Selecting Current Transformers

Selecting Current Transformers There are a few decisions to be made when selecting current transformers: Type: opening (split-core) or non-opening (solid-core) Accuracy: monitoring or revenue grade Size: must be large enough to fit around the conductor being monitored Rated Amps Type In most cases, opening or split-core CTs are the preferred choice, because installation is […]

CT Opening vs. AWG

CT Opening Size vs. Conductor Size Overview How big of a CT window opening is needed to fit around a particular conductor diameter (gauge)? How big of a CT window opening is needed to handle a circuit rated for a particular current (amps)? This page covers recommended current transformer (CT) sizes for various conductor wire […]

Measurement Errors Due to CT Phase Shift

Measurement Errors Due to CT Phase Shift Overview Current transformers (CTs) exhibit two primary errors: Accuracy errors (related to gain or linearity) Phase angle errors Accuracy errors are fairly easy to understand. If a CT reads 0.5% low at 20 amps, then it would report 19.9 amps instead of 20 amps. Any measurements based on […]

CTS Series Split-Core Current Transformers

CTS Series Split-Core Current Transformers The CTS series CTs are available with windows from 0.75 inch up to 2.0 inch. They have a removable section, so that they can be installed without interrupting the circuit. Safe: burden resistor built-in, 333 mVac voltage output at rated full scale current, no shorting blocks needed Accuracy ±1% from [...]

ACTL-1250 Maximum Amps

The Accu-CT® ACTL-1250 (and ACT-1250) family of current transformers (CTs) have maximum amperage numbers as well as a rated amps associated with each model. This article explains these numbers. Rated Amps Also called “rated primary current”, this is the nominal full-scale current rating for the CT. At rated amps, the CT will output its nominal output voltage […]