Standby Mode; Figure 3-2, Power Flow - Standby Mode - Magnum Energy MS-PAE Series Owner's Manual

3.2 Standby Mode

The MS-PAE Series features an automatic transfer relay and an internal battery charger when
operating in the Standby Mode. The Standby Mode begins whenever AC Power (Utility or Genera-
tor) is connected to the inverter's AC input. Once the AC voltage and frequency of the incoming
AC power is within the AC input limits, an automatic AC transfer relay is activated. This transfer
relay passes the incoming AC power through the inverter to power the AC loads on the inverter's
output. This incoming power is also used to activate a powerful internal battery charger to keep
the battery bank charged in case of a power failure. Refer to fi gure 3-2 to see the fl ow of power
from the AC input to the DC and AC output while in the Standby Mode.
AC
IN
AC H OT 1 IN
240
VA C
120
VAC
120 AC H OT 2 IN
VAC
AC N EU T R AL
D C
D C N EGAT IVE
OU T
D C POSIT IVE

Figure 3-2, Power Flow - Standby Mode

3.2.1 Battery Charging
Magnum Energy's MS-PAE Series is equipped with an active PFC (Power Factor Corrected) and PI
(Proportional-Integral) multistage battery charger. The PFC feature is used to control the amount
of power used to charge the batteries in order to obtain a power factor as close as possible to 1
(or unity). This causes the battery charger to look like a resistor to the line (forces the charge
current waveshape to mirror the voltage waveshape). The PI feature allows the charger voltage
and current to change independently. These two features maximize the real power available from
either utility or generator AC power sources, which translates into less power wasted and greater
charging capabilities than most chargers available today.
When an AC source is connected to the AC input, the inverter begins monitoring for acceptable AC
voltage. Once the inverter has accepted this AC voltage, the AC transfer relay closes and the Charge
Mode begins. After Charge Mode begins, the DC voltage is monitored to determine the charging
stage. If the DC voltage is low (≤ 25.6 / 24-volt models or ≤ 51.2 / 48-volt models), the charger
begins Bulk Charging. If the DC voltage is high (>25.6 / 24-volt models or >51.2 / 48-volt models),
the charger will skip the Bulk and Absorb charging stages and go directly to Float Charging.
The multistage charger can use up to fi ve different charging stages to help monitor and keep the
batteries healthy; The fi ve stage include an automatic 4-stage charging process: Bulk, Absorb,
Float and Full Charge; and a manual Equalization (EQ) charge stage. The automatic 4-stage charge
process provides complete recharging and monitoring of the batteries without damage due to over
charging. The EQ stage (requires the ME-RC remote to enable Equalization charge) is used to stir
up stratifi ed electrolyte and try and reverse battery plate sulfation that may have occurred.
While charging, the unit may go into Charger Back-off protection, which automatically reduces
the charge current to the batteries. This is caused by: 1. The internal temperature is too hot - the
charger automatically reduces the charge rate to maintain temperature; or 2. The AC input volt-
age falls below 170 VAC (or 85 VAC on either leg) - the charger will stop charging to help stabilize
the incoming AC voltage.
© 2009 Magnum Energy Inc.
AC T ransfer R elay
C B 3 (30A )
C B 2 (30A )
AC
D C
F ET Bridge
Pow er T ransform er
Operation
AC
OU T
240
AC H OT 1 OU T
VA C
120
VAC
120
AC H OT 2 OU T
VAC
AC N EU T R AL
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