3 Frequently Asked Questions About CT meters

Many industries utilize current transformers, which are instruments used to monitor electrical output or current. These current transformers, or CTs, are used make sure the current output of industrial machines is at a safe and appropriate level.

Monitoring the accuracy of CTs is incredibly important, since their accuracy is necessary for both the safety of workers and to help the industry save money through reducing electricity use. In order to test that your CT is functioning properly, a CT meter must be used to conduct CT testing. To help provide you with more information about current transformer testing equipment, here are answers to three frequently asked questions about CT meters.

What Are CT Meters?

As stated before, a CT meter is an instrument used to determine the accuracy and functionality of a CT. Multiple tests are performed by the CT meter to evaluate the current transformer’s functionality, such as the ratio test, polarity test, and the excitation test. All of these tests are used to determine that the different characterizations of the CT, such as its knee point or primary to secondary current ratio, are equivalent to the manufacturer’s stated values. With a CT meter, a CT could enjoy a longer lifespan of up to 30 years.

What Are the Different Types of CT Meters?

CT meters are classified by their meter forms, which is a classification of numbers used by electricians and meter technicians to determine which meters should be used for each service. CT meters are used for transformer-rated services, and include meter forms 3s, 4s, 5s, and 9s. A Form 3s test meter is typically used for single-phase, two-wire services that only need one CT. Form 4s test meters are used for single-phase three-wire services, which use 2 CTs. Form 5s and 9s test meters can be used for several services but are most commonly used for the three-wire delta service and 4 wire wye service respectively. Choosing the right form for your CT meter is critical to accurately measure the output of your CT.

Where Are CT Meters Installed?

A current transformer meter can typically be found installed on services that are too large for self-contained meters, and utilize a current transformer. This usually means that the service provides greater than 200 amps of current. In comparison, household electrical service is generally provided as single-phase, 120 volt AC service, much lower than in many industries. Many buildings and industries that utilize such high amps include schools, hospitals and apartment complexes. If you work at or for such industries, it may be wise to invest in installing your own CT test meter.

Monitoring your building or company’s electrical current is necessary to improve both worker safety and monetary gain. Make sure to keep an eye on the CT monitoring your industry’s electricity usage by installing the right form of CT meter.