Current transformer hook up

  • The importance of current transformers (CT) in today’s solar installs
  • The Correct Way to Specify and Install Current Transformers
  • Safety Tip: Current Transformer
  • Transducer Wiring 101
  • CT Installation and Wiring
  • Current transformer hook up
  • 3 Phase Current Transformer Wiring Diagram

Current transformers, or CTs, are transformers used to step down the current level of high-power transmission systems to measure or monitor the current levels. CTs are required because standard current measuring devices are not configured to measure high-current levels. As a consequence, engineers use CTs to step down the current levels to measure it. Once measured, they use the current transformer ratio, or CT ratio, to calculate the actual current from the measured current.

The importance of current transformers (CT) in today’s solar installs

JavaScript seems to be disabled in your browser. You must have JavaScript enabled in your browser to utilize the functionality of this website. Current Transformers are a vital piece in metering and current monitoring applications. Current transformers are commonly used in metering and protective relays in the electrical power industry. And it is very important that the current transformers be installed correctly for the entire process to work properly.

Every current transformer has polarity markings on it even power transformers. These are commonly called H1 and X1. A current transformer is wound so that when primary current enters H1, then secondary current leaves X1. Therefore, current transformers should be installed with the H1 side pointing towards the power source. The orientation of current transformers in a circuit are dependent on what they will be doing. If the current transformer is feeding single ammeters, then orientation is not important.

However, if the currents must be algebraically combined, like in a KWH Kilowatt Hour Meter or a ground fault relay, then it is important to to know what direction any one current is flowing versus the other ones. For example, in a ground fault relay, balanced currents must sum to zero. When measuring kilowatts KW you must make sure that all of your current transformers are pointed in the same direction and that they correspond to the orientation of the voltage transformers as well as that they are on the correct conductors.

Ideally, the voltage transformers would be connected with their H1 lead on the first line. The current transformers should have their H1 side pointing toward the source of the current. Current Transformers installed on the three phases on the load side of a power panel. Photo courtesy of the U. Coast Guard. Current transformers are generally located in the main breaker panel or in branch distribution panels where space is always at a premium.

Current transformers with mounting feet are also available if appearance is important or if there is enough room in the panel to accommodate this type of mounting. If a CT test switch is used, the switch must have a “make-before-break” contact pattern to assure that the current transformers are not open-circuited during transition. The power should be disconnected during installation. However, often times this is not possible due to critical loads that cannot be shut down. Split-core current transformers are a great solution for this!

Under NO circumstances may the secondary circuit of a current transformer be opened when current is flowing in the primary circuit. The voltage generated in the primary winding is stepped up by the turns-ratio of the current transformer typically by a factor of several hundred. The voltage in the primary winding can reach several thousand volts in a fraction of a second if the secondaries are made open-circuit while current is flowing in the circuit being metered.

Such high voltages can be dangerous to personnel and can cause serious damage to the transformer or equipment connected to it. Such damage may not be immediately obvious, but will certainly lead to incorrect operation of the equipment. In LV low-voltage installations, it is recommended that the current transformer secondary leads S2 be grounded as protection against static voltages or insulation failure. Only one connection to ground is necessary and it is general practice to make this at the transformer.

In HV high-voltage installations, the current transformers must be grounded. Current transformers used as part of metering equipment for three-phase Amp electricity supply. Photo licensed by Ali gwc. Powered by Turtlehut Internet Marketing. Ram Meter Categories. Category Navigation: Installing Current Transformers Jun 3, Posted in Technical Information. Recent Posts Check out our August Newsletter! Ram Meter Inc.


Current transformers reduce high voltage currents to a much lower value and . happens when we connect together three individual transformers in a star or. CT Installation Guide. Figure 1: Typical CTs being used: Shown above are two typical current sensors – one for DC and one for AC. Current sensors primarily.

JavaScript seems to be disabled in your browser. You must have JavaScript enabled in your browser to utilize the functionality of this website. Current Transformers are a vital piece in metering and current monitoring applications.

Current transformer hook up The basics of current transformers Text itself creates just then solid to the norcross. Organization okcupid tutorial makers.

By using our site, you acknowledge that you have read and understand our Cookie Policy , Privacy Policy , and our Terms of Service. I Need to design and make a CT current transformer to energize a 3ph relay with sufficient voltage and current from low load to full load.

Safety Tip: Current Transformer

Discussion in ‘ The Projects Forum ‘ started by diebog , Mar 22, Load More Articles. All About Circuits. Reply to Thread. Mar 22, 1. Mar 23, 1.

Transducer Wiring 101

This video was brought to you by GeneralPAC. Consider subscribing and supporting through patreon. This is a mechanism for you to support us financially so we can continue making high quality power system video tutorials. Our corporate sponsor for this topic is AllumiaX. Contact them for industrial and commercial power system studies. Current Transformers transforms current at higher magnitude of current and high magnitude of voltage to current that is at a lower magnitude and much safer magnitude of voltage. So let’s setup a scenario. So let’s assume that we have a power system like a generator for example that’s generating voltage at It’s hooked up to a step up transformer that steps the voltage from And that distribution transformer transforms that voltage from kV to

The primary of a current transformer typically has only one turn.

Current transformers CTs are typically install in electrical equipment with lethal high voltage levels. WattNode meters are designed to work only with CTs that have a 0.

CT Installation and Wiring

For installers who are growing their business by offering their customers the Enphase Home Energy Solution, the Enphase Consumption Monitoring CT current transformer is the equipment that performs this important function. Good news, very often you can. A little time spent building your best practices ahead of time will spare you and your crew from missed opportunities, and save you costly troubleshooting time later. Keep reading to learn how to build the most efficient consumption monitoring CT installation process. In a residential setting, CTs are small devices used throughout the electrical system, on distribution lines and at the circuit level, to efficiently measure electrical current. Current measurements are used to calculate power and energy, and used by the Envoy to control microinverter and storage system operation. Below are recommendations that will simplify and streamline the CT installation process. These tips are broken down into three categories: Continue to the bottom of this post for a detailed description of each step. We recommend that all installers download the app to their Android or IOS devices and log in to Enlighten Manager before going to the job site. At some sites, the conductors or the bussing between the utility meter and the main breaker of the service panel are not accessible or do not have adequate space to fit the consumption CTs.

Current transformer hook up

Issue Current transformers should be oriented in a particular direction, with one side pointing toward the source of electricity upstream or high side , and the other pointing toward the load downstream or low side Product Line Current Transformers Environment Metering and Power Monitoring Cause Current Transformers CT’s may easily installed backwards on their respective load conductors. It saves time and money to ensure that they are installed with the correct orientation before energizing the load. Installation and maintenance of this device should only be performed by qualified, competent personnel that have appropriate training and experience with high voltage and current devices. CT’s installed backwards provide inverted signals to the meters to which they are connected. Most meters note the polarity of the signal received from the current transformers, and use that polarity to help determine the direction of the flow of electricity, assigning a positive or negative value to calculated power and energy.

3 Phase Current Transformer Wiring Diagram

We find that a lot of installers and end users get confused by selecting and installing current transformers CTs. I hope to dispel some of the mystery behind CTs. The CT is instrumental in measuring electricity. Any meter that gets installed will require you to connect directly to voltage and current. CTs come in all shapes and sizes. The size is usually directly proportional to the amount of current you need to measure.


When alternating current travels through an electrical conductor, like cable or bus, it develops a magnetic field at right angles to the flow of current. The principal function of a current transformer is to produce a manageable level of voltage and current , proportional to the current flowing through its primary winding, for the operation of measuring or protective devices. In its most basic form , a CT consists of a laminated steel core, a secondary winding around the core, and insulating material surrounding the windings. If this current is passed through the primary winding of a CT, the iron core inside becomes magnetized which then induces a voltage in the secondary coils. If the secondary circuit is closed, a current proportional to the CT ratio will flow through the secondary. Window and Bar Type CTs are the most common current transformers found in the field. Photo Credit: The primary winding can consist merely of the primary current conductor passing once through an aperture in the current transformer core window- or bar-type , or it may consist of two or more turns wound on the core together with the secondary winding wound type.


JavaScript seems to be disabled in your browser. You must have JavaScript enabled in your browser to utilize the functionality of this website. Some of the most common questions concerning connection diagrams from the transducer specification sheet or from the label attached to the unit involve OSI AC current, voltage and power transducers. Never install OSI transducers using live voltage or current. Never connect or disconnect a current or potential transformer on a transducer with primary current or voltage present. The diagrams discussed here also reflect a transducers DC output analog signal.

Skip to main content. Current Transformer. In Stock. I am using to monitor a well pump Tietz Gainesville, Florida. This thing is cool! I am using to monitor a well pump current draw.

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