Air Compressors

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Kay Industries is a true expert in the application of phase converters on air compressors. The Phasemaster® rotary phase converter can be used on all types of compressors: reciprocating, rotary screw, rotary sliding vane and centrifugal, as well as any other machine tools you utilize in your operation.

Many air compressor applications include a combination of machines, which often requires a phase converter to accommodate a wide range of load conditions. The Phasemaster rotary three-phase converter is ideally suited to these requirements and maintains a balanced output condition under both light and heavy load demands. As with other applications, the Kay Industries approach to phase converter sizing is very methodical, taking special care to match the proper three-phase converter to your load.

Many air compressor applications are unattended. That means they cycle on and off at various intervals according to the demands of the pressure switch. Phase converters for these types of unattended installations should be specified to include automatic controls so that the converter can be shut down when the compressor is not running.

The Phasemaster rotary phase converter has been tested, approved, applied on or recommended by some of the best known manufacturers of air compressors.


Known Operating Issues:

Air compressors can be among the most onerous loads to start, particularly if they are not equipped with unloading mechanisms to reduce allow the motor to start without pumping against the tank or head pressure of the compressor. An unloader is especially important if the compressor is called upon to keep up a rather high tank pressure (for example 100PSI or greater). In addition, it is imperative the utility supply voltage remain solidly within a few percent of its unloaded value. A “soft” utility supply where the supply voltage drops by 10% or more could cause the compressor motor to stall or trip an overload. Increasing the size of the converter by one rating above the motor size will usually fix the problem but is not an economical substitute for an unloader or a solid utility service.


Critical Selection and Application Criteria:

• Be sure to have adequate single-phase service. You must have at least 5amps of single-phase service for each 1HP of connected 3-phase load at 230 volts.

• Identify what machines will operate together. If the largest load is more than four times the HP of the smallest load, a voltage regulator should be installed in the converter.