Samlex America SAM-800-12 - Manuel (Page 17)

14 | SAMLEX AMERICA INC. SAMLEX AMERICA INC. | 15
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info
it is normal for the alarm to sound while the unit is being connected to or discon-
nected from the power source. this is not indicative of a problem.
Ground fault protection - General
Due to loss of insulation as a result of aging of insulating materials, accident or malfunc-
tion, voltage source inside an electrical device can get connected to its metal chassis. If the
energized metal chassis is touched by a person standing on earth Ground (considered to
be at 0V), they will get a shock due to current leaked through the body to earth Ground
(called Leakage Current). Such condition is called “Ground fault”. As this Leakage Current
is diverted to earth Ground, it does not return to the electrical power source supplying
the AC device. Severity of electrical shock will depend upon the value of the fault voltage
on the metal chassis and the impedance in the current path to earth Ground, primarily the
impedance of the human body (100 kΩ when dry and 1 kΩ when wet). Human body can
tolerate leakage current of up to 5ma for 15 to 30 msec.
Ground fault protection in this inverter is provided as follows:
• The Line and Neutral terminals of the AC outlet are isolated from its grounding ter-
minal. Thus, the metal chassis of the AC loads will also be isolated from the Line and
Neutral.
• The grounding terminal of the AC outlet is connected to the input section of the elec-
tronic Ground fault Protection Circuit on the power circuit board.
• Due to the above implementation, the neutral voltage will be pulsing Dc voltage
with average Dc value of up to 50 VDc with respect to the metal chassis of the ac
loads / metal chassis of the inverter (will read 75 Vac on the ac scale of the Voltmeter
because of pulsing nature of Dc Voltage). Similarly, the Line voltage will also be up to
75V with respect to the metal chassis of the ac loads / metal chassis of the inverter .
Do not touch the Line / neutral!
• If the metal chassis of the load develops a Ground Fault condition, up to 75V will be
fed to the electronic Ground fault Protection Circuit and the AC output of the inverter
will shut down.
• Ground fault protection will also operate if the neutral and ground of the ac output
of the inverter are connected (bonded) intentionally like in Service entrance / Load
center for ac distribution wiring.
!
caution!
Connecting to utility AC distribution wiring with Neutral to Ground connection (bond)
is not permitted. In AC utility distribution wiring, the Neutral conductor is connected
(bonded) to the equipment Grounding Conductor at the Load Center / Service entrance.
both these conductors are then bonded to the earth Ground (Ground rod). Thus, if the
output of the inverter is connected to the utility AC distribution wiring, it will see a Neu-
tral to Ground connection and the inverter will trip due to activation of the Ground fault
Protection Circuit as explained above.
SECTION 6 | Protections Monitoring
& Troubleshooting