM electrode set
- IEC and ASTM impellers
- Electrode gauge set
- Calibration certificate
- PowerDB Lite software guide
- Quick Start Guide
- OTS Vessel Preparation Guide
Other Megger Oil Testers in the Range
Explore additional models in the Megger OTS range. Detailed specifications and data sheets are available in the technical resources section below:
❓ Frequently Asked Questions (FAQ)
Q1: What oils can the Megger OTS100AF test?
A. The OTS100AF is suitable for mineral, ester, silicone, and other insulating liquids. It is compliant with multiple international standards, ensuring accurate breakdown voltage testing across oil types.
Q2: How is the OTS100AF different from PB models?
A. PB models (60 kV and 80 kV) are more compact and portable, whereas the AF models, including the OTS100AF, feature a larger test chamber, alpha-numeric keypad, and barcode scanning options — ideal for laboratories that require high-volume, traceable testing.
Q3: What safety features does the OTS100AF include?
A. The instrument has dual redundant HV cut-off circuits and an ultra-fast HV switch-off time (<10 µs). The transparent lid is shielded for operator safety, and testing can be aborted instantly by pressing any key.
Q4: How should the test vessel be prepared?
A. Best practice is to rinse the vessel with the oil sample to be tested, avoid air bubbles during filling, and set the electrode gap using the supplied gauges. Megger recommends using separate vessels for different oil types to prevent contamination.
Q5: Can the OTS100AF integrate with data management systems?
A. Yes, the OTS100AF stores test data internally, transfers results via USB, and can integrate with LIMS using barcode scanning for sample identification. It also comes with PowerDB Lite software for asset and results management.