Applying Drives to Single-Phase Input Application
12.3 Input Frequency and Voltage Tolerance
The single-phase current ratings are valid for 60Hz input only. The AC supply voltage must
be within the required voltage range of 240/480Vac +10% to –5% to maximize motor power
production. Standard product with three-phase voltage input has an allowable range of +10%
to –15%. Therefore, a stricter input voltage tolerance of +10 to –5% applies when using the
drive with a single-phase supply. The average bus voltage with single-phase input is lower
than the equivalent of a three-phase input. Therefore, the maximum output voltage (motor
voltage) will be lower with a single-phase input. The minimum input voltage must be no less
than 228Vac for 240 volt models and 456Vac for 480 volt models, to ensure motor voltage
production of 207Vac and 415Vac, respectively. Thus, if full motor torque must be
developed near base speed (full power) it will be necessary to maintain a rigid incoming line
voltage so that adequate motor voltage can be produced. Operating a motor at reduced
speed (reduced power), or using a motor with a base voltage that is lower than the
incoming AC supply rating (ex. 208Vac motor with a 240Vac supply), will also minimize the
effect of voltage deprivation. ( 240VAC Input 208V motor, 480VAC Input 400V motor )
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