Is there such a device that you can plug into your car and is capable
of turning the car's DC 12V power into household 110V AC ? Please
don't laugh if this is a stupid idea, I am just wondering if the power
generated by the
small alternator on a running car would be enough to drive a force air
furnance during black out ?

My neighbour is buying an expensive Honda generator as a backup power
supply.
Since I can't afford to do the same and black out is not uncommon in
my area,
I am thinking if the alternator on my three cars can do the same trick
and
power at least the furnance during a winter black out ?

Appreciate if you can share your knowledge / experience.

Check your local camping/RV retailer. What your looking for is a power
inverter, but for the power capability your looking for, is probably
going to run you as much, if not more, than your neighbors Honda generator.

JW wrote:

Is there such a device that you can plug into your car and is capable
of turning the car's DC 12V power into household 110V AC ? Please
don't laugh if this is a stupid idea, I am just wondering if the power
generated by the
small alternator on a running car would be enough to drive a force air
furnance during black out ?

My neighbour is buying an expensive Honda generator as a backup power
supply.
Since I can't afford to do the same and black out is not uncommon in
my area,
I am thinking if the alternator on my three cars can do the same trick
and
power at least the furnance during a winter black out ?

Appreciate if you can share your knowledge / experience.

(JW) wrote:
Is there such a device that you can plug into your car and is capable
of turning the car's DC 12V power into household 110V AC ? Please
don't laugh if this is a stupid idea, I am just wondering if the power
generated by the
small alternator on a running car would be enough to drive a force air
furnance during black out ?

My neighbour is buying an expensive Honda generator as a backup power
supply.
Since I can't afford to do the same and black out is not uncommon in
my area,
I am thinking if the alternator on my three cars can do the same trick
and
power at least the furnance during a winter black out ?

Appreciate if you can share your knowledge / experience.

Lessee...a blower motor on a furnace typically runs about 10A @ 120V...that's
1200W continuous. I'll ignore the startup current, but it's probably pretty
gnarly. 1200W inverters are out there (primarily for the RV crowd), but they
ain't cheap. We're talking 100A+ out of the battery, which is quite a draw --
you're not going to get that out of the alternator -- basically you're going to
suck the life out the (non deep cycle) battery in short order. Now, RVers
address this with a bank of deep cycle batteries, but you're getting into the
range of a genset by the time you've bought the batteries and the inverter (it's
quieter, 'tho).

JW wrote:
Is there such a device that you can plug into your car and is capable
of turning the car's DC 12V power into household 110V AC ? Please
don't laugh if this is a stupid idea, I am just wondering if the
power generated by the small alternator on a running car would be
enough to drive a force air furnance during black out ?

My neighbour is buying an expensive Honda generator as a backup power
supply. Since I can't afford to do the same and black out is not
uncommon in my area, I am thinking if the alternator on my three cars
can do the same trick and power at least the furnance during a winter
black out ?

Appreciate if you can share your knowledge / experience.

You can buy little inverters that run off your car battery and generate
110V AC. I bought a 400W inverter for about $50 (then found the same
one at Sam's Club a few months later for $25. D'oh!) The size you need
depends on the power requirement of your furnace blower. The inverter
does not need the car to be running; just the battery charged. You'll
have to run the engine every once in a while to top off the battery.
You might want to buy a deep-cycle battery just for this use.

How are you planning to wire it up?

Bob

Andy Hill wrote:

(JW) wrote:

Is there such a device that you can plug into your car and is capable
of turning the car's DC 12V power into household 110V AC ? Please
don't laugh if this is a stupid idea, I am just wondering if the power
generated by the
small alternator on a running car would be enough to drive a force air
furnance during black out ?

My neighbour is buying an expensive Honda generator as a backup power
supply.
Since I can't afford to do the same and black out is not uncommon in
my area,
I am thinking if the alternator on my three cars can do the same trick
and
power at least the furnance during a winter black out ?

Appreciate if you can share your knowledge / experience.


Lessee...a blower motor on a furnace typically runs about 10A @ 120V...that's
1200W continuous. I'll ignore the startup current, but it's probably pretty
gnarly. 1200W inverters are out there (primarily for the RV crowd), but they
ain't cheap. We're talking 100A+ out of the battery, which is quite a draw --
you're not going to get that out of the alternator -- basically you're going to
suck the life out the (non deep cycle) battery in short order. Now, RVers
address this with a bank of deep cycle batteries, but you're getting into the
range of a genset by the time you've bought the batteries and the inverter (it's
quieter, 'tho).


My furnace has a 8.5A fuse in a fusable disconnect (I don't know why, I
didn't wire it like that) and it doesn't blow during startup...

Bob

According to JW :
Is there such a device that you can plug into your car and is capable
of turning the car's DC 12V power into household 110V AC ? Please
don't laugh if this is a stupid idea, I am just wondering if the power
generated by the
small alternator on a running car would be enough to drive a force air
furnance during black out ?

There are 12V inverters that you can buy quite cheaply to get 120V AC
power[+]. However, above about 400W the price starts to jump _very_ steeply.
Given startup surge and wave conditioning requirements for AC induction
motors, an inverter for your furnace blower will have to be in the 2000W+
range. Those things cost more than a consumer grade (ie: Coleman) 3500W
gasoline generator (but not as much as a good Honda).

Furthermore, at that power level, the vehicle's alternator may not be able
to keep up. 60A is about the limit for ordinary cars, 75A is the usual
"top end". Which is only about 720W. The furnace blower steady-state
is going to use up just about all of it.

There are "special" alternators you can install on your car that
produce 120V AC - making your whole car a gas generator. They're
actually quite inexpensive (years back Northern Hydraulics had them for
around $60), _except_ that mounting them is often going to be a b**ch.

These are able to deliver several thousand watts, _however_, they're
not frequency regulated, and thus would not work for furnace blowers which
need a reasonably well controlled 60Hz AC. They're more intended
for things like electric drills and saws that don't care what frequency
the 120V is at.

Sorry, your cheapest option is a gas generator.

[+] I have a couple smallish inverters, and will be building a 12V emergency
lighting/power system in the house. But I won't be able to run motors like
that, it is not intended to be as "capable" as a gas generator. Just simple,
cheap, keeps the lights burning, we can watch emergency broadcasts on
TV, and recharge the cell phone ;-)
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

Backtrack and think about what you are trying to do. First the Honda
generator costs about four times any others. If you need a generator for
high usage all the time the Honda is the way to go. You can buy a 5-6 kw
generator for around $500. It will do everything you need and probably last
you a lifetime at the small usage you need. I bought a 6kw generator about 8
years ago for about $400 and have used it about a dozen times. I have it set
up so it feeds the whole house during power failures. I had lights, TV, and
hot food during the blackout. It won't run the air conditioner but it did
run several fans. Check the prices at the big box stores and warehouse
stores. You don't need state of the art for the small usage it will
receive....


"JW" wrote in message
m...
Is there such a device that you can plug into your car and is capable
of turning the car's DC 12V power into household 110V AC ? Please
don't laugh if this is a stupid idea, I am just wondering if the power
generated by the
small alternator on a running car would be enough to drive a force air
furnance during black out ?

My neighbour is buying an expensive Honda generator as a backup power
supply.
Since I can't afford to do the same and black out is not uncommon in
my area,
I am thinking if the alternator on my three cars can do the same trick
and
power at least the furnance during a winter black out ?

Appreciate if you can share your knowledge / experience.

My father-in-law used to buy these devices for his employees fleet cars.
They worked in the oil patch, and needed to use drills, etc.

He and I opened one of them one day to see what he was getting for him
money. It was
essentially a switch and a 110 receptacle.

The switch cut the voltage regulator out of the circuit and ran the
alternator on full output.
The frequency was whatever you get out of a three phase circuit running at
frequency x.

Sure they worked. I don't recall him ever having burned out alternators
because of it either. But it darn sure wasnt rocket science. And you are
still limited to the wattage that the alternator can put out.

Last point, if one thinks an alternator doesn't put out much at low RPM, he
should remember the days of the generator. These things were borderline at
best, always seemed to have voltage regulator problems.

There is a company called Auragen that makes this type of thing.
They are at http://www.thepcshopper.com/aurasystems/. While
the units are really nice, they are pretty pricey. I am
currently looking a putting one in a mobile TV truck, about $3K.
As others have said, a cheap gas generator goes a long way in
an emergency.

JW wrote:
Is there such a device that you can plug into your car and is capable
of turning the car's DC 12V power into household 110V AC ? Please
don't laugh if this is a stupid idea, I am just wondering if the power
generated by the
small alternator on a running car would be enough to drive a force air
furnance during black out ?

My neighbour is buying an expensive Honda generator as a backup power
supply.
Since I can't afford to do the same and black out is not uncommon in
my area,
I am thinking if the alternator on my three cars can do the same trick
and
power at least the furnance during a winter black out ?

Appreciate if you can share your knowledge / experience.

In article ,
says...
Is there such a device that you can plug into your car and is capable
of turning the car's DC 12V power into household 110V AC ? Please
don't laugh if this is a stupid idea, I am just wondering if the power
generated by the
small alternator on a running car would be enough to drive a force air
furnance during black out ?

As it is now alternators on cars are becoming more and more taxed at
providing enough power for all the widgets and things on a car.

This is part of the move to the 42V electrical systems in cars. I can
understand that - takes 48V to run your phone why not something like a
car.

My neighbour is buying an expensive Honda generator as a backup power
supply.
Since I can't afford to do the same and black out is not uncommon in
my area,
I am thinking if the alternator on my three cars can do the same trick
and
power at least the furnance during a winter black out ?

Appreciate if you can share your knowledge / experience.

Best way to use your car as a generator is not to. You could buy a basic
generator and then wire up your house to accept it as an input. You'd
probably be looking at about $3000 or so.

Other option is a truck with a PTO hooked to a generator. But even that
isn't cost efficient.

"JW" wrote in message
m...
Is there such a device that you can plug into your car and is capable
of turning the car's DC 12V power into household 110V AC ? Please
don't laugh if this is a stupid idea, I am just wondering if the power
generated by the
small alternator on a running car would be enough to drive a force air
furnance during black out ?

My neighbour is buying an expensive Honda generator as a backup power
supply.
Since I can't afford to do the same and black out is not uncommon in
my area,
I am thinking if the alternator on my three cars can do the same trick
and
power at least the furnance during a winter black out ?

Appreciate if you can share your knowledge / experience.

I have a 2200watt continuous/4000 peak inverter wired (not a plug in) to a
2nd, isolated, battery in my truck. It cost $310.00. I use it for running
a skill saw, miter box etc. It is much easier than starting /stopping a
generator much quieter, and doesn't take up any cargo space.

I don't think it would take the place of a generator for continuous use. My
alternator is a 135 amp upgrade but the inverter can draw over 200amps so it
would never keep up with continuous use. Its output is small compared to
even a cheap genset.

It will be cheaper and better to just use a generator.

On 18 Feb 2004 13:53:31 -0800, (JW) wrote:

Is there such a device that you can plug into your car and is capable
of turning the car's DC 12V power into household 110V AC ?

Inverter. Available through many mail-oder sites and most RV or four
wheeling dealers.

Please
don't laugh if this is a stupid idea, I am just wondering if the power
generated by the
small alternator on a running car would be enough to drive a force air
furnance during black out ?

Unlikely. A space heater maybe.

My neighbour is buying an expensive Honda generator as a backup power
supply.
Since I can't afford to do the same and black out is not uncommon in
my area,
I am thinking if the alternator on my three cars can do the same trick
and
power at least the furnance during a winter black out ?

A generator is under $500, an inverter of any capacity would be close
to as much.

Blankets, firewood and candles, along with a propane heater, stove and
lantern are much cheaper, more versatile and more practical.

Jeff

(JW) wrote in message om...
Is there such a device that you can plug into your car and is capable
of turning the car's DC 12V power into household 110V AC ? Please
don't laugh if this is a stupid idea, I am just wondering if the power
generated by the
small alternator on a running car would be enough to drive a force air
furnance during black out ?

My neighbour is buying an expensive Honda generator as a backup power
supply.
Since I can't afford to do the same and black out is not uncommon in
my area,
I am thinking if the alternator on my three cars can do the same trick
and
power at least the furnance during a winter black out ?

Appreciate if you can share your knowledge / experience.

I used to have an '85 Chevy diesel 4x4 that I setup to run a generator
off the driveshaft. There was a flatbed on it and I mounted the
generator to it. I left the front drivetrain hooked up so it was
still driveable (front wheel drive). The rear driveshaft ran the
generator with a small gearbox between the rear driveshaft and the
chain that drove the generator to disengage it so the generator
wouldn't turn when the truck was being driven. I don't remember the
size of the genereator exactly, it's been a while since I sold it. It
was enough to run the whole house with room to spare (it was big...
weighed probably 800-900 lbs). It was originally a tractor PTO
generator.

You just drive it up to the power service panel, set the emergency
brake, pop the transfer case into 2WD, put the rear gearbox into
gear,plug the generator in, and crank up the rpms. There were a
couple times I had to use it for 2-3 days straight... that 6.2L diesel
never missed a beat.

This obviously isn't what you're trying to do, but I thought it was an
interesting semi-related story :-)

I use a 1000 watt generator to run my central furnace - it works
fine,. I was unsure if it would handle the start-up current, but I
have never experienced a problem.

You do NOT need a 4 or 5 kW generator if all you want is to run the
furnace.

Don' try to jury-rig something to your car - just buy a cheap
end-of-season generator in the 1500 to 2000 watt range and you will be
fine.



John Davies
http://home.comcast.net/~johnedavies/
'96 Lexus LX450
'00 Audi A4 1.8T quattro
Spokane WA USA

"JW" wrote in message
m...
Is there such a device that you can plug into your car and is capable
of turning the car's DC 12V power into household 110V AC ? Please
don't laugh if this is a stupid idea, I am just wondering if the power
generated by the
small alternator on a running car would be enough to drive a force air
furnance during black out ?

My neighbour is buying an expensive Honda generator as a backup power
supply.
Since I can't afford to do the same and black out is not uncommon in
my area,
I am thinking if the alternator on my three cars can do the same trick
and
power at least the furnance during a winter black out ?

Appreciate if you can share your knowledge / experience.


What kind of furnace do you have? Electric? Gas? Oil?

I can tell you now, that if you have a heat pump, or straight electric
resistance heat, you cant.

Personally, I have a 25KW Coleman, with a Ford engine that runs on NG, and
my heat pump hasnt even had to be shut down in the last two outages we
had...
If you are in an area that is prone to blackouts, or simply outages due to
ice, or weather related, then you cant afford to be without one.

Tony P. wrote

Other option is a truck with a PTO hooked to a generator.
But even that isn't cost efficient.

How difficult/expensive would it be convert an old yard tractor
(10hp) into a mobile generator for use in case of blackouts and
where would one find the necessary components?

According to HLS Sorry@nospam:

Sure they worked. I don't recall him ever having burned out alternators
because of it either. But it darn sure wasnt rocket science. And you are
still limited to the wattage that the alternator can put out.

As a FYI, some years ago there was a discussion (on this group I think),
where I had suggested that an "alternator configured as 120V source"
unit was limited to about the same wattage as when configured for 12V
(ie: somewhere in the 500-800W range typically).

An automotive engineer familiar with alternator design chimed in and said
that, on the contrary, these things can put out vastly more power. As in,
a 60A alternator reconfigured to drive 120V could actually deliver 60A
at 120V (7200W at 120V instead of 720W at 12V) under the "right conditions".

That would presuppose you're running it at high RPMs [+], and secondly
that current draw and voltage were exactly in sync (ie: pure resistive
loading). If there was significant out-of-phase current/voltage at
those power levels, the thing would self-destruct in very short order
because the thing isn't big enough to dissipate the inductive heating.

It also supposes that the drive belt can stand up to 10 times as much
loading...

[+] the amount of power that a given size of transformer or generator
can generate is highly dependent on AC frequency. Ie: a PC switching
power supply can supply 500W out of a transformer 1.5" in diameter,
(because the transformer is being driven at anywhere from 20Khz to 50Khz),
whereas an ordinary 60Hz transformer for that wattage often weighs 5 pounds
or more and is bigger than an entire PC supply.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

According to Ed Stasiak :
Tony P. wrote

Other option is a truck with a PTO hooked to a generator.
But even that isn't cost efficient.

How difficult/expensive would it be convert an old yard tractor
(10hp) into a mobile generator for use in case of blackouts and
where would one find the necessary components?

You'd need a speed governor and a generator. I was researching this
some years ago because I thought of doing exactly that.

I found that Northern Hydraulics (now just "Northern") and
Princess Auto (more or less the Canadian equivalent of Northern) were
selling brand new "bare" (motorless) 3500 and 5000W generator units for
somewhere in the neighborhood of $200-$400.

[I've seen Princess selling "surplus" 20Kw motor-less generators for
~$800CDN. Drool drool ;-)]

The problem is finding a speed governor that detects the output
frequency of the generator and can adjust the tractor's throttle to
keep the frequency reasonably and consistently close to 60Hz under
wildly varying load. These are usually custom units built into
motor-generator units ("gensets").

Even Northern, who also sold gensets they assembled themselves (from
the generators and motors they also sold) didn't sell the governors
separately.

While yard tractors usually do have a governor already (my 12HP Cub Cadet
certainly does), I don't think they're anywhere near fast or accurate
enough to reliably use in a generator/tractor combo. The one on my
tractor certainly doesn't seem "quick" enough. This presupposes as well
that you get the speed set right in the first place for the governor to
govern.

If you _did_ manage to find the generator/governor units, then the problem
becomes mounting it on the tractor. I had that all figured out for mine -
it would have involved producing a customized version of the snowblower
mount and adding belt drive to link the generator to the accessory clutch
pulley (3/16" or 1/4" steel and some welding). The generator would have
stuck out in front of the tractor almost between the front wheels. But
very easy to mount/dismount.

[The manual for the tractor did say a rear PTO was available for it just
like the big ones on full size tractors, but the local Case-IH dealership
just laughed at the notion that something like that had ever existed.]
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

Not a stupid question. I've tried it myself, using a 700 watt inverter, and
a marine battery. Figure if I can get two hours or so of furnace time, it
would surely be a lot more comfortable than not.

What I found was that the lead in wires they gave me didn't supply enough
amperage to start the fan motor on the furnace. Reaching in to spin the fan
by hand didn't help.

I keep thinking that someday I've got to wire a second battery onto the 12
volt leads of the inverter, but I havn't done it yet.

Keep the inverter as close to the battery as you can -- make the long
distance run with 110 VAC extension cords.

--

Christopher A. Young
Join Alt-Hvac Moderated
A free, easy to use Yahoo! group



"JW" wrote in message
m...
Is there such a device that you can plug into your car and is capable
of turning the car's DC 12V power into household 110V AC ? Please
don't laugh if this is a stupid idea, I am just wondering if the power
generated by the
small alternator on a running car would be enough to drive a force air
furnance during black out ?

My neighbour is buying an expensive Honda generator as a backup power
supply.
Since I can't afford to do the same and black out is not uncommon in
my area,
I am thinking if the alternator on my three cars can do the same trick
and
power at least the furnance during a winter black out ?

Appreciate if you can share your knowledge / experience.

On 18 Feb 2004 13:53:31 -0800, someone wrote:

Is there such a device that you can plug into your car and is capable
of turning the car's DC 12V power into household 110V AC ?

Yes there is such a thing. My buddy used to use one to run his
circular saw on a job site (intermittant use). I don't think your car
would keep up for long with any continuous draw. You gonna leave the
car running all night long?

You could probably run your refrigerator off it, cool it down and then
shut off the car. But not your heating system all the time.

-v.

In article ,
says...
Tony P. wrote

Other option is a truck with a PTO hooked to a generator.
But even that isn't cost efficient.

How difficult/expensive would it be convert an old yard tractor
(10hp) into a mobile generator for use in case of blackouts and
where would one find the necessary components?


That would probably work. But here is the secret - in any generator the
driving engine is rarely the most expensive part.

I'll bet you could find a power plant/generator pair where the power
plant is shot for cheap.

(JW) wrote:

Is there such a device that you can plug into your car and is capable
of turning the car's DC 12V power into household 110V AC ? Please
don't laugh if this is a stupid idea, I am just wondering if the power
generated by the
small alternator on a running car would be enough to drive a force air
furnance during black out ?

My neighbour is buying an expensive Honda generator as a backup power
supply.
Since I can't afford to do the same and black out is not uncommon in
my area,
I am thinking if the alternator on my three cars can do the same trick
and
power at least the furnance during a winter black out ?

Appreciate if you can share your knowledge / experience.

Getting the generator is the easy part. Getting it connected to your house in a
safe manner can be much harder and potentially more expensive.

Most furnaces are hard-wired to the breaker/fuse panel - there is no cord you
can unplug and plug into the generator. Making a "suicide" adapter with a plug
on each end is not a good way ;-)

=========================

There are also non-electric ways to heat, light and cook.

A 22,000 BTU kerosene heater can heat 800 to 1000 sq ft on 3 to 4 of gallons of
kerosene per day.

The heater is about $120, kerosene is about $1.75/gallon.

A windup/solar am/fm radio (FreePlay) is about $70.

Camp stoves (Coleman) are under $100 and propane cylinders for a week's cooking
might be $10.

================

I'm not an off-grid person, I just happen to be prepared for the most likely
local problems.

I bought a kerosene heater in 1999 used it for the first time in January 2000
(during an ice storm - 36 hours without power is the longest so far).

I also have a older Coleman stove and lantern (left over from camping with the
kids) that use liquid "stove fuel" (basically low octane unleaded gasoline) and
my wife has several (mostly decorative) oil lamps - but they always have a
little fuel in them. Cooking on a liquid fuel stove is something of an art, but
I make great omelets ;-)

Oh yes, the home network and DSL have over an hour of backup from a small UPS.
There's also a car charger for the laptop. I have been known to use the laptop
by the light of an oil lamp ;-)

More about me: http://www.jecarter.com/
VB3/VB6/C/PowerBasic source code: http://www.jecarter.com/programs.html
Freeware for the Palm with NS Basic source code: http://nsb.jecarter.com
Drivers for Pablo graphics tablet and JamCam cameras: http://home.earthlink.net/~mwbt/
johnecarter at@at mindspring dot.dot com. Fix the obvious to reply by email.

It's not a completely silly question but you may conclude that this
isn't the best approach either.

The gadget that converts 12-ish V d.c. into 120V a.c. is called a
"power inverter." Punching that term into your favorite search engine
should yield plenty of websites about them. People use 'em to run
*small* 120V appliances in their car or sailboat or wherever. Doing
this is pretty inefficient, so the inverter sucks a lot of input
current and gets nice and hot.

Small ones (few hundred watts steady-state, a bit more than that peak)
are ubiquitously available for as little as $30, but those are best
thought of as a way to let the kids play video games in the back seat,
or perhaps for you to run handheld power tools at a jobsite.

Bigger ones can provide as much as a few kW steady state, but we're
now talking about prices that start well into three figures and run
into the four-digit range, especially if you want gourmet 120V
comparable to what the power company delivers, rather than "close
enough for government work" stuff.

The big ones also drain a battery in a big hurry, and are really
happier with a jumper-cable-style or (robustly) hardwired connection
than with the cigarette lighter outlet. The usual recommendation is
that you keep your car running while using them and/or employ a
separate, deep-cycle (marine-type) battery.


Your proposed application would need one of the huskier ones -- a
residential furnace often has a surprisingly substantial motor, 3/4 or
even 1 hp; and motors usually aren't too happy with either
undervoltage or trashy waveforms. Some advise allowing as much as 3x
the steady-state current draw at startup, so check the peak as well as
the steady-state specs of the inverter.

You might well decide that either there's a cheaper way to get AC in a
power outage or there's a better emergency way to keep the place
warm...

Cheers,
--Joe

PS. Also, educate yourself on how to properly hook up and use a
generator or other alternative AC source so you don't throw it into
the teeth of an overload... or (eeek!) energize a line that somebody
assumed to be dead. (Yeah, we all know what they say about "assume,"
but accidents happen somehow...)

And somewhere around the time of 02/18/2004 13:53, the world stopped and
listened as JW contributed the following to humanity:

Is there such a device that you can plug into your car and is capable
of turning the car's DC 12V power into household 110V AC ? Please
don't laugh if this is a stupid idea, I am just wondering if the power
generated by the
small alternator on a running car would be enough to drive a force air
furnance during black out ?

My neighbour is buying an expensive Honda generator as a backup power
supply.
Since I can't afford to do the same and black out is not uncommon in
my area,
I am thinking if the alternator on my three cars can do the same trick
and
power at least the furnance during a winter black out ?

Appreciate if you can share your knowledge / experience.

What you have asked is not a stupid question, but alot of people have
thought along the same lines that you have. Yes, and no. It depends on
how much electrical power the furnace needs in order to start and run
the blower. If your alternator/battery can supply the power, then
great. Otherwise, you may want to invest in a real generator.


--
Daniel Rudy

Remove nospam, invalid, and 0123456789 to reply.

(Andy Hill) wrote in
:

Lessee...a blower motor on a furnace typically runs about 10A @
120V...that's 1200W continuous. ...

You'll want to check that again.

--
Bert Hyman | St. Paul, MN |

According to Bert Hyman :
(Andy Hill) wrote in
:

Lessee...a blower motor on a furnace typically runs about 10A @
120V...that's 1200W continuous. ...

You'll want to check that again.

Indeed.

Most of the forced air furnaces I've seen use 1/4 or 1/3HP blower motors,
occasionally 1/2HP.

Even a very poorly efficient 1/2HP shouldn't be more than about 7 or
perhaps 8A. A gas generator should be at least double that to drive
the blower, and an inverter, probably triple.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

Bert Hyman wrote:
(Andy Hill) wrote in
:

Lessee...a blower motor on a furnace typically runs about 10A @
120V...that's 1200W continuous. ...

You'll want to check that again.

Sometimes when one pulls numbers out of one's *ss, they stink a bit. OK,
overstating the case a for a residential furnace. Still strikes me as a
marginal idea, at best.

(Andy Hill) wrote in
:

Bert Hyman wrote:
(Andy Hill) wrote in
m:

Lessee...a blower motor on a furnace typically runs about 10A @
120V...that's 1200W continuous. ...

You'll want to check that again.

Sometimes when one pulls numbers out of one's *ss, they stink a
bit. OK, overstating the case a for a residential furnace. Still
strikes me as a marginal idea, at best.

For a -true emergency, it might be OK. But, an inverter with enough
oomph to handle the motor starting loads would still be a big
purchase. If you're serious about this, spend the bucks and get a
real generator and a real transfer switch.

All this has a certain immediate interest to me since I was awakened
at 4AM today by the shriek of my CO detector as it died from a power
outage. Power's back on now (I called home and the answering machine
picked up), but next time, who knows?

--
Bert Hyman | St. Paul, MN |

Actually, maybe you overstated for newer blowers. However, some
of the older ones can be that high. My old furnace, replaced
about 15 year ago and built in 1970, ran pretty close to 10 amps.

Andy Hill wrote:
Bert Hyman wrote:

(Andy Hill) wrote in
m:


Lessee...a blower motor on a furnace typically runs about 10A @
120V...that's 1200W continuous. ...

You'll want to check that again.


Sometimes when one pulls numbers out of one's *ss, they stink a bit. OK,
overstating the case a for a residential furnace. Still strikes me as a
marginal idea, at best.

I'd guess that the full-load or startup amperage on the motor could be that
high, but I doubt many furnace blowers would take that much current once
they were running..

--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from
Home Page: http://www.roberthancock.com/


"Art Todesco" wrote in message
news:R0tZb.229731$U%5.1465896@attbi_s03...
Actually, maybe you overstated for newer blowers. However, some
of the older ones can be that high. My old furnace, replaced
about 15 year ago and built in 1970, ran pretty close to 10 amps.

Andy Hill wrote:
Bert Hyman wrote:

(Andy Hill) wrote in
m:


Lessee...a blower motor on a furnace typically runs about 10A @
120V...that's 1200W continuous. ...

You'll want to check that again.


Sometimes when one pulls numbers out of one's *ss, they stink a bit.
OK,
overstating the case a for a residential furnace. Still strikes me as
a
marginal idea, at best.

According to Robert Hancock :
I'd guess that the full-load or startup amperage on the motor could be that
high, but I doubt many furnace blowers would take that much current once
they were running..

The usual plate ratings on motors are "worst case full load" (delivering
full rated power under worst case manufacturing tolerance and supply voltage).

An efficiently matched motor and blower will be pulling "full load"
(not necessarily "worst case", but close) amps all the time. This goes
for pumps and compressors too.

Startup surge is 2-3 times that (and not listed on the plate).

In other words, a 10A blower motor _will_ pull close to 10A continuously.
20-30A startup surge.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

On 18 Feb 2004 13:53:31 -0800, (JW) wrote:

Is there such a device that you can plug into your car and is capable
of turning the car's DC 12V power into household 110V AC ? Please
don't laugh if this is a stupid idea, I am just wondering if the power
generated by the small alternator on a running car would be enough to drive a force air
furnance during black out ?

When there was a huge ice storm that knocked out the grid in Quebec
and Ontario a few years back I mused about the same problem, how to
get the furnace running without power and avoid the freeze damage to
my home, any home.

This is a thought experiment. I have a natural gas central heating
system. The thermostat and gas valve system works off a small 24Vac
transformer. The fan motor is 1/2hp 115Vac. Its not too hard to
jury rig a stationary exercise bicycle to turn the furnace blower fan
and get the air circulation going. If I hook up a 12 Vdc car battery
to a small 115Vac inverter thence to the 24V transformer can I get the
furnace going and the house heated in an emergency? Can the furnace
valve system work off 24Vdc (two car batteries)? The power draw on
the battery to run the 24Vac parts is minimal so it shouldn't be
necessary to use the car to recharge the battery often.

KLM wrote:

On 18 Feb 2004 13:53:31 -0800, (JW) wrote:

Is there such a device that you can plug into your car and is capable
of turning the car's DC 12V power into household 110V AC ? Please
don't laugh if this is a stupid idea, I am just wondering if the power
generated by the small alternator on a running car would be enough to drive a force air
furnance during black out ?

When there was a huge ice storm that knocked out the grid in Quebec
and Ontario a few years back I mused about the same problem, how to
get the furnace running without power and avoid the freeze damage to
my home, any home.

This is a thought experiment. I have a natural gas central heating
system. The thermostat and gas valve system works off a small 24Vac
transformer. The fan motor is 1/2hp 115Vac. Its not too hard to
jury rig a stationary exercise bicycle to turn the furnace blower fan
and get the air circulation going. If I hook up a 12 Vdc car battery
to a small 115Vac inverter thence to the 24V transformer can I get the
furnace going and the house heated in an emergency? Can the furnace
valve system work off 24Vdc (two car batteries)? The power draw on
the battery to run the 24Vac parts is minimal so it shouldn't be
necessary to use the car to recharge the battery often.

Consider permanently replacing the blower motor with a 24Vdc
unit and a transformer/rectifier for ordinary use. A sturdy
bank of car batteries can power your heating plant often
enough to keep a house from freezing for several days. A
small inverter (400 watts is less than $40 at Sams Club)
can power the control system.

OTOH it doesn't take a very large generator to run a furnace.
Natural_gas/propane fired is advised.

"Chris Lewis" wrote in message
...
| An efficiently matched motor and blower will be pulling "full load"
| (not necessarily "worst case", but close) amps all the time. This goes
| for pumps and compressors too.
|
| Startup surge is 2-3 times that (and not listed on the plate).
|
| In other words, a 10A blower motor _will_ pull close to 10A continuously.
| 20-30A startup surge.
| --
| Chris Lewis, Una confibula non set est
| It's not just anyone who gets a Starship Cruiser class named after them.

That's interesting. My oil-burner furnace is on a 15 amp circuit breaker. The
largest draw seems to be greatest when the oil pump fires up, not when the
blower starts up. I don't think the typical furnace blower motors are even
close to 10A running.

"James C. Reeves" wrote in message
...

"Chris Lewis" wrote in message
...
| An efficiently matched motor and blower will be pulling "full load"
| (not necessarily "worst case", but close) amps all the time. This goes
| for pumps and compressors too.
|
| Startup surge is 2-3 times that (and not listed on the plate).
|
| In other words, a 10A blower motor _will_ pull close to 10A
continuously.
| 20-30A startup surge.
| --
| Chris Lewis, Una confibula non set est
| It's not just anyone who gets a Starship Cruiser class named after them.

That's interesting. My oil-burner furnace is on a 15 amp circuit breaker.
The
largest draw seems to be greatest when the oil pump fires up, not when the
blower starts up. I don't think the typical furnace blower motors are
even
close to 10A running.

Your oil pump likely has a heavier starting load than the blower. This
depends on the fluid and the type of pump/blower.
Your breaker is designed to handle short term overloads (as are fuses). It
will typically have an inverse time overcurrent characteristic. That is- the
time to trip is inversely proportional to the current (within limits) so
that short term high inrush currents can be handled. Otherwise you would be
plagued with unnecessary trips and never get a motor started unless you
wrapped a string around its shaft and started it as a top. A motor may draw
3-7 times rated current on starting. Look at the full load current listed
on the nameplate rather than the "power" listed. It is more meaningful.
--
Don Kelly

remove the urine to answer

"KLM" wrote in message
...
On 18 Feb 2004 13:53:31 -0800, (JW) wrote:

Is there such a device that you can plug into your car and is capable
of turning the car's DC 12V power into household 110V AC ? Please
don't laugh if this is a stupid idea, I am just wondering if the power
generated by the small alternator on a running car would be enough to
drive a force air
furnance during black out ?

When there was a huge ice storm that knocked out the grid in Quebec
and Ontario a few years back I mused about the same problem, how to
get the furnace running without power and avoid the freeze damage to
my home, any home.

This is a thought experiment. I have a natural gas central heating
system. The thermostat and gas valve system works off a small 24Vac
transformer. The fan motor is 1/2hp 115Vac. Its not too hard to
jury rig a stationary exercise bicycle to turn the furnace blower fan
and get the air circulation going. If I hook up a 12 Vdc car battery
to a small 115Vac inverter thence to the 24V transformer can I get the
furnace going and the house heated in an emergency? Can the furnace
valve system work off 24Vdc (two car batteries)? The power draw on
the battery to run the 24Vac parts is minimal so it shouldn't be
necessary to use the car to recharge the battery often.
---------
The problem will be "how long can you drive the fan effectively" 2 minutes?
5 minutes? What condition are you in? A nominal figure for a human is
(was? ) about 1/7 HP continuous. Estimated air flow less than 10% of normal.
--
Don Kelly

remove the urine to answer

In article , KLM wrote:
On 18 Feb 2004 13:53:31 -0800, (JW) wrote:

Is there such a device that you can plug into your car and is capable
of turning the car's DC 12V power into household 110V AC ? Please
don't laugh if this is a stupid idea, I am just wondering if the power
generated by the small alternator on a running car would be enough to
drive a force air furnance during black out ?

When there was a huge ice storm that knocked out the grid in Quebec
and Ontario a few years back I mused about the same problem, how to
get the furnace running without power and avoid the freeze damage to
my home, any home.

This is a thought experiment. I have a natural gas central heating
system. The thermostat and gas valve system works off a small 24Vac
transformer. The fan motor is 1/2hp 115Vac. Its not too hard to
jury rig a stationary exercise bicycle to turn the furnace blower fan
and get the air circulation going. If I hook up a 12 Vdc car battery
to a small 115Vac inverter thence to the 24V transformer can I get the
furnace going and the house heated in an emergency? Can the furnace
valve system work off 24Vdc (two car batteries)? The power draw on
the battery to run the 24Vac parts is minimal so it shouldn't be
necessary to use the car to recharge the battery often.

The AC output of automotive inverters should be good enough for that.
The usual automotive inverter output is what they call a "modified sine
wave", which is more like a "modified square wave". The RMS value of the
output is 120 VAC or reasonably close. The waveform goes like 3/8 cycle
positive, 1/8 cycle zero, 3/8 cycle negative, 1/8 cycle zero.
The RMS voltage of the 60 Hz (or fundamental frequency) component alone
will be a little short of 120 VAC (or tal RMS voltage), and lamps that use
ballasts may run a little dim. Motors will be not quite full blast and
may give noisier vibrations from the harmonics but will basically work,
and should not have trouble unless they barely work with true sine 60 Hz
full 120 VAC. I imagine a motor will heat up a little more with the
different waveform with "slightly wrong" RMS voltage of fundamental
frequency compinent alone, although this should only be a big deal if the
design or condition of the motor and/or the equipment using it is already
marginal.
DISCLAIMER - NO WARRANTY BY ME, especially for monetary amounts in
excess of fees that I get from you for making this post.

- Don Klipstein )

"Don Kelly" wrote in
news:FMb_b.579043$JQ1.480055@pd7tw1no:



"KLM" wrote in message
...
On 18 Feb 2004 13:53:31 -0800, (JW) wrote:

Is there such a device that you can plug into your car and is
capable of turning the car's DC 12V power into household 110V AC ?
Please don't laugh if this is a stupid idea, I am just wondering if
the power generated by the small alternator on a running car would
be enough to
drive a force air
furnance during black out ?

When there was a huge ice storm that knocked out the grid in Quebec
and Ontario a few years back I mused about the same problem, how to
get the furnace running without power and avoid the freeze damage to
my home, any home.

This is a thought experiment. I have a natural gas central heating
system. The thermostat and gas valve system works off a small 24Vac
transformer. The fan motor is 1/2hp 115Vac. Its not too hard to
jury rig a stationary exercise bicycle to turn the furnace blower fan
and get the air circulation going. If I hook up a 12 Vdc car battery
to a small 115Vac inverter thence to the 24V transformer can I get
the furnace going and the house heated in an emergency? Can the
furnace valve system work off 24Vdc (two car batteries)? The power
draw on the battery to run the 24Vac parts is minimal so it shouldn't
be necessary to use the car to recharge the battery often.
---------
The problem will be "how long can you drive the fan effectively" 2
minutes? 5 minutes? What condition are you in? A nominal figure for a
human is (was? ) about 1/7 HP continuous. Estimated air flow less than
10% of normal. --

And who is going to stay up all night to ride the bicycle periodically to
keep the furnace working?

I suggest a more practical thought experiment would be to power the furnace
blower from the same 115vac inverter that runs the thermostat and gas
valve, keeping the 12vdc battery charged running the car engine.

Oh, and if you're enchanted with pedalling a bicycle to save energy, hook
an alternator to it and charge the battery. And don't forget the body heat
you'll generate pedalling... that'll warm the house too. Or at least it'll
warm you....

Bill Vajk wrote:
OTOH it doesn't take a very large generator to run a furnace.
Natural_gas/propane fired is advised.

Hmmm. That's an interesting idea. Who are the quality names in NG and/or
propane-fired gensets?

In article R0tZb.229731$U%5.1465896@attbi_s03,
Art Todesco wrote:
Actually, maybe you overstated for newer blowers. However, some
of the older ones can be that high. My old furnace, replaced
about 15 year ago and built in 1970, ran pretty close to 10 amps.

My lord! That's what an *air conditioner* takes,
with the compressor running!

(Or am I off by an order of magnitude or something?)

David