Product Manual
72 | SAMLEX AMERICA INC.
- When the unit powers up, it starts in Inverting Mode rst. The output voltage ramps
up gradually from around 48 VAC to 120 VAC in around 200 ms. This reduces
otherwise very high starting inrush current drawn by AC loads like Switched Mode
Power Supplies (SMPS) and motor driven loads like fans, pumps, compressors etc. This
will result in lower motor inrush current (which typically can be up to 650% of the full
load current of the motor), which means lesser mechanical stresses, wear and tear and
increased lifetime of the motor, coupling and fan. Additionally, the impact on the load
side components is greatly reduced, meaning less likelihood of causing problematic
voltage drops during starting.
Power Surge – Up to 300%:
- The inverter is able to deliver very high surge power / current of up to 300% for 1 ms
followed by 200% for 100 ms. This range of high instantaneous power is delivered at
the rated voltage and hence, it is able to provide very high starting torque for difcult
motor driven loads like compressors and pumps that require higher Locked Rotor
Current during startup.
-
If the power drawn by the load exceeds the above surge ratings, the inverter pr
otects
itself by limiting the load current to 300% / 200% which results in reduction of
output voltage and consequent reduction in load current. The output voltage recovers
automatically when power drawn by the load drops below the above surge limits
Power Boost up to 150%: Higher percentage of rated power can be provided for limited
time periods as follows:
•
150% for 30 sec
•
140% for 1 min sec
•
120% for 10 min
• 110% for 30 min
4.4 TRANSFER RELAY SECTION
Transfer Relay Section is used to either feed AC power to the Battery Charger Section and at the
same time, pass through the AC power from the external AC input power source to the load (As
long as the external AC input power is available and is within the programmed limits of voltage
and frequency) or to transfer the load to the Inverter Section (In case of loss of the external AC in-
put power source or if this source is not within the programmed limits of voltage and frequency).
Typical transfer time is 16 milliseconds from Grid/Generator to Inverter and <1ms from Inverter to
Grid / Generator. Heavy duty 30A. Transfer Relay (RY1, Fig 4.1) is used for reliable transfer of up to
300% surge power. A separate Relay (RY2, Fig 4.1) is used for Neutral to Ground Bond Switching.
4.4.1 AC Transfer and Output Neutral To Chassis Ground Bond Switching
As required by NEC and UL Standard 458, automatic switching of bonding between the Output
Neutral and Chassis Ground has been provided in EVO
TM
through “Output Neutral to Chassis
Ground Bond Switching Relay” (RY2 in Figs 4.1). Switching of bonding is carried out as follows:
• When operating as an inverter, the current carrying conductor of the Inverter Section that is con-
nected to the Output Neutral terminal of EVO
TM
is bonded to the metal chassis of EVO
TM
by the
“Output Neutral to Chassis Ground Bond Switching Relay” (RY2 in Figs 4.1). As the metal chas-
sis of EVO
TM
is in turn bonded to the Earth Ground (in shore installations) or 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
SECTION 4 | General Description & Principles of Operations