[KYHAM] KEN TRAINING for April 29: How to choose the proper generator…

[Ron Dodson]

How to choose the proper generator…
Anthony Whobrey, KC4JTV

For those of you who have considered the purchase of a
stand-by or emergency electric generator, there are a few
points to consider before bringing one home.

First, decide on a budget for the unit… it will always cost
a little <or a lot > more than you plan on. Give thought to
how many times in the past year or so that you have been
without electricity and the duration of the outage. Do you
really need a 25 KVA unit that will run your entire home, or
will a smaller 4 or 5 kW unit serve your needs? It is
certainly nice to have a large standby unit, with automatic
transfer and weekly tests, but is it worth the expense?
Perhaps if you have the resources available and your job
like my own could require that you be away from your
residence during an emergency, a fully automatic system
could be desirable. A few vendors offer standby units
designed for residential use; these units are usually around
12-20 KVA and about the size of a 2-ton air conditioning
unit. Powered by propane or natural gas, with a high RPM
air-cooled engine, these units are generally acceptable in
areas with infrequent outages. If you are subject to
frequent, lengthy outages you will need a low RPM diesel
powered unit; these sport a hefty price tag, since they are
not generally used for residential service.

If you will be home during an outage, you have other
options. Once again, consider how often you are affected by
an outage, and the effects of it. Determine which loads in
your home must be supported at the same time; add the rated
wattage of all the devices together. Some devices require
quite a bit more than rated current when starting, this
should not present a problem since it is assumed that you
will not be starting all the loads at the same time. If this
figure is over 5000 watts then consider the purchase of a
stationary unit with a manually operated transfer switch; it
is difficult to safely supply a load of this size with
extension cords. At least one vendor offers a small transfer
switch designed for residential use; the price is not too
much more than the cost of several good extension cords.

Assuming a figure in the 3500-4000 watt range, multiply by
1.25, this will give your generator an 80% load.
Unfortunately, most of the units sold at retail stores are
over-rated, that “5000 watt” unit really doesn’t want much
more than 4000 watts of load.

Now try to realistically decide how often the unit will be
needed; are outages frequent or lengthy in your area? Maybe
you can’t really remember the last time the power was off,
and just want a unit for “insurance”. If that is the case,
look at the wattage figure you have, go down to your
favorite lawn and garden store and pick up that size unit.
Almost any brand will do, most of the offered products are
air-cooled, 3600 RPM units, and will be satisfactory for
in-frequent use at minimal expense.

Or if you, like myself, can remember the time last week that
you were in the dark for 4 hours; and the time before that
for 3 hours last month, you need a low RPM unit. A few
smaller units are available that run at 1800 RPM; these are
more suitable for continuous use. A slower running unit will
produce less noise, last longer and be more fuel-efficient.
The purchase price is somewhat higher, however these units
generally offer better voltage regulation, along with a more
conservative current rating. For frequent, long-term use the
1800-RPM units are worth consideration.
              ---------------------------------------

NOTE !!! - Per National Electrical Code Article 702-6,
Installing a hard wired connection from a generator to your
home, business etc. requires a suitable transfer switch as
Tony mentions above.   This serves two purposes: 1) it keeps
the generator from back feeding into the AC input and
possibly electrocuting someone working on the lines!!! and
it also serves 2) to keep your generator from being damaged
once the AC is restored!

73, Ron
      ==================================

REMINDER: Louisa Hamfest, May 4, 2002.

      ===================================
KEN TRAINING DURING MAY AND JUNE WILL FOCUS ON
THE NATIONAL TRAFFIC SYSTEM AND TRAFFIC HANDLING

All of May and the first week of June will be focusing on
lecture type material regarding NTS, Radiograms, Abbreviated
ARRL Numbered Radiograms, Service Messages  etc.

A few weeks in June will be spent with net members actually
receiving and SENDING radiograms for practice!  This will
give everyone a chance to copy and write/send message
traffic.  All VHF and UHF nets are invited to
participate!!!  Here is a chance for Technicians and others
to experience real traffic handling in a no stress
environment.   Study the first 5 weeks of material and then
on KEN, June 10, I'll send out some sample messages over the
net to give everyone a chance to copy a little. (They will
also be sent out over the e-mail lists on the web so others
can use the same material on local nets that week.) On June
17th, I'll be standing by to RECEIVE message traffic from
YOU!  VHF/UHF Nets can take traffic addressed to me or they
can send practice messages among net members on
participating nets.

DON'T PANIC!   No one will laugh.  Everyone can stand some
practice.
We are all here to practice and learn.

JOIN US!