ABOUT THE BRAND ELECTRONICS POWER METER 

The BRAND ELECTRONICS DIGITAL POWER METER uses a combination of innovative software and hardware design and common off the shelf components to produce a simple to use, high quality, accurate, durable and affordable power measuring instrument. 

The primary displays of the POWER METER are power and power used. Several  special features have been built into the POWER METER to increase its utility. The total cost to run the load can easily be displayed by entering the cost per kilo-Watt hour (which can be found on your electric bill, or by calling your utility.) You can also calculate the cost to run the load for one month (the most common billing period for electric bills.) 
 

SAFE, DURABLE, ACCURATE-The POWER METER was designed to be safe to use. The circuitry utilizes listed components for all high voltage componentsand physical design  completely separates high voltage from the user.  The internal circuitry is protected against voltage spike, surges, etc, and the self calibrating circuitry compensates for temperature and other factors. The instrument is designed to sustain rough handling, such as tossing the instrument in a tool box, or dropping it. The POWER METER has been tested  with a laboratory grade Yokogawa Power Meter (Model 2533) to ensure accurate power measurements regardless of load or power supply.  

WHY DO I NEED THE DIGITAL POWER METER? WHAT CAN'T I USE MY AMMETER? 

A common misconception is that power is simply the product of voltage times current, implying that any ammeter can be used to determine power usage. This is only true in  a few special cases. Voltage and current work together to produce  power.The DIGITAL POWER METER utilizes a combination of analog and digital signal processing to calculate power. It  is designed to measure power in AC (alternating current) systems. (DC applications are also available, please call) 

POWER FACTOR

In AC systems, voltage and current go from positive to zero to negative generally 60 times a second (60 cycles or 60 Hz). If voltage and current are "high" or "low" at the same time, then they are said to be "in phase." A common term to describe the time relationship between voltage and current is called "power factor." When voltage and current are "in phase," the power factor is generally 1 (surprising, this is not always the case ). When the current peak follows the voltage peak, this is called " lagging power factor," when current leads voltage, this is called "leading power factor." When voltage and current are exactly opposite ( when voltage is at a peak and current is zero,or vice versa), the power factor is 0. 

"REAL" POWER

Utilities charge us for "real power" i.e. how much work must actually be done by a generator (no matter how it is driven, by a steam turbine, internal combustion engine, dam, wind, etc). To find "real power," you multiply volts time amps times power factor. The power factor is determined by the load, that is, the device using the power. A light bulb produces light by simply heating up a thin metal filament and is called a resistive load (other examples are heaters, toasters, etc). Resistive loads have a power factor of 1, and are the only loads where you can find real power by simply multiplying voltage times current. 

A common induction motor, such as those found in washers, freezers, refrigerators and air conditioners,  work by storing some of the electricity it uses in a magnetic field. This storage causes the voltage and current to be high at different times, and the resulting real power usage can be a small fraction of voltage times current; this fraction increases as the motor is loaded. For example, an air compressor at start up with an empty tank may consume only 1000 watts, but would over 2000 watts when near shut off pressure. If you measured the current going to the compressor motor as it is loading, it only goes up a little bit, not by a factor of 2! The reason is that the power factor of the motor is changing as the motor is loaded. 

Measuring power can be very complex, however, measuring real power used by light bulbs and induction motors can be very simple compared to many modern loads. Computers, energy efficient lights and energy efficient freezers,  have circuitry which draws power in complex ways. 

The BRAND ELECTRONICS DIGITAL POWER METER accurately measures the power used by these complex devices. It does this by measuring  current and voltage approximately 4000 times per second. These values are  processed and the power used is updated 3 times every second. The POWER METER accurately compensates for changes in frequency (a gas generator might be running at 40 Hz or 80 Hz), voltage (85-150 volts) and supply "wave form." Power supplied by  utilities comes as a nice "sine wave," that is  the voltage and current change with a very smooth curve. Many generators and inverters supply power with jagged or square transitions. This makes power measurement even more difficult. All of this is made irrelevant by the way the DIGITAL POWER METER calculates power. 

WHY WOULD I WANT TO SPEND $150 TO MEASURE POWER? 

SAVE MONEY

Most people spend at least $500 EVERY year on their electric bills. Where does it go? How much does your freezer, computer, air conditioner, TV really cost to run? You can use the POWER METER to accurately find how much it costs to run these devices. Armed with this information you can more easily find ways to cut down costs. Turn the thermostat down a little on the freezer, turn the computer off at night, etc. You could easily save enough money to pay for the POWER METER in a year or less. 

SAVE NATURAL RESOURCES

Producing electricity consumes resources, dams rivers, uses open space. No matter how the electricity is produced, some resource is consumed, oil, coal, water resources, prime space, wood, etc. Using your POWER METER you can accurately find where you can use electricity and make informed decisions about your usage. Maybe that basement dehumidifier isn't worth running, or that extra refridgerator isn't worth the cost. With the POWER METER you are able to make more responsible decisions about how you use your electricity.

SAVE TIME

Professionals who make their living working with electricity, whether an electrician, a repair technician, a consultant or an engineer often spend valuable time on problems related to electrical power consumption. Up to this time, purchasing an instrument that accurately measures power was a major investment. With the POWER METER the electrician can more easily diagnose the circuit that keeps tripping, or more precisely size a circuit line. The repair technician can use the POWER METER to determine if a device is drawing too much or too little power to help diagnose a problem. An engineer could use the POWER METER to measure system efficiency. The consultant can use the POWER METER to help clients with energy management decisions. 
 
BEST BRAND FOR THE MONEY

Brand Electronics was able to develop an affordable POWER METER for several reasons. The two principal partners have extensive experience in real-time software development and innovative design. In addition, recent developments in "computer in a chip" technology have brought the necessary high-speed complex capabilities needed for real time power measurement at an affordable price. The combination of these two factors has made the POWER METER possible. The BRAND ELECTRONICS DIGITAL POWER METER finally brings affordable power measurement to the market.

PRINCIPALS

Ethan holds a Masters Degree in Engineering, and has been a licensed and practicing engineer for over 20 years. Ethan holds a Patent on an early version of the DIGITAL POWER METER (US Patent 5,869,960).
The POWER METER uses a single chip microcomputer, programmed by  Richard McGrath. Rick holds a degree in Engineering, and his backround includes over 15 years in software development and maintenance for a real-time training simulator.