We present the following
information in an
effort to reduce
the complexity of the generator
selection process by
identifying a few key questions and providing answers that
are as
simple as the subject matter
allows. In no way is
the information
presented here intended to be an
exhaustive treatment of the
topic.
Q.
What’s
the single most important thing I should consider when buying a
generator?
A.
Without a doubt,
the most crucial piece of information that you
need to know is how much electrical power you will need in your
specific situation. Nothing will be more
disappointing to you than buying a generator that does not produce
adequate power for your needs.
In order
to choose the right emergency power source
and to size it properly, you need to understand something about the
power requirements of the devices you plan to
operate.
The basic
unit of power measurement is the watt, and
with an emergency power source there are two wattage ratings that
are important: steady-state wattage and
surge wattage. A normal 60-watt incandescent light bulb requires, as
you would expect, 60 watts, and it
requires that wattage both when you turn it on and while it is running.
A ceiling fan motor, on the other hand, might require
150 watts to get it started and 75 watts while it is
running. That extra wattage to start the motor is called the surge
wattage and is typical of anything that contains
an electric motor. Here are the usual wattages of some of the
devices
found in a typical household:
One other thing to note is
that if you
plan to
operate sensitive equipment like TV’s and computers from an
emergency
power supply, you will want to have
in place excellent surge protection equipment and, in the case of a
computer, an uninterruptible power supply (UPS).
When a large device like a refrigerator turns on, there is no way that
a small generator will be able to keep power stable during
the
surge. UPS will prevent your computer from
crashing during the blip.
Q.
How do I calculate my power needs?
A.
To calculate
your power needs, you need to add up the normal
and surge wattage figures for all of the devices you want to operate
simultaneously. Here is an example
based on the
previous table:
If
you plan to operate your refrigerator, a colour TV and a microwave
simultaneously, you need 2,250 watts continuous and 3,800 watts surge
in the worst
case (if all three happen to
turn on at exactly the same moment). If you are willing to
manage your power a bit and make
sure they do
not all turn on at once, then your surge power requirement is only
2,400 watts. If you are willing to operate
only one of these devices at a time, then, because your refrigerator is
the largest power user, you need to size your
emergency power system so it is large enough to handle the
refrigerator.
Q.
What is the
difference between a Stand-By and a Prime Power generator?
A.
It is important
to decide whether you need a stand-by or prime
power generator. Simply stated, prime power is required when you have
no
other source of power. A stand-by
generator is a back-up to normal utility power.
Q.
Do I require
Single or Three-Phase power?
A.
Generator
sets produce either single or three-phase
power. Choose a single-phase set if your motors are five
horsepower or
less. Three-phase power is better for
motor starting and running. Most homeowners require single
phase
(for
small units of 7.5KVA or less), whereas
industrial or commercial applications usually require three-phase
power. Three-phase generators are set up to
produce 231/400 volts. Single-phase sets are 120/240. Use the low
voltage to run domestic appliances and the high
voltage for your motors, heaters,
stoves and dryers.
Q.
What are the
major parts of a generator?
A.
There are
four major components of a generator: the engine
which provides the mechanical power, the alternator which is
attached to the engine and
turns the
mechanical energy into electricity, an output/control panel which
provides a place for the electrical
outlets (receptacles), circuit breakers, and controls (switches), and a
metal frame to hold the whole thing together. In addition to
these four
major components, there may also be
a fuel tank separate from the engine and often mounted on top of the
frame.
Q.
What do I need
to know about engines?
A.
Your first
concern should be the types of fuel they can
use. Generators are available with engines that run on gasoline, diesel
fuel, liquefied propane (LP) gas, or
natural gas.
We recommend diesel
generators
due to their
longevity and lower operating costs. Today’s modern diesels
are
quiet
and normally require much less maintenance
than
comparably sized gas generators. Fuel costs per kW produced with
diesels are normally 30% to 50% less
than gas units.
With engines, the
second thing
you need to think
about is the brand name. Choose one that you know and trust. For large
units, we recommend Volvo engines –
the brand
is well known, reliable, and offers a twelve month (or 2 000 running
hours) guarantee. In addition, the support
structure and service network for the brand is superb.
Q.
What do I need
to know about alternators?
A.
The alternator
is the "business end" of the generator and
actually produces the electricity, so it’s important to look
for an
alternator that is built to last. Look for an
all-metal design because plastic housings can warp over time and cause
the moving parts of the alternator to come
out of alignment and break or wear excessively. Get an alternator that
uses "ball bearings" instead of "needle bearings;" it will last longer.
"Brushless" designs require less
maintenance and produce cleaner power that is more suitable for
electronic
equipment.
We recommend
Engga alternators
for the above reasons, especially for larger generator sets.
Q.
How are the
generators protected from overload?
A.
All generators
feature AC circuit breakers. In the event the unit
is overloaded, the circuit breaker will pop out. If this happens, the
operator needs to
correct the overload
condition and then reset the circuit breaker by pressing it back in
again.
Q.
Can I run the
generator inside my home?
A.
NO! A generator
has an internal combustion engine and uses
gas and oil. The exhaust from running the generator contains lethal
carbon monoxide. Therefore, this
unit should
always be placed in a well ventilated area.
Q.
Can the
generator be used during inclement weather?
A.
Generators
obviously are used in a wide variety of weather
conditions, but they should be protected from the elements to prevent
shorting and rusting. Protection
for the
unit must be provided in a manner that does not impede the air flow to
the unit needed for cooling both the engine
and generator head.
Our quotes for
generator sets include
Weather-Proofing for the above reasons, though open sets are also
available.
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