User`s manual

4
e. High frequency design: The inverter uses high frequency, high efficiency IGBTs, and PWM to convert
the DC power to AC power. The number of components is reduced, resulting in increased reliability,
smaller size and weight, less transportation cost, improved performance, and the elimination of
acoustic noise.
f. True Galvanic isolation: An isolation transformer is used at the output. This solves the problem of
poor input grounding and will accept a different ground between input and output. Ground the output
to a known earth connection. This avoids the annoying problem of ground leakage current and allows
the output to be tied to any potential provided on site. The AC output is isolated under every mode of
operation. In addition common mode noise from the output isolation transformer is attenuated.
g. Modular design: The power circuit is separated into several modules plugged into slots in the UNIT,
which are easy to remove, permitting quick maintenance and easier trouble shooting (before the DC
bus is energized).
h. Multi-CPU design: Several CPUs are employed in the control circuit, critical functions are designed in
parallel to improve reliability. Therefore, in case of one CPU fails; the other CPUs can assume control
to maintain the output AC.
i. Operator errors: The UNIT is designed with breaker on/off sensors, power supply sensors, etc. to
prevent user errors from damaging the UNIT.
j. Wide input range: The UNIT is designed to accept an extra wide input range, so that it can work
comfortably under poor AC source conditions. Also, all the input components used are specially
selected to handle extreme high voltage and high current.
k. Extreme environment: Each component of the UNIT is chosen with a large safety margin to accept
extreme environmental conditions, such as temperature, humidity, altitude, shock, and contamination.
l. Extended MTBF of fans: Fans will slow down under light load, so that the life expectancy of the fans is
longer than specified.
m. Data log capability: Every abnormal condition will be stored in the converter for further reference. The
data is stored with the date and time (with a real time clock). When an abnormal condition occurs, the
user can get a full record of what has occurred. The data will not be erased even when all the power is
switched off.
n. Convenient panel design: The LCD display control switch is accessible through the up/down/enter
switch on the front window, which means one can read all the UNIT data without opening the front
door. Of course, the important inverter on/off switch is hidden behind the door (a key is needed to
open it, but you can also switch the inverter on or off from the front window by entering the correct
password in case the key is not at hand or lost), so that it is not easy to accidentally switch the UNIT on
or off.