Updated on 19 October, 2021
The Transformer Tester, also known as the MRC Transformer Tester, is a durable and affordable portable device used to do demagnetizing, discrimination, protection, phase, bias, and polarity checks on various types of electrical transformers. They are easy to use and provide a variety of test results that can help engineers make reliable and cost-effective electrical equipment purchasing decisions. This equipment helps engineers make accurate measurements for power, capacitance, inductance, and thermal expansion. These measurements and tests help them design and build new electrical equipment, troubleshoot existing equipment, and improve the performance of power supplies, circuit breakers, fuse holders, fuses, and breakers.
A transformer tester can be used in many different applications where it is necessary to measure one or more components of a system, such as motors, transformers, or transformers themselves. These versatile testing instruments have become invaluable tools in many fields. Engineers rely on them to help determine the condition of the primary and secondary metals in transformers. Qualified welders use them to diagnose and repair welding problems with their welds. Industrial manufacturers rely on them to ensure that transformers deliver power continuously and are safe for use. Those responsible for maintaining power lines and communications use them to check the integrity of the wiring.
A transformer tester must be carefully chosen for its specific job. There are several important factors that must be considered when choosing the right one for any application. It should be able to seamlessly measure the primary and secondary sides of transformers; measure capacitance and inductance; and easily disconnect and reconnect transformers without disrupting equipment. It must be fast to execute all required tasks and have a user-friendly interface to easily process input signals.
A useful Transformer Tester can perform all of the above tasks very quickly. The user can save precious time by conducting single-wire and multi-wire measurements. To test a large system, such as an electrical grid, the user should have a transformer with multiple inputs. Some useful features to look for in a fast and accurate test system include support for analog and digital outputs, easy measuring of the input resistance; support for input/output resistance multiples; support for multiple insulation thicknesses; support for industrial or commercial grade measurements; and support for different testing methods, such as resistive and thermographic measurement. The most reliable units allow for input and output voltage ranges in excess of 120 volts.
Other important measurements include input/output transient response, maximum and minimum forward voltage, as well as average forward and idle current. A transformer tester must also display an accurate percentage of efficiency in current operation. The higher the efficiency rating of the machine, the lower the cost of operating the machine. A transformer Tester must also be able to display an accurate measurement of THMs, which is a measure of both input and output power. This allows the operator to calculate the expected power levels of future equipment.
Measuring the efficiency of transformers is usually done on the primary side of the device. To do this, the operator places the primary end of the transformer over a load and measures the voltage across the terminals. Measuring the secondary side of the device requires that it be placed over the load. The operator measures the alternating current through the secondary winding of the transformer.
Many modern Transformer Testers now incorporate a digital LED indication for accurate testing and diagnostics. This feature provides for easy temperature detection, and accurate measurement and calibration of efficiency, peak power, and other important characteristics. Due to the low-cost of incorporating a high-performance but sensitive instrument such as a Scanner, many manufacturers have included an automatic thermal shutdown feature in their product offerings. There are two types of instrumentation used in this type of testing. One type of device performs the measurement while the other performs the test system verification.
An automatic thermal shutdown device performs the test by automatically cutting power to the unit when the temperature reaches a certain point. There are two main types of performance parameters measured with a Scanning Test Bench. The first type is the characteristic detection capability. This type of measurement is performed at regular intervals during the course of the transformer's operation. The second type of parameter measurement capability is the DC current capacity or initance rating. This test type uses a DC input protection diode and an output characteristic detector in combination with the Scanning Bench to measure the current flowing through the wires from the input terminals of the Transformer Tester to the output terminals of the bench.