Aim Dynamics: February 2015

Wednesday, February 18, 2015

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.

Monday, February 16, 2015

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.

Sunday, February 1, 2015

Innovative DC Current Sensor System Promotes Responsible Energy Use

Global energy demand will continue to increase due to population growth. In a recent Hydrocarbon Engineering report, Emma McAleavey writes that even with energy efficiency measures in place, residential, commercial, and industrial demand for energy will grow between 2010 and 2040. Fortunately, North America and Europe will see the lowest increase in demand. Building code updates, energy efficiency mandates, and investment in alternative sources of energy are able to keep the rate of increase down to 20 percent. McAleavey reports, though, that it could’ve been 50 percent—at par with Asia, a budding mega-economy.