LS SV-xxx-iP5A-2, Руководство пользователя

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Chapter 9 Applying Drives to Single-Phase Input Application
9-
２
9.2 Power(HP), Input Current and Output Current
When using a three-phase VFD with single-
phase input, derating the drive’s output current
and horsepower will be necessary because of the increase in DC bus ripple voltage and
current. In addition, the input current through the remaining two phases on the diode bridge
converter will approximately double, creating another derating consideration for the VFD.
Input current harmonic distortion will increase beyond that with a three-phase supply making
the overall input power factor low. Input current distortion over 100% is likely under single-
phase conditions without a Reactor. Therefore, the Reactor is always required. When using
a motor that is selected by the three-phase drive rating criteria when using single-phase
input, it may result in poor performance, premature drive failure.
The selected drive of single-phase current ratings must meet or exceed the motor current
ratings as indicated in Table 1.
9.3 Input Frequency and Voltage Tolerance
The drive ratings in Table 1 are valid for 60Hz input only. Operation at input frequencies
other than 60Hz will require further review by LSIS.
The AC supply voltage must be within the required voltage range of 240/10% to
–5%
to maximize motor power production. Standard product with three-phase voltage input as 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 )
9.4 Wiring and Peripheral Device
It is important that input wiring and branch circuit protection be selected based on the drive’s
single-phase input current rating indicated in Table 1-2.
The single-phase input current after derating differs from the three-phase input indicated on
the VFD nameplate. Connect single-phase AC input wiring below Figure-3 (R(L1)-T(L3)).