Electric motors power everything from tiny electronics to massive industrial pumps. Yet, they all work on the same basic principles. Though AC motors seem ordinary, there are complex activities going on behind the scenes.

The simplest types of motors are three-phase AC motors. They convert a rotating magnetic field into mechanical rotation. The basic parts of an AC motor are the stator, rotor, bearings, drive shaft, and frame. The supply power is connected to coils of wire that are wrapped around laminated iron cores in the stator; the stationary part of the motor. When the coils of wire receive current, they generate a magnetic field known as poles. Each phase of power has the same number of poles; the poles are spaced evenly around the stator.

Historically, speed control of three-phase induction motors was very difficult. The only way to change the operational speed is to change the frequency of electricity supplied. Today, this task is accomplished by use of a variable frequency drive or VFD. This device is made of three main components: a rectifier, a DC-Link, and an inverter. The rectifier takes the incoming AC voltage and converts it to DC voltage that can be used by the electronics in the VFD. The DC-Link then uses capacitors to help smooth out the DC voltage from the rectifier and feeds it to the inverter.

The inverter then converts the DC voltage back to AC voltage. The inverter also controls the output frequency of the AC power by sending precisely timed pulses of DC power at specific voltages to rebuild the AC sine wave.

With a VFD, not only can the output frequency be controlled, but it can be slowly ramped up. This allows for smoother starting and can be adjusted to keep a motor spinning at a specific frequency. VFDs can produce three-phase power from a single-phase source, or even a DC source, to power highly efficient three-phase motors in locations without a three-phase supply. VFDs can also be incorporated into a PLC system to allow for automatic or remote control.

The combination of a VFD and AC motors offers a wide variety of functions and increased efficiency. Basic understanding of these technologies is essential for any electrician.

Now encroaching into Post-Graduate territory, the 20+ year-old student has a more refined set of needs. Cool isn’t a requirement as much as function. The grad student is faced with the problem of desperately wanting to be a sophisticated adult, but is hindered by full schedules and mounting education costs. Be a hero by giving your favorite 20-something student a gift that acknowledges this new phase of their life:

It used to be that energy-efficient green housing was once not only rare, but extremely expensive, as appliances and non-conventional layouts that are characteristic of such properties could only be acquired at a premium. However, that trend has changed, and now environmentally friendly and energy-efficient are descriptors at the top of many home buyers' checklists when shopping for a new residence.

According to a study conducted by industry research firm McGraw Hill Construction, green housing accounts for roughly 20 percent of all new residential buildings across the country. Even during the Great Recession, the industry for energy-efficient housing was worth roughly $25 billion in the United States, and analysts indicate that this figure will only grow as green goes mainstream.

"The green building market has evolved beyond the crunchy-granola, Boulder types," David Johnston, a Colorado consultant and co-author of "Toward a Zero Energy Home," told the Wall Street Journal in a story on this more-popular-than-ever kind of residence. "We have mainstream builders doing this."

The source reported that here in the Mid Atlantic, residents are helping to lead the way in lowering utility bills and lessening their dependence on the energy grid. One home profiled in the story looked at a net-zero house in Frederick, Maryland, that costs the residents nothing on electric and water bills at the end of the year thanks to upgrades to their traditional brick house.

Make sure that the voltage of your LED light is compatible with the truck’s operating voltage. For example, you wouldn’t want to use a 6-volt light with a 12-volt system. That bulb will burn out very quickly. Or say you use a 24-volt light on a 12-volt truck—if you get any light output at all, it wouldn’t be near what is possible from that light.

When you’re installing new LED truck lighting, lubricate sockets, terminals, or any associated electrical connections with dialectic grease to seal out moisture and prevent corrosion. Because the grease can dry up, you should check connections periodically. It’s important to keep connections lubricated to maintain the functionality of your light. However, too much grease can interfere with the terminal/socket connection and prevent a light from functioning.

Be sure to know and understand the rules set in place in the light’s warranty. Doing unauthorized repairs or disassembling the light will most likely void its warranty. A driver should also know the correct person to contact about their LED truck lighting in case of light malfunctioning. The point of contact could be the fleet’s parts department, the purchaser, or the company from which the light was purchased.

For technical questions, don’t hesitate to call us toll free at 866-590-3533. Our customer service and technical support teams are available from 8:30 a.m. to 8 p.m. CDT Monday-Thursday and 8:30 a.m. to 4 p.m. CDT on Friday.