Los Angeles is undertaking a quiet revolution, a switchover to electric cars. This is a revolution that promises bluer skies and greater freedom from foreign oil. At this writing, the Middle East is involved with its own, noisier revolutions, and the stock market is tumbling thanks to perennial shakes over skyrocketing oil prices. Everybody who wants to be independent of foreign oil right now, raise your hands!

Getting back to the other revolution, the quiet one, going on in Los Angeles… car makers and dealers, drivers, and electrical contractors are all involved in a switchover to electric vehicles (EVs). The government is backing it with tax credits and rebates. More on that in later posts.

In December 2010, Nissan started selling an electric car in L.A., the Nissan Leaf. Early this year, G.M. will start selling the electric Chevy Volt. This revolution isn’t confined to L.A. – all along the West Coast and some of the East Coast, deliveries of EVs to new owners are starting. But L.A. is out ahead of a lot of the rest of the country. The Leaf and Volt won’t go on sale, for example, in South Carolina until next December. Pike Research, a transportation analysis firm, has projected that only New York City will beat us out in electric vehicle sales. Pike Research projects 96,000 EVs will be sold in L.A. by 2017. Of course, EV sales could move faster if the price of gas shoots past projected levels.

Both the Nissan Leaf and Chevy Volt will be priced for middle income families. As electrical contractors in Los Angeles, we’ve already started installing chargers, including in home garages, apartment buildings, and commercial venues.

The Leaf is all-electric with an average range of 100 miles before its battery needs to be recharged. The Volt is a hybrid. With a fully charged battery, it can drive about 35 miles and then, it starts burning gas. Drivers can recharge their Leaf or Volt batteries by pulling out their special cord called a “Level 1 Charger” and plugging it into an outlet that carries regular house current.

The advantage of Level 1 charging is that it’s simple and inexpensive to set up. Hire an electrician to install a circuit in your garage or carport. It will need to be a dedicated circuit, meaning that no other appliances, like a washer, for example, will use it. The outlet will need to be the safety version usual in garages and outdoors (a GFI outlet). Also, your electrician will need to check whether your electrical panel should be upgraded in size to handle the increased power demand. Once the outlet is installed, the EV driver pulls out the Level 1 charging cord that comes with the car, starts charging, and lets the car sit … for a long time.

Level 1 charging is… well, slow. A Chevy Volt battery takes 10 hours from empty to full; a Nissan Leaf takes 20 hours. But help is on the way – Level 2 charging. More on that in my next post or click here for our article which talks about Level 2 Charging.

And did I mention that The Electric Connection website offers $25 off your first electrical job? Plus coupons for Whole House Surge Protectors and other services? Check it out.

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.