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.

If you are looking to remodel, expand or sell your home, there's a good chance you will have a close encounter with your local building code. These laws can be extensive, confusing and change frequently. The code is there for your safety, but it can still be frustrating to deal with. Older homes in particular are likely to have outdated technology that wouldn't pass a current inspection. Before embarking on a project, take time to understand what the laws are and how they can affect you.

What Is Building Code?

Just about anything you want to do to your home beyond cosmetic changes probably has a corresponding law. Building code covers a number of standards mostly related to safety, including but not limited to HVAC, the electric system, plumbing, the structural integrity of the building and fire safety. If you own a rental unit, there are probably additional standards that you are required to meet before accepting tenants.

Of course, specific housing codes vary by municipality, although most are based on models like the International Residential Code and the National Electric Code. Go to your city or town  website or visit the building department for more information. You can also look up many city and municipality codes from around the country on a website called Municode.

Is My Old Electric Wiring Safe?

The electric code is one of the most important pieces of building code, because failing to comply can endanger your home and property. Some common violations include improperly sized connections, overfilling outlet boxes, not properly grounding and not spacing outlets correctly.

Many code problems require only a simply fix, but others can be a much bigger undertaking. For example, old houses may conduct electricity on knob and tube wiring, which became obsolete in the 1940s. This type of wiring can put your home at risk and isn't equipped to handle high power loads typical in modern homes. If you still have knob and tube, you may discover an expensive upgrade is necessary when it's time to sell the house.

The laws governing electric systems are complex and confusing to many homeowners. The national code on which most cities base their own laws is 1,000 pages long -- far more than the average home DIY-er is able to digest. You could inadvertently run afoul of the law by doing something as simple as replacing a light fixture without upgrading the wiring to the most recent standards. It’s wise to consult a qualified electrician before undertaking a project  so you don’t find yourself in over your head – and on the wrong side of the law.

What if I'm Out of Compliance? 

If you have an older home that doesn't meet the current laws, don't panic. Usually older buildings are grandfathered in when the codes are updated. However, if you want to modify or replace parts of the house, you might be required to do additional work to bring any outdated aspects into compliance.

Do your research so you understand when you need to pull a permit or bring in a city inspector. Talk to local officials up front so they can help you understand how to proceed. When in doubt, hire a qualified professional experienced in local housing laws to let you know where you are up to code and in what areas you fall short.

Your local Mister Sparky® electricians are always here to help. We can advise you on bringing your home into compliance with local laws and do the work for you. Give us a call for more information.

Summer storms and problems with the electrical grid can lead to power outages wherever you may live. There was a time when candles and flashlights were really the only way in which to make it through a power outage in one’s home. Thankfully, those days are far behind us at this point. If you are interested in keeping your home powered, despite the fact that you’re receiving no power from the grid, we strongly recommend that you consider the installation of a whole-house generator. More specifically, we suggest that you give the use of an automatic standby generator in  Needham Heights, MA some serious consideration. 

Some homeowners may only be interested in keeping an appliance or two running in the event of a power outage. In such instances, a portable generator may suffice, though these systems are really better suited for the campground or use at tailgating events. For whole-house protection, though, a whole-house generator is obviously the way to go.

What happens when you’re not at home to activate your generator, though? Do you just leave a chest freezer or your refrigerator without any electricity to keep them up and running, even if you’re going to be gone a few days? With the use of an automatic standby generator, you won’t have to worry about integral systems shutting down in the event of a power outage, even if you are not there to start up the generator manually.

A whole-house generator is wired into your electrical system directly, and automatic standby models are designed to detect the loss of electricity to the system. Once it has, the generator springs into action, powering your systems so that you won’t have to worry about spoiled food, failed security systems, and so on.

Everyone wants to save money.  With the economy, still slow and unemployment high, family and business budgets are tight.  Thus, we’re all looking for ways to lower our bills, and there aren’t many bills more devastating to budgets than the electric bill.  Not to mention those bills during a brutal Texas summer.

At the same time, people are finally beginning to understand that the damage we do to our environment is harmful in the long run, and are trying to find a way to reduce our impact on the planet.  A lot of the time it seems like we must choose between saving money and helping the earth.  That is simply not the case when we’re talking about options for lighting your home or business.  The employees of my Plano electrical service tell you that you can actually do both at the same time, and that it‘s as simple as changing a light bulb!

Light bulb shopping has changed a lot in the last ten years.  Our choices are no longer limited to the incandescent (and sometimes halogen) bulbs we all grew up with.  Today fluorescent CFL lights are available in almost every store, and LED lights are starting to become more widely available as well. These bulbs use far less energy to create the same amount of light, which ultimately means less energy you have to pay for.  The savings can be seen with a single bulb.

For example, if you replace just one 60-watt incandescent bulb you use four hours each day with a 12-watt LED equivalent, you’ll wind up saving almost $10 a year on average! These bulbs can save you money and hassle in ways you might not think of at first.  For instance, LED and CFL bulbs produce very little heat when compared to an incandescent bulb which means that they don’t attract insects, and that your air conditioner doesn’t have another heat source in your house to cool down.

There are electrical benefits to having cooler bulbs too: less heat being generated by light bulbs means that there’s less heat stress being placed on the sockets and fixtures they’re attached to.  Less stress on the fixtures means that they have a much longer life, and that you’re saving money you’d otherwise have to spend on repairing or replacing them.

All these choices beg the question of which type of bulb is better.  From an electrician’s view, they’re both superior to the old kind of bulbs.  Personally, I think LED lights are superior to fluorescent CFL lights right now.  The technology that makes CFL bulbs work is still primitive.  Think of what cell phones looked like in the 1980‘s compared to today; right now, the CFL bulbs you can buy are the fluorescent bulb version of those old brick phones. LED lights have very distinct advantages:

These reasons are why I generally recommend LED bulbs; they’re more earth-friendly, easy to dispose of, use less energy than even CFL bulbs, and last a very long time.  They can be more expensive than other bulbs, but you’ll save enough money on your power bills in the long run to come out well ahead!