Variable Speed Control For Filtration

In 1985 when Pure Air Systems was formed, the air filtration industry was using standard induction ( copper wound ) AC motors to run the fans that moved the air across the various types of filter media. Most often these fan powered units used HEPA filters as their primary filtration media.  Since HEPA filters have a fair amount of resistance due to their very dense media design,  motors in the range of 1/3 HP to 3/4 HP and larger were used for these applications. For the most part, these motors were all single speed, 120 volt, 60Hz  AC motors. Using any type of speed reduction controller with induction motors was difficult as the reduction in voltage to reduce speed also increased the heat load on the motor and created a hum or whine sound when dialing down the speed. As a result, most of the systems ran at one speed and one voltage.

In the late 90’s General Electric introduced a variable speed motor referred to as an “electrically commutated motor,” or ECM for short. This motor operates on using magnets rather than copper winding’s and can run forward or backward at any speed from 1% to 100% in 1% increments when controlled with a digital controller. Further more, it was designed to operate at 120/240 volt, 50/60Hz so it could be  used anywhere in the world. This new motor technology provided for variable speed control for filtration systems.

When using the standard induction motors the fan ran at one speed, which was high. This made a fair amount of noise and made it difficult to use it in areas that were occupied or where individuals were sleeping, reading or watching TV. The addition of the ECM motors allowed for use of even larger HEPA based air filtration systems to be used anywhere as the speed of the blower can be reduced so that the sound levels from the fan noise are low enough not to disturb people where the system is being used. Even at low speeds, the filtration efficiency’s are very good so moving air slowly over a long period of time is as effective as moving it at high speeds for short periods of time.

Pure Air Systems has over 6 models of HEPA systems designed to provide filtered air in any environment with a high degree of control. These units can be attached to existing ducted  HVAC systems or as stand-alone units. For more information on the complete line of  HEPA and Carbon based air filtration systems please go to our website at: or contact us on our toll-free number: 800-869-8025.

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Cutting Electrical Costs Using ECM Motors

Everyone who owns a home knows that the costs of home ownership go well beyond just paying the mortgage, insurance and taxes. It also includes the cost of heating and cooling the home; which can be significant.

One of the major uses of electricity is the electrical motor that turns the fan in the forced air heating/cooling system found in most homes. The motors range in horsepower from 1/3 to 3/4 HP and many of them are the standard induction motors. These motors use a lot of electricity and are relatively inefficient; often running 12 to 24 hours per day especially in the hottest and coldest months of the year.

Depending upon the electrical costs in your area; usually measured in costs per kilowatt hour, your overall electrical costs to run your home may range from as low as $50.00 per month to upwards of $300.00 per month or more for larger homes. Interestingly almost 40% to 50% of these costs may come from running the heating/cooling fan motors.

Since the early 2000’s the ECM motors or Electrically Commutated Motors were introduced ( BY GE). Unlike standard induction motors that use windings and have only two to three speeds available, the ECM motors use a series of magnets to turn the motor shaft and have a speed range that runs from less than 10% to 100% of available power ….and this can be digitally controlled in 1% increments so you have a very wide range of speeds to run the motor.

Not  only does this variable speed capability allow for better air flow control for your heating/cooling fan but is also uses up to 50% less electricity than the standard induction motors running at the same horsepower.

Pure Air Systems was the first HEPA based air filtration company to introduce these motors as the main motor drive unit for the complete line of fan powered, commercial grade, certified HEPA systems.  In fact, PAS introduced the GE ECM motor drive systems in 1999, almost 3 years before these motors were introduced into the HVAC systems. Today, the ECM motors are ubiquitous in the heating/cooling and appliance industries.

Aside from their variable speed and low power consumption capabilities, they are also capable of being programed for a variety of applications. For the HEPA units these motors are capable of automatically ramping up when the pressure drop across the HEPA filter starts to increase and thus maintaining the same air volume throughout the life of the HEPA filters.

When the HEPA units are used in conjunction with a heating/cooling system also using the ECM motors, you have the best of both worlds.

For more information on the Pure Air Systems ECM driven HEPA systems please go to our website at: www.pureairsystems. com

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