Samlexpower PSE-12125A, Owner'S Manual

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6 | SAMLEX AMERICA INC. SAMLEX AMERICA INC. | 7
loads that Require “Surge Power” to Start
resistive types of loads (like incandescent lamps, toaster, coffee maker, electric range,
iron etc) do not require extra power to start. Their starting power is the same as their
running power. Some loads like induction motors and high inertia motor driven devices
will initially require a very large starting or “surge” power to start from rest. once they
have started moving and have attained their rated speed, their power requirement
reduces to their normal running power. The surge may last up to 5 seconds. TVs and
microwave ovens also require surge power for starting. The manufacturers’ specification
of the appliances and devices indicates only the running power required. The surge power
required has to be guessed at best. See below under “Sizing of inverter for loads that
require starting surge.”
If an inverter cannot efficiently feed the surge power, it may simply shut down instead
of starting the device. If the inverter’s surge capacity is marginal, its output voltage
will dip during the surge. This can cause a dimming of the lights in the house, and will
sometimes crash a computer.
Any weakness in the battery and cabling to the inverter will further limit its ability to
start a motor. A battery bank that is undersized, in poor condition, or has corroded
connec-tions, can be a weak link in the power chain. The inverter cables and the battery
interconnect cables must be sized properly. The spike of dc current through these cables
is many hundreds of amps at the instant of motor starting. Please follow the instructions
under “Installation - dc Side connections" on page 25.
Sizing of inverter for loads that Require Starting Surge
observe the following guideline to determine the continuous wattage of the inverter
for powering loads that require starting surge.(Multiply the running watts of the device
/ appliance by the surge factor). note: the surge power rating specified for the inverter
is valid for duration of less than 2 seconds. this very short duration may not be suf-
ficient to start motor based loads which may require up to 5 seconds to complete the
starting process. Hence, for purposes of sizing the inverter, use only the continuous
power rating of the inverter.
type of Device
or Appliance
Surge Factor for Determining continuous Wattage of the inverter
(no. of times the running power rating of the device/appliance)
refrigerator / freezer 5
Air compressors 4
dishwasher 3
Automatic washer 3
Sump pump 3
furnace fans 3
Industrial motors 3
Portable kerosene /
diesel fuel heater
2
circular saw / bench grinder 3
Incandescent / halogen /
Quartz lamp
3
seCtIOn 2 | General Information on Inverters