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Dehumidifier Corp. Blog

Overcoming Voltage Fluctuation Obstacles in the Summer

Posted by TWPdehumidifier on Sep 4, 2015 10:13:00 AM

As anyone who pays an electricity bill can tell you, air conditioners can use a tremendous amount of electricity. When that increased usage is applied across a large population, such as the New York, Madison, or Los Angeles metropolitan areas, the power grids serving those areas are put under a tremendous amount of strain.

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With such an elevated and sustained level of power being drawn, the voltage that utilities are capable of producing will drop. This can have serious negative effects, such as brownouts or the need for rolling blackouts like those in California from 2001 to 2003. In a worst-case scenario, there can be widespread power outages such as the Northeast Blackout of 2003.

By law, power companies are obligated to provide specific voltages within a range of plus or minus ten percent of rated voltage.  Normally over voltage, up to ten percent of rated voltage, is not a problem. Under voltage of up to ten percent normally causes little to no problems.  Most of the motors, freon compressors and electrical components used in refrigeration systems can operate under this range of voltage during steady state operating conditions with no consequence.

Ramifications of Voltage Fluctuations on Dehumidifiers

When power grids are strained and supplied voltage is in flux, your dehumidifier is at risk.

Undervolting is when applied voltage — voltage coming into an electrical circuit — is 10% or more below normal for a period of one minute or more. This occurs most often, though not exclusively, during brownouts or being on the extreme end of the line transformer.

One of the most important parts of a dehumidification system is the compressor. The compressor cools dehumidifier coils, which cool the air and collect the condensation that results. Without a compressor, a dehumidification system simply will not function.

Compressors run on electric motors, which require electricity of a certain voltage. Starting an electric motor requires an even higher voltage. During periods of undervolting, the compressor in your dehumidification system is likely to start and function, but it will do so at a considerably lower torque level.

An electric motor running at a torque level lower than it was designed for will lead to overload and, ultimately, overheat. An overheating electric motor will fail, and cause other problems along the way. The lifetime of insulation, for example, decreases rapidly as temperature increases. Without proper installation, the dehumidifier will not function properly and other components can sustain damage.

Another serious problem is the effect on low voltage control transformers. Twenty-four volts is a typical control voltage used in this industry. When low voltage is supplied to the primary side of the transformer, secondary supply voltage drops as well. If this voltage falls enough, the solenoid in the contactor does not draw in and hold the contacts together adequately causing the contactor to chatter. When this happens rapid starting and stopping of the motors can occur.

Solutions to Undervolting Dehumidifiers

The importance of protecting your dehumidifier from overvolting is apparent. While the cause is out of your control, there are things you can do to mediate the risk.

Simply not running your dehumidifier, while certainly effective at eliminating overvolting, is generally not an option — summer is the most humid season, when proper dehumidification is most important. As a long term goal, you could petition your utility company to upgrade the transformer that feeds into your building.

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There are more direct steps that you can take. If not already present, you can install a capacitor to the motor of your compressor. A capacitor stabilizes the flow of power and voltage by temporarily storing energy until the proper voltage is reached, reducing the chances that your compressor motor will start without the requisite minimum power.

Alternatively, you can install a voltage monitor. As its name implies, this device monitors voltage and completely prevents a compressor from starting during overvolting scenarios.

These devices prevent your compressor motor from starting for only a limited time. Your dehumidification system will automatically resume normal functionality as soon as proper voltage is reached, both protecting your equipment and minimizing downtime.

Learn More

Visit our website today to learn more about capacitors, voltage monitors, and other tools that will help mitigate the effects of voltage fluctuations during the summer.

Topics: Summer Humidity