Magnum Energy MSH-M Series - Manual (Page 43)

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©
2013 Magnum Energy, Inc.
Operation
Figure 3-7, MSH Current Flow – Load Support AAC
MSH Inverter
AC Loads
(Large)
+30A
DC Current
(Battery)
-10A
AC Current
(Grid/Gen)
-20A
Load Support AAC – If AC loads are added that are above the capability of the grid/generator,
the MSH converts current from the battery and combines it with the current from the grid/
generator to power the additional AC loads.
Figure 3-8, MSH Current Flow – Load Support VDC
MSH Inverter
AC Loads
(Large)
+30A
DC Current
(Battery)
-20A
AC Current
(Grid/Gen)
-10A
Load Support VDC – If the battery is being charged externally (i.e., solar, wind, or hydro), the
MSH converts any excess current from the battery to power the AC loads and reduce the current
from the grid/generator.
3.4 Transfer Time
While in Standby mode, the AC input is continually monitored. Whenever AC power falls below
the VAC dropout voltage (80 VAC, default setting), the inverter automatically transfers back to
Inverter mode with minimum interruption to your appliances—as long as the inverter is turned
on. The transfer from Standby mode to Inverter mode occurs in approximately 16 milliseconds.
While the MSH-M Series is not designed as a computer UPS system, this transfer time is usually
fast enough to hold them up. However, the VAC dropout setting has an effect on the ability of the
loads to transfer without resetting. The lower this setting, the longer the effective transfer will be
and therefore, the higher the probability for the output loads to reset. This occurs because the
incoming AC voltage is allowed to fall to a level that is so low that when the transfer does occur,
the voltage on the inverter’s output has already fallen low enough to reset the loads.
The disadvantage of a higher VAC dropout setting is that smaller generators (or large generators
with an unstable output) may nuisance transfer. This commonly happens when powering loads that
are larger than the generator can handle—causing the generator’s output voltage to constantly
fall below the inverter’s input VAC dropout threshold.
Info: When switching from Inverter mode to Standby mode, the inverter waits
approximately 15 seconds to ensure the AC source is stable before transferring.