Product Manual

Operation
26 900-0145-01-01 Rev B
functions, all of which are operated by the MATE3 system display. (See page 47.) Another example is the
MATE3’s
AC INPUT
hot key menu, which can order all inverters to disconnect when set to
Drop
.
Generator Input
A generator should be sized to provide enough power for all inverters, both for loads and for battery
charging. The generator’s voltage and frequency must match the inverter’s acceptance settings.
It is usually recommended that the generator be sized at twice the wattage of the inverter system.
Many generators may not be able to maintain AC voltage or frequency for long periods of time if they
are loaded more than 80% of rated capacity.
The generator is required to have a stable output before its power is accepted by the inverter. Some
generators with less stable or uneven outputs may not be accepted. The use of the
Generator
input
mode may assist with this problem.
Transfer
The inverter uses a transfer relay to alternate between the states of inverting and of accepting an AC
source. Until the relay energizes, the output terminals are electrically isolated from the input that is in
use. When it closes, the input and output terminals become electrically common. (The terminals for
the unused input remain isolated during this time.) When the relay changes states, the physical
transfer delay is approximately 25 milliseconds.
The relay contacts are limited to 50 amps per phase or leg. The continuous loads on that output
should never exceed this number. When connected to an AC source, the Radian inverter cannot limit
the load current. An overload condition is possible.
CAUTION: Equipment Damage
Current draw in excess of the transfer relay rating can damage the transfer relay. This
damage is not covered by warranty. Use protective devices of appropriate size.
The inverter does not filter or clean up the power from the AC source. The voltage and power quality
received by the output loads is the same as that of the source. If the voltage or quality do not meet
the inverter’s input requirements, it will disconnect and return to the inverting mode.
NOTES
:

To ensure a smoother transition, it may be advisable to raise the inverter’s lower acceptance limit.
The default setting is 208 Vac. A higher setting will cause the inverter to transfer sooner in the event of a
quality problem.

If the AC source meets the inverter’s requirements but is irregular, any fluctuations will be transferred to the
loads. If the loads are sensitive, it may be necessary to improve the quality of the AC source.

The
Generator
input mode is intended to accept irregular or unfiltered AC sources and is more likely to do
so than other modes. This should be considered before using this mode with sensitive loads. (See page 13.)
If the charging function is turned off, the inverter will transfer power from the source but will not use it
to charge. If the inverting function is turned off, the inverter will transfer (“pass through”) the source
power when connected, but will not invert when the source is removed.
In a stacked system, slaves are ordered to transfer at the same time as the master. If a slave does not
sense an AC source at the same time as the master, it will continue inverting, and will experience a
Phase Loss
warning (see page 58). This appears as an Event on the MATE3 system display.