OTS PB vs OTS AF: Which Megger oil test set is right for you?

24 May 2025

Choosing an oil tester isn’t just about specs — it’s about workflow.

When you’re selecting an oil test set, it’s not only the technical features that matter. It’s how well the tester fits into your environment, supports your workflow, and keeps your team productive. The OTS PB and OTS AF are both powerful tools from Megger — but they’re built for different situations.

Let’s break down how to choose the right one for your needs.

Introducing OTS AF and OTS PB — Who They’re Built For

OTS PB

The OTS PB (Portable Breakdown) is designed for users who need flexibility and mobility.

It's ideal for field testing and mobile setups, especially when working across multiple substations or locations. Built tough for travel, it combines portability with the same high-quality results Megger is known for.

OTS AF

The OTS AF (Automatic Floor-standing) is purpose-built for high-throughput laboratories and permanent test bays.

It’s designed for volume—with features that support frequent and repeatable testing, reducing manual handling.

If you’re processing dozens of samples a day, this is your workhorse.

Comparing the Models

Let’s take a closer look at how they stack up in the areas that matter most.

Throughput

OTS AF: High-throughput performance with automated test sequences and minimal intervention. Ideal for busy labs.
OTS PB: Lower throughput by design — best for occasional or mobile testing needs.

Portability

OTS PB: Lightweight, compact, and easy to carry — especially the 60 kV model. Built-in lid and integrated handle.
OTS AF: Floor-standing, larger footprint, designed for a permanent setup.

User Interface

Both models feature intuitive touchscreen interfaces, but the AF offers more advanced automation and programmable options tailored for lab workflows.

Space & Environment

OTS PB: Fits in small vans, tight storage areas, and mobile environments.
OTS AF: Needs bench or floor space in a stable, controlled lab setting.

Compliance & Safety Features

Both units meet IEC and ASTM standards.
The OTS AF comes with enhanced lid interlocks and additional safety shielding suited for lab compliance.
OTS PB offers excellent safety for field conditions, with sealed test chambers and built-in discharge.

When OTS PB Makes Sense in the Lab

While the OTS AF is the go-to for labs, the OTS PB can still be a smart choice for lower-volume testing environments or labs with limited space and budget.

It’s also a great backup unit when your main test bay is in use — or down for maintenance.

Quick Comparison Table

Feature	OTS PB	OTS AF
Best for	Field work, mobile testing	High-throughput lab environments
Throughput	Low to medium	High
Portability	Lightweight and compact	Fixed installation
User Interface	Touchscreen	Advanced touchscreen & automation
Space Needed	Minimal	Requires floor or bench space
Compliance	IEC/ASTM	IEC/ASTM + enhanced lab safety

Making Your Choice

Whether you're running a high-volume lab or performing routine field tests, the right oil test set should support the way you work — not slow you down.

OTS PB and OTS AF are both excellent choices; however, the best one for you depends on your environment, volume, and workflow requirements.

And remember, it’s not just about specs — it’s about the kind of oil testing you do.