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Category: Motors

How to Test a Transformer

Transformers are everywhere in today's modern world. From powering your car speakers to an entire neighborhood, transformers are a wonder of the electrical industry. For professionals who work on these components, understanding troubleshooting techniques is paramount. Learn how to test a transformer by implementing a few strategies. A reliable, electrical circuit is the result of your efforts.

Sampling the Oil

One of the most traditional strategies for testing a transformer is taking an oil sample. Transformers will often be housed in a container full of oil. It creates an insulation system for the windings.

A technician might energize the power transformer, shut it off and remove a small sample. He or she takes the oil back to the lab for analysis.

Technicians check for conductive abilities, oxidation and dissolved solids. All of these clues tell the professionals something about the transformer. The reason behind this connection is the fact that every winding comes in contact with this oil. If there are any issues with the transformer, the oil will often tell the story.

Keep in mind that technicians may need to take several samples of the oil over a long period of time. These samples might indicate subtle decline and other features that can be missed with just one look at the liquid.

Checking Resistance

A transformer's purpose is to reduce or increase energy to a given system. However, there's still resistance involved along the transformer's windings that influences the amount of power moving through the component. An unusual drop or increase in resistance tells engineers if there's a system-wide issue.

For example, technicians can add a specific current to an isolation transformer in order to read the voltage drop. Current multiplied by the resistance is the voltage, so technicians can easily find the resistance that's natural for the component. Any poor readings tell them that there's a problem.

Part of how to test a transformer is understanding the basics of electronics. Resistance is present in every component. Calculating this amount takes a few minutes, and this fact can solve many issues when it comes to power conversion.

Curving the Current

Every winding, including those in a low voltage transformer, should respond in a certain way to applied current. Any skewed values read off of the windings could mean that they've been physically damaged. Their geometry is an important part of their functionality.

Technicians apply a voltage to a power transformer winding. With the component connected to a testing system, that voltage's current level turns into a plot line. Technicians observe the curve while testing a transformer. If an abnormal curve arises, that winding requires further service.

This testing strategy requires some background information before it can be properly completed, however. A baseline or normal value must be taken when the transformer is new. This information becomes a core tool when comparing it to the current seen right now. Technicians find the problem without spending too much time on each transformer.

Using Spectroscopy

When it comes to delicate components, you don't want to touch or move them very often. What is a transformer? It's simply windings connected together with an insulator around them. With this fact in mind, another testing strategy allows the transformer to be virtually untouched while technicians learn more about its anomalies.

Technicians use a spectrometer to "see" any moisture or matter within the insulator or oil. This test is different from oil sampling because there's no need to touch the insulator. A spectrometer reads the oil, and reports about the matter found inside the transformer.

The oil is under constant changes as temperatures and electrical power fluctuates. Spectroscopy tells the whole story about the transformer, which guides the technicians to a proper solution if a problem arises.

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