On Thu, 14 Jul 2011 13:00:02 -0700 (PDT), Tom Horne
wrote:

On Jul 13, 3:24*pm, "D.A. Tsenuf" wrote:
Our cabin recently was subjected to multiple days of no electricity during
to a bad storm taking out trees and power lines
I would like to set up a generator to run the following
1) * *well water pump 3/4 hp (120v)
2) * *refrigerator (120v)
3) * *freezer (120v)
4) * *hot water heater (240v)
5) * *stove (240v)

I would like to set it up so that is one appliance is drawing power,
everything else waits.
It would also be nice to set up the chain in the order listed above

It should also be noted that:
a) the stove is optional since there is a great fire pit where food can be
cooked and hot water heated in large enough quantities for hand and
dishwashing and sponge baths.
b) * *the hot water heater is big enough to hold enough water from one
heating cycle for all daily hand and dishwashing needs + couple of showers.
Which means that unless there are more than 2 people using the cabin, it
would only need to run once - possibly in the morning to start the day
c) * *the freezer only needs to run once every 2 days
d) * *the refrigerator only needs to run once a day if access is controlled,
otherwise twice a day will keep it cold enough
e) * *the well water pump only needs to run if water pressure has dropped
low enough to trigger it.

I already have an electric start generator to run everything at the same
time.
But I would prefer not to load it to the gills at the same time,

So I'm looking at
1) * *a box that will make sure that when the generator is going, it will
sequentially feed the 5 devices and then shut off by itself when there is no
demand...
2) * *If the generator is going, then IF a higher priority device wants
power it can bump of a lower priority one. After which the bumped device
gets serviced.

Any help and suggestions are appreciated

Heating anything with resistive electric heat is an offense against
the laws of natures God. Since you didn't mention space heating I'll
assume that it is not electric. That raises the question of what it
is fueled by. If you want to put your home on an electricity diet
then put in an propane fueled hot water heater, a propane fueled
stove. You then have a propane adapter fitted to your generator so
that you no longer have to handle gasoline unless you run out of
propane. That would leave only the well pump, refrigerator, and
freezer to be powered by the generator. You will have reduced the
load on the generator considerably and made the generator much easier
to run.

If you really want to implement a priority sequential operating scheme
then you will need four relays with normally closed auxiliary
contacts. The control voltage for all of the relays comes through
each auxiliary contact in turn. As long as the the relays upstream of

I think you left out some CTs. I would have to see it on paper to be
able to follow your suggestion. If you get bored, I would like to see
a rough sketch of what you come up with. This doesn't seem to be as
"simple" as you suggest, but I could be wrong.

the load in question are open then their auxiliary contact will be
closed and control current will be available to the relays down line
from each relays auxiliary contact. If the water pumps relay is
pulled in then the remaining loads will not have control current and
they will remain off. Once the water pressure reaches cut out then
that relay would relax thus closing it's auxiliary contact and
permitting the refrigerator to run. When both the water pump and the
refrigerator have reached their set points the control power would
reach the freezer's relay allowing the freezer to run until it is cold
enough and control current would then be passed along to the hot water
heater. When the hot water heater reaches it's upper limit then it's
relay would relax thus closing it's auxiliary contact and permitting
the stove to get power. If any higher priority load comes on it opens
the control power circuit to the lower priority loads and they drop
out until control power is again available because the relays for the
higher priority load is now open thus closing it's auxiliary contact
and passing control current along the chain to the lower priority
load. This scheme has the virtue of electrical simplicity but it does
mean that you will have to be careful in what load you are using so as
not to start a higher priority load when what you really want to run
at that moment is a lower priority load. Manually opening and closing
switch rated breakers is a much cheaper and somewhat more flexible way
to accomplish this but if you have to have automatic load selection
then that is the simplest means I know to accomplish that.