Theory Of Operation - Vector MAXX SST 3000 VEC051 Owner's Manual

CAUTIONS:
This device supplies 110 VAC electrical power directly to the appliances
through two standard, North American 3 conductor receptacles and through
the output hard-wire terminal block. The circuit connected to the High Output
Terminal Block requires a dual ganged 30 amp circuit breaker (not included).
See Figure 1 to locate the High Output Terminal Block. Installation of external
wiring is described in section 5.6. NEVER try to use the inverter with any 12
VDC power source that uses a positive ground. Most modern vehicles, boats,
and aircraft use negative ground systems.
Do not connect the ground wire from the inverter to the DC negative input.
• CHECK to ensure that the combined loads of the appliances being powered
MAXXSST 3000
™
by the inverter DO NOT continuously exceed
3000 watts.
• NEVER place items on or over the inverter during operation.
The inverter generates heat during operation like any high power device and it
must be placed where cooling air can be drawn into the unit by its internal fan,
and heated air can be expelled and dissipated. For optimum operation, the
inverter should be placed or mounted on a flat surface; ideally, a normally cool
metal surface to help diffuse the heat that is generated. Two cables and a fuse
rated at 500 amps will be required (not supplied).
For safety reasons, keep small children away from the inverter.
5.3 Installation Sequence
To wire the inverter to a 12 VDC power source, observe the following cautions
and follow the installation sequence for Quick Operational Checkout and
Permanent Installation. External AC wiring is described after all DC wiring proce-
dures and tests are accomplished.
CAUTIONS:
Ensure that DC connection polarity is correct. Reversed polarity will blow a fuse
and may cause permanent damage to the inverter. The manufacturer's warranty
does NOT cover damage due to reversed polarity. Review Figure 2, if
necessary, to identify the location of the DC terminals.
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When outside AC power is restored, the transfer switch should be returned
to the outside AC position. This off-loads the inverter and allows for faster
battery recharging.
Use the same charging guidelines in the previously described UPS (floating battery)
configuration.
You may have to contact an electrical supply house and/or your electrician to
install a transfer double-pole, double-throw ganged transfer switch rated at 30
amperes AC or greater. Both the Neutral and Hot must be simultaneously switched
to ensure that Neutral is NEVER connected to ground.
Common unattended applications for UPS (floating battery) and automatic transfer
switch configurations are for powering: sump pumps, safety lighting, communications
equipment, burglar alarm systems and computer systems. If a transfer switch is
used, computers should be also powered by a small capacity uninterruptible power
supply (UPS) to "ride through" the period that power is lost during the transfer delay.
If outside AC will not share an AC power distribution system with the Power Force
Inverter, the transfer switch configuration can be disregarded.
The UPS "floating battery" configuration can be used if uninterrupted AC power is
a requirement, regardless of whether direct wiring or inverter AC outlet plug-in
connections are used to power appliances.
3.0

THEORY OF OPERATION

The inverter changes 12 VDC into 110 VAC RMS, electrical power. This is
accomplished in two steps. See FIGURE 5. The first step raises the 12 VDC input
to 145 VDC. The advanced design of the DC-to-DC first stage uses modern
high-frequency conversion techniques that supersede bulky and heavy transformers
found in older, less technologically-advanced inverters. The output stage changes
the 145 VDC to 110 VAC. This solid-state circuitry ensures excellent overload
protection and the ability to operate reactive loads such as those found in
inductive motors.
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