The majority of motors used in air conditioning and refrigeration equipment for 208 volt and 240 volt distribution systems are extended voltage 208/230 volt motors. 208/230 volt single-phase motors are generally limited to operation at 197 volts under Emerson Climate Technologies' maximum design load conditions for compressors, while 208/230 volt three-phase motors are generally limited to 187 volts under similar maximum load conditions. At times, engineers who are primarily familiar with NEMA rated single voltage motors jump to the conclusion that a 200 volt nameplate is a better motor for low voltage conditions. Such a conclusion is not necessarily true. Since Emerson maximum design load standards for compressors are quite conservative, compressors operating at normal load conditions found in systems are capable of operation at voltages far below the normal tolerance of minus 10% of the nameplate. Field experience further supports the conclusion that the extended voltage motor, because of its stronger winding construction, is capable of operating far below normal voltage conditions for extended periods without adverse effects.
...
The operating voltage range listed is for Emerson's maximum load design conditions for compressors. These conditions are normally more severe than those experienced by compressors operating in systems at system maximum load conditions. More specifically, compressors which meet these standards will normally operate satisfactorily at the system conditions and voltages required by ARI Standard 110.
...
{operating voltage range at max load design conditions}
208/230-1: 188-253V semi-hermetic and scroll
208/230-1: 197-253V hermetic (welded)
208/230-3: 187-253V