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SECTION 5 |
ATTenTIon!
Dans la condition normale, le neutre de la sortie CA de l'appareil
dans la mode « Onduleur» est lié au châssis métal de l'appareil
par le relais de changement du neutre au châssis interne «Neutral
to Chassis Switching Relay».
Dans la mode «Utilitaire/Générateur», le «relais de changement
du neutre au châssis» interne va déconnecter le neutre de la
connexion de sortie CA et le châssis de l'appareil. Le neutre de la
connexion de sortie CA de l'appareil serait lié à la mise à la terre,
à travers le liason du neutre et la mise à la terre, qui existe à
l'entrée de service/connexions de sortie CA du générateur.
C'est la responsabilité de l'utilisateur ou ceux qui installe le
système, de mettre le système à la terre, qui est réquis par les
Normes Nationales/Locales Électriques.
AC Transfer and Ground-To-neutral bond
Switching In G4 Series
As required by NEC and UL specification 458, inverter / charger
installations in the U.S. that are used in Rv or Marine applications should
be provided with a "Neutral to Ground Bond Switching Relay" to switch
bonding of the Neutral Output Connector of the Inverter Charger as
follows:
• When operating as an inverter, the current carrying conductor of
the Inverter Section that is connected to the Neutral Out connector
of the Inverter Charger should be bonded to the metal chassis of
the inverter by the "Neutral to Ground Bond Switching Relay". As
the metal chassis of the inverter is in turn bonded to the Rv Ground
(chassis of the Rv) or to the Boat Ground (DC Negative Grounding
Bus Bar and the Main AC Grounding Bus Bar are tied together in
a boat and this is called the "Boat Ground"), this current carrying
conductor of the Inverter Section will become the Grounded
Conductor (GC) or the Neutral of the Inverter Section. This meets
NEC requirements
• When in the Utility / Generator Modes, the Neutral of the shore
power will be connected to the Neutral Out connector of the Inverter
Charger. At the same time, the "Neutral to Ground Bond Switching
Relay" will unbond (disconnect) the Neutral Out connector of the
Inverter Charger from the chassis of the Inverter Charger. This will
ensure that the Grounded Conductor (GC) / Neutral of the shore
power is bonded to the Earth Ground at one single point at the
location of the AC Power Distribution System of the Marina/Rv Park.
• In some marine applications, Neutral-to-Ground switching is not
required or acceptable. The potential for galvanic corrosion caused
by small leakage currents between boats with dissimilar metals is
present. The proper and safe ways to prevent this is by using galvanic
isolators or include an isolation transformer for the AC input.
Disconnecting the common ground between the AC and DC system
could contribute to a hazardous and potentially fatal situation.
Please read the following on-line white Papers for more details
at www.samlexamerica.com (Home > support > white Papers):
28 | SAMLEX AMERICA INC.
Installation
-
"grounded electrical aC Power distribution"
-
"grounding system and lightning /
ground Fault Protection"
-
"neutral to ground switching in rV and
Marine applications"
Schematic at Fig. 5.10, page 29 explains implementation in the G4 series.
The bi-directional Transformer is used as follows:
• Feeds AC output from the Inverter Section when shore power is
not available.
• Feeds utility / shore power to the Battery Charger Section when
shore power / utility is available.
Switching of Hot output (HoT oUT)
• Relays K1 and K4 are rated at 40A each and operate in parallel
(effective capacity of 80A). These are used to switch the Hot Output
Connector (HOT OUT) to either the Inverter Section or to the Utility /
Shore Power
• When Utility / Shore Power is available, relays K1 and K4 are
energized and contact 4 switches over to contact 5. The Bi-
directional Transformer works as a battery Charger. The Hot AC
input (HOT IN) from the shore power is fed to the Hot input of the
Bi-directional Transformer for battery charging and at the same time,
it is fed to the Hot Out (HOT OUT) for powering the load
• When Utility / Shore Power fails, relays K1 and K4 are de-energized and
contact 4 switches over to contact 3. The Bi-directional Transformer
operates as an inverter. Hot AC output from the Bi-directional
Transformer is fed to the Hot Out (HOT OUT) for powering the load
Switching of neutral to Ground bonding
• Relays K2 and K3 are also rated at 40A each and operate in parallel
(effective capacity of 80A). These are used to switch the bonding of
the Neutral Out Connector (NEU OUT) to the chassis of the G4
• When Utility / Shore Power is available, K2 and K3 are energized
and contact 4 switches over to contact 5. The Bi-directional
Transformer works as a battery Charger. AC input Neutral (NEU
IN) from the shore power is fed to the Neutral input of the Bi-
directional Transformer for battery charging and at the same time it
is connected to the Neutral Out (NEU OUT) for powering the load.
The Neutral Out (NEU OUT) is isolated from the chassis of the G4
• When Utility / Shore Power is removed, K2 and K3 are de-energized
and contact 4 switches over to contact 3. The Bi-directional
Transformer operates as an inverter. One of the current carrying
conductors of the Bi-directional Transformer that is connected to
contact 4 is now bonded to the chassis of G4 through contact 3.
This conductor now becomes a Grounded Conductor (GC) or
Neutral. At the same time, the Neutral out of the Bi-directional
Transformer is connected to the Neutral Out (NEU OUT). The Neutral
out (NEU OUT) is bonded to the chassis of G4.
AC Input Considerations –
Voltage And Frequency
The G4 unit is designed to accept 120 vAC, 60 Hz / 50 Hz single phase
AC power from utility or generator. The 120v versions come preset for
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