Wire Current and Resistance

Like garden hoses, electrical wires are only designed to carry a limited amount of current to prevent short circuits. Unlike water and garden hoses, however, the current capacity of a wire is not directly proportional to the gauge.

A six-gauge wire (American Wire Gauge standards), for instance, has a 4.11mm diameter and a current capacity of 37 amps for power transmission, while a twelve-gauge wire only has a 2.05mm diameter and 9.3 amps—more than half the capacity. This isn't just because the wire is smaller; the electrical resistance grows as it shrinks.

How to Transform AC into DC

It’s not difficult to distinguish alternating current from direct current. By observing how some electricity-powered appliances in your home function, you can tell which ones use AC or DC by their distance from the power source. Those plugged farther away from the power source use AC, while those connected directly to the source use DC.

Indoor vs. Outdoor Protective Current Transformers

As the name implies, protection current transformers are used to protect electrical systems from damage. They reduce the high current flowing in a power system element to lower, manageable values ideal for relay operation. Protective CTs from power monitoring equipment providers can also isolate the relay circuit from the primary, while allowing for the use of standardized current rating for relays, which can either be 5 or 1 ampere.

Split Core vs. Solid Core Current Transformers

Ensuring the safety of measuring large currents in industrial settings presents many challenges. For one, measuring a large voltage via small burden resistors in a circuit is not only ineffective, but also potentially hazardous. Common current measuring instruments can typically measure a few amperes, but you can’t use them for long. Prolonged use may lead to damaged equipment, or worse, physical injury.

The Two Main Types of Current Transformers

Current transformers (CT) are generally used to measure and control current in an electrical system. High current levels cannot be fed to a system’s relays and meters, and it’s a CT’s job to quantify our manipulate current to a level that these devices can handle. Based on function, CTs can be classified as follows:

Measuring CTs

This type of CT is typically used in combination with measuring devices for the accurate measurement of energy, current, and power.

Meet the Cores

At the heart of a current transformer is a slab of magnetic material known as a magnetic core. to put it simply, the measurement mechanism wouldn't work without a magnetic core.

Enveloped by two upper layers of insulation and secondary windings, the magnetic core emits the magnetic field necessary to generate electromagnetic energy. Through the Hall Effect, the current transformer enables a hooked measuring device like an ammeter or voltmeter to get accurate readings. Solid and split-core transformers are known to employ magnetic cores.

Thinking Accuracy with Current Transformers

Accuracy is, and probably will always be, a contested subject. Even the readings on the most sensitive gauges ever made will be subject to factors beyond anyone's control. This is why it's reasonable to consider a margin of error every time you take a measurement, especially when it comes to currents.

Given that current transformers are always on the lookout for unusual energy spikes, accuracy must be their most defining feature. They don't have to be perfectly accurate, just accurate enough to confirm the readings and help managers make sound decisions. However, no one-size-fits-all transformer exists at present.

Analog vs. Digital Sensors

There are many different types of sensors and transducers, but in general, all of them can be classified into two basic types: analog and digital. So which one is more useful to your needs? Find out below.

Analog sensors

Analog sensors create continuous and generally proportional output signal to that of the quantity being measured. Physical quantities such as Strain, Temperature, Pressure, Displacement and Strain, among others, are all analog because of their continuous characteristic. Analog sensors share this continuous nature, producing signals that change smoothly over time.

Real-Time Data from a Current Transformer

Current transformers can be hooked up to an ammeter, although the resulting amperage reading only paints a partial picture of an office or factory's energy consumption. A gauge system brings out the transformer’s full potential by providing real-time data that includes amperage, voltage, frequency, power factor, and more. Access the data on the computer, and you'll get a bird's-eye-view of your power consumption patterns.

A gauge system is a mother unit that can support a number of conductors. It gathers data from all connected units and, depending on the model, may upload the data on the Internet through an Ethernet connection. This enables the user to access the information, whether onsite or offsite, and make quick decisions.

Split-Core Transformers: Common Features

Modern split-core transformers are easily installed, easily connectable devices that can be attached to virtually all types of wiring terminals. Preferably, a split-core transformer is attached to electrical wiring by snapping the device around the conductor. High quality split-core transformers—such as those produced by Magnelab—have the highest standards in terms of interleaving joints and self-locking mechanism. Typically, these products have a rated accuracy of +- 1 percent between 10 and 130 percent of their graded input.

An Energy-Efficient Future with Split-Core CTs

Split-core current transformers (CTs), among other things, are used to conduct electrical load surveys. Offices and factories periodically ask for a thorough assessment of their energy consumption and ways to get more for less. Such an assessment answers the question: "How much energy does it take the load to convert electricity to light, heat, or motion?"

A War of Currents

When Nikola Tesla created alternating current (AC) in the late 1800s, the world didn't realize that electricity was about to change for the better. In fact, businessmen like Thomas Edison, a fellow inventor, tried to discredit Tesla for the discovery since he invested heavily in direct current (DC). In fact, many of Tesla's inventions conflicted with business interests.

What exactly was in AC that gave DC a run for its money? AC traveled in a wave-like motion, moving power more efficiently than DC’s straight-line motion. This innovation meant electricity can be distributed to long distances using low voltages, which is much safer. Tesla demonstrated the safety of AC by using his own body as a conduit to light up lamps.

Why Is Current Transformer Important?

Electrocution is one of the leading causes of death among construction workers, killing an average of 143 personnel each year. Whether it’s overhead or underground wires you are working with, or are near your working area, you are at risk of electrocution. Unfortunately, like humans and animals, high voltage electricity is also dangerous to devices, for instance, a television breaking down after receiving more voltage than normal.

One particular device that can easily break down when applied with high voltage electricity is the ammeter, an instrument used to measure electric current. This device allows you to know your regular energy consumption. The problem with ammeter is that despite its function as a current measuring device, its electronics are too sensitive and can burn quickly when subjected to high voltage electricity.

Typical Applications for DC Current Sensors

The ability to monitor currents discretely is often a requirement for the accurate control of the complex DC circuits used in many commercial and industrial applications today. DC current sensors are often used to facilitate the monitoring required. These are used in applications such as:

Safe, Accurate High-voltage Measurements

Regardless of current type, all high-voltage currents pose a significant risk to the life and limbs of the people who work with them. Given this, one might be tempted to think that avoiding high-voltage currents altogether might be best for all involved. However, there are instances when working with high-voltage currents cannot be avoided.

Take for example power transmission. In this application, electricity is raised to a higher voltage to reduce line loss at long distances. Additionally, many industrial devices require higher voltages due to their higher power requirements.

Choosing a Core Transformer: Factors to Consider

Most industrial processes that rely on electricity require the use of power meters. These devices allow operators to measure just how much electric current is being utilized and thereby monitor changes or fluctuations that may affect productivity. Power meters and other electrical measuring instruments come with a small but extremely vital current transformer (CT), which reduces the level of electric current that passes through the measuring instrument.

The Current Transformer’s Role in a Circuit

Electrical measurements are critical to industries that rely on electricity for production continuity. After all, aside from potential interruptions due to sudden current flow changes, over fusing can lead to fires and increased current flow through the wires. Constant monitoring of the current flow using measuring instruments, such as an ammeter, is imperative in any electrical system.

Unfortunately, most measuring instruments cannot take the current flowing through live wires. Like how electricity can severely injure living things that come into contact with an open electrical source, so does the circuitry inside these instruments burn when subjected to excessive currents. An electrical measuring instrument has to be protected so it can continue to measure alternating current without the risk of over fusing.

Arming Your Clients against Electric Shock

When you’re in the business of providing power monitoring equipment, you should always be ready to offer safety precautions to your customers. With the potentially fatal hazards associated with electrical systems, your customers should be fully aware of the risks and invest on ways to prevent them. By giving them useful information, you may even bring them to better appreciate the technologies you provide.

Notes when Using a DC Transformer

Nearly all households in the U.S. are using AC (alternating current) power, mainly because it is easier to change the voltage of this type of electricity than DC (direct current) power. However, some household appliances, like a TV, require DC power to run properly, making a DC current transformer at home important.

Energy Tracking: Why It’s Done and What You Need

As a retailer of power monitoring equipment, your customers are going to request for various devices for different purposes. You have to be familiar with the principles and the tools needed for these purposes, so you can assist your clients well. Here are some common reasons why energy tracking is done and what devices may be needed: