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1 Phase vs. 3 Phase Motors

By January 17, 2014February 16th, 2020No Comments

Most residential misting systems are designed for 1 Phase power because that is typically the only available power supply. However, some commercial and most industrial applications do have the option of using 1 Phase or 3 Phase power. So the question becomes, which is a better option.

In terms of the actual performance of the mist system (its cooling or humidification capability), there is no difference between one that uses 1 Phase and one that uses 3 Phase. The real issue becomes the longevity of the motor and the efficiency of the misting systems operation.

Generally speaking, 3 Phase motors will run cooler; they have a higher Efficiency rating (they are more efficient to operate); they have a lower amp draw (FLA); they have a higher Service Factor (SF); they are more reliable for continuous duty applications; and they are more forgiving when it comes to mist systems that are designed to cycle on and off on a regular basis (3 Phase motors are suitable for up to 20 starts per hour while 1 Phase motors are only suitable for less than 10 starts per hour).

Specifically, here is a direct comparison for two generic motors. Both are 2 HP, 4 pole motors (running at 1750 RPM) operating at 230V 60Hz.

Phase                                           1                                     3
FLA                                             10.2                                 6.2
Efficiency                                   75.5                                 80
Power Factor                             65                                    78
Insulation                                 B                                        F
Service Factor                         1.15                                  1.25
Cost Basis                                $733                                $517

In this example, the 3 Phase motor has approximately 40% lower amp draw; has an improved power factor; has a higher insulation rating allowing it to safely operate at a higher temperature (B insulation rated at 266 degrees Fahrenheit while F insulation is rated for up to 311 degrees Fahrenheit); has a higher Service Factor (Service Factor relates to the capability of the motor to operate at horsepower requirement above that stated on the motor nameplate), and has a lower cost basis.

Although this information is based on two specific motors, the results will be similar when comparing most 1 Phase to a 3 phase motor option.

Based on these differences, the net result is if 3 Phase power is available, 9 times out of 10, a 3 phase motor is the preferred option.

Conditions may vary so it is recommended that you contact Fogco Customer Service at 480 507 6478 to discuss your site conditions and your specific mist system requirements.