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generator problem

C

Cat 22

Jan 1, 1970
0
I have a 5700 watt Mcculloch FG5700AK generator. When its under a
good load its ok,but when the load is light/none the freq jumps way
up. The speed sounds about normal, but the frequency measures 180 HZ
at very light/no loads and under quarter load or so the freq drops
back to close to 60 HZ.Output voltage is ~120vac and it does vary
some depending on load. I discovered this when we had a blackout and
i tried to run my new furnace on the generator, it would show fault
led's if the fridge kicked on (momentary voltage sag). or if nothing
else was running besides the furnace.
I measured the noload freq with a fluke meter t ~180Hz- and at first
i thought i just didnt have a connection to the meter probe, but
under load (the lowest load i tried and still got 60Hz was 700 watts)
it drops back to right about 60Hz
Its a new Coleman CP9C Echelon furnace, my old carrier weathermaker
8000 worked fine on the generator. One big difference is the Coleman
draws very little power.

I had thought abut putting this on the furnace circuit:
"Tripp Lite LC 1800 Line Conditioner / AVR System LC1800"
or maybe this:
"Tripp Lite LCR2400 Line Conditioner - Automatic Voltage Regulation
with Surge Protection"
Would an ordinary Computer 1200VA UPS do?

Any ideas? Why does the freq act like that? Time for new generator?

Thanks
Cat22
 
C

Cat22

Jan 1, 1970
0
This seems to be a standard generator and not one of the inverter types.
There is no way for it to really be putting out 180 Hz. It is determined by
the speed of the generator which should be about 3600 RPM. To get to 180 Hz
it would have to turn 3 times that fast which would be around 10,000 rpm.

It is probably putting out some spikes in the voltage and your frequency
meter is picking that up.

If the generator still powers up most loads that do not have any electronics
in them, the generator is probably OK. If the voltage falls way down under
loads like the water heater or lots of lights or even if you have one a load
such as a portable heater or hair dryer and does not come back up in a
second or so , then you may need to look for a new generator. It may help
to replace teh brushes in it if it has any.
I think you are right, the fluke is reading harmonics or something when
there is little to no load. All my other stuff (2 fridges a freezer some
cfl lights and a microwave) run fine, its just this furnace that seems
sensitive to the generator output.
What do you think about either of the two items i listed above to help
clean the power? Would I be wasting my money?
Thanks
Cat22
 
M

Martin Riddle

Jan 1, 1970
0
Cat22 said:
I think you are right, the fluke is reading harmonics or something
when there is little to no load. All my other stuff (2 fridges a
freezer some cfl lights and a microwave) run fine, its just this
furnace that seems sensitive to the generator output.
What do you think about either of the two items i listed above to help
clean the power? Would I be wasting my money?
Thanks
Cat22

Try a resistive load in parallel with the furnace. Such as a 100w
incandesant bulb.
If you have a Kill-a-watt, see what the Power factor is of the furnace.
The 100w bulb might pose enough of a resistive load to the generator to
make things stable.
I agree with Ralph that the brushes or slip rings may be worn or dirty
causing havoc with the generators exciter circuit. But it could be that
furnace motor has lousy PF. Is it a capacitive start or does it have a
start winding?

Cheers
 
J

Josepi

Jan 1, 1970
0
Some things I observe.
The frequency is probably only a function of spikes (as another poster
stated) scrwwing with the zero crossing detector in the Fluke. Since the
freq. measured is a direct 3rd harmonic I would say that is a definite.
Heavier loads tend to disapate the 3rd harmonics or bury it in bigger
amplitude fundamentals for the meter.

Since you have a mechanical waveform generation, if your frequency varied
you would hear the motor increase in speed by that ratio. I doubt you are
hearing that freq. change.


Are there sepearte feedback sensor inputs for the generator regulator? Not
likely but, If so some other options come to mind.

The UPS may have more harmonics than your genny. Some fo these cheaper units
give off slightly filter squarewaves.

The line filters may help but I am not familiar with those ones usage or
response.

Do you have a scope with memory?


I have a 5700 watt Mcculloch FG5700AK generator. When its under a
good load its ok,but when the load is light/none the freq jumps way
up. The speed sounds about normal, but the frequency measures 180 HZ
at very light/no loads and under quarter load or so the freq drops
back to close to 60 HZ.Output voltage is ~120vac and it does vary
some depending on load. I discovered this when we had a blackout and
i tried to run my new furnace on the generator, it would show fault
led's if the fridge kicked on (momentary voltage sag). or if nothing
else was running besides the furnace.
I measured the noload freq with a fluke meter t ~180Hz- and at first
i thought i just didnt have a connection to the meter probe, but
under load (the lowest load i tried and still got 60Hz was 700 watts)
it drops back to right about 60Hz
Its a new Coleman CP9C Echelon furnace, my old carrier weathermaker
8000 worked fine on the generator. One big difference is the Coleman
draws very little power.

I had thought abut putting this on the furnace circuit:
"Tripp Lite LC 1800 Line Conditioner / AVR System LC1800"
or maybe this:
"Tripp Lite LCR2400 Line Conditioner - Automatic Voltage Regulation
with Surge Protection"
Would an ordinary Computer 1200VA UPS do?

Any ideas? Why does the freq act like that? Time for new generator?

Thanks
Cat22
 
I think you are right, the fluke is reading harmonics or something when
there is little to no load. All my other stuff (2 fridges a freezer some
cfl lights and a microwave) run fine, its just this furnace that seems
sensitive to the generator output.
What do you think about either of the two items i listed above to help
clean the power? Would I be wasting my money?
Thanks
Cat22
a steady load, like lights, to get the total load to 700 should allow
the furnace to run just fine. DON'T let the refrige cut in while the
furnace is running.

Only a dual conversion UPS (full online) big enough to handle the
furnace would do any good.
 
B

Bruce Gordon

Jan 1, 1970
0
Cat22 said:
What do you think about either of the two items i listed above to help
clean the power? Would I be wasting my money?

What you need is to run the power to the furnace thru an Isolation
Transformer, which will knock down the spikes in the power from the
genset. We used to have a whole bunch of SOLA Power Conditioners that
were BIG Heavy Ferro-Resonant Transformers with an LC Tuned Secondary
Winding, to take the Spikes out of our Generated Power for a big Xerox
Copy Machines and other sensitive loads.
 
C

Cat22

Jan 1, 1970
0
Try a resistive load in parallel with the furnace. Such as a 100w
incandesant bulb.
If you have a Kill-a-watt, see what the Power factor is of the furnace.
The 100w bulb might pose enough of a resistive load to the generator to
make things stable.
I agree with Ralph that the brushes or slip rings may be worn or dirty
causing havoc with the generators exciter circuit. But it could be that
furnace motor has lousy PF. Is it a capacitive start or does it have a
start winding?

Cheers
I'll rig it up and see what happens, I have a small electric heater i
can use to load it also i can vary that load down to 750 wats
I do have a kill-a-watt, My feeling now is that its the dip when
something comes on that is causing the furnace to drop out

Cat22
 
C

Cat22

Jan 1, 1970
0
... Can I ask what brand / model of furnace ?
and/or what make of controller in the furnace ?
... just for selfish reasons - I got a new Trane
a couple of years ago that I haven't tested
on my Honda generator yet ...
My old Clare ( ~ 1990 ) was fine on generator power.
.. it had a White-Rogers controller if I remember.
The Trane people said they haven't heard of any issues.
Thanks ; John T.
its a Coleman CP9C060B12 gas furnace.
 
C

Cat22

Jan 1, 1970
0
a steady load, like lights, to get the total load to 700 should allow
the furnace to run just fine. DON'T let the refrige cut in while the
furnace is running.

Only a dual conversion UPS (full online) big enough to handle the
furnace would do any good.
the furnace specs say its 7.0 amps total unit draw
The motors are variable speed, DC i believe.
 
C

Cat22

Jan 1, 1970
0
If the furnace doesn't like the power from the generator, it certainly
won't like the near-square-wave output of a typical UPS.

We had a new high efficiency furnace installed and one of the first
questions I asked the installer was whether it would work from a
generator. He said this specific Amana model would even work from an
inverter if needed.
My installer told me before i bought the furnce that it would run on a
generator, the guy who came to look at what was happening when i called
them said it should run on a generator but he didnt know why it wasnt
Whether they work or not is VERY dependent on the design of the power
supply(s) used in the control circuits of the furnace.

A pure sine wave inverter running from a battery might work; just use
the generator to keep the battery vharged. Or build an alternate
power source with an old lawn equipment engine (mower, edger, etc)
powering a 12 volt alternator to keep the battery charged. How to
pages here: http://theepicenter.com/tow082099.html I'll look into that idea

On the 180Hz reading, I agree that it's something internal to the
generator - worn brushes, dirty commutator or slip rings, marginal
voltage regulator. Get a Kill-A-Watt (less than $20) and see what it
says the frequency is. Mine reads fine on commercial AC and on two
different generators - but a frequency meter gives odd readings on one
of the generators.

If motor-driven appliances run OK, the frequency is close to correct.
They do, everything i throw at it works except this new furnace, the old
1995 carrier weathermaker 8000 had run on it several times
 
C

Cat22

Jan 1, 1970
0
Some things I observe.
The frequency is probably only a function of spikes (as another poster
stated) scrwwing with the zero crossing detector in the Fluke. Since the
freq. measured is a direct 3rd harmonic I would say that is a definite.
Heavier loads tend to disapate the 3rd harmonics or bury it in bigger
amplitude fundamentals for the meter.

Since you have a mechanical waveform generation, if your frequency varied
you would hear the motor increase in speed by that ratio. I doubt you are
hearing that freq. change.


Are there sepearte feedback sensor inputs for the generator regulator? Not
likely but, If so some other options come to mind.
how can i determine if I have that?
 
L

Liquid80

Jan 1, 1970
0
responding to http://fuelzilla.com/homepower/generator-problem-54076-.htm
Liquid80 wrote:
We're you able to figure out the issue with your furnace and generator?

I'm in NJ and was out of power from hurricane sandy for 5 days with a sick
1yr old.
I am looking to get a generator that will work with the same furnace that
you have
so I don't have to go through this again in the future if it ever happens
again. I'm
thinking of making a connection from whatever generator I get directly to
the
circuit breakers in the house with something like an interlock kit
(interlockkit.com) but I want to know that the furnace will run correctly
before I
make the investment.
My furnace is brand new Coleman Echelon 9.c.
I'm looking at either gas or propane generators.

Any advice is greatly appreciated!
 
N

Neon John

Jan 1, 1970
0
responding to http://fuelzilla.com/homepower/generator-problem-54076-.htm
Liquid80 wrote:
We're you able to figure out the issue with your furnace and generator?

I'm in NJ and was out of power from hurricane sandy for 5 days with a sick
1yr old.
I am looking to get a generator that will work with the same furnace that
you have
so I don't have to go through this again in the future if it ever happens
again.

I live way back in the mountains, literally 20 miles from anywhere.
Power outages are a regular occurrence thing here. I messed around
with several "solutions". I built this 10kW generator for summer use
to run my AC.
http://www.neon-john.com/Generator/Generator_home.htm
(bottom of the page.)

I used this generator when I was in the restaurant and concessions
business and used it to power my house in the winter where I heat with
propane and wood.

http://www.neon-john.com/Generator/Quiet_pack_55G/Quiet_home.htm

This is a very quiet generator and will almost start my 2.5 ton
central AC unit but not quite.

Like the other generator, it required me to roll it outside, connect
the cord to the dedicated outlet, then lug the fuel containers. As
I've gotten older, that's gotten harder to do so a year ago I solved
my problem once and for all. I installed this generator

http://www.norwall.com/products/Gen...dPackaged-w{47}200-Amp-Service-Rated-ATS.html

and a 500 gallon propane tank. Norwall seems to have the best prices
every time I look around but do shop a bit.

I have about $4000 in my installation. I installed the generator
myself but had a contractor do the utility tie-in. I could have done
it myself in TN but the local inspector has a rep for harassing DIYers
so I paid the guy a little and got a hassle-free inspection.

This is what I should have done years ago. When the power goes out,
the generator's control system waits 10 seconds to make sure it really
is an outage. It cranks and closes the transfer switch 5 seconds
later. This is especially nice when the power goes off when you're in
the middle of a wellpump-fed shower!

Our longest outage since I installed this system was 4 days after a
tornado. Middle of summer, hot and humid. My AC worked just fine so
I was cool, comfortable and clean (electric well pump, remember).

At the light load my house normally presents, my unit uses between 1/4
and 1/2 gallon of propane an hour. That's around 1000 hours or 41
days of capacity, assuming no refill. I keep the tank full.

I do not recommend natural gas. First, it makes less power than
propane. Second, during mass disasters such as just happened, the
natural gas supply frequently goes down because the pumping stations
are taken out. Plus the little bit of survivalist in me wants total
control over my fuel source.

If you don't like the looks of a propane tank, have a direct burial
one installed. Then only a little dome sticks up out of the ground.

Something else you might consider. I moved my vital loads
(refrigerators and lights and wood stove fan) to a sub-panel and power
that panel from a 5kW UPS that I scrounged from a data center. I also
scrounged enough batteries (they change them out on a schedule, not
when they go bad) to power my "vital bus" for 48 hours. Before I
installed the Guardian, that carried me for a day or so without having
to get the generator out.

With the Guardian, when I don't need AC, I only run it about half the
time. The rest of the time I run on UPS. That way I can sleep at
night without the generator noise and still have everything I need
except hot water and the well pump. I have a large enough tank on the
well pump to last a day as long as I don't flush the toilet or try to
take a shower.

Living back in the hills like I do, I've learned to incorporate
redundancy into everything vital. I still have the diesel generator
if the Guardian fails. I have the UPS. I primarily heat with wood
but I have a little propane heater hanging on the wall for in case I
run short of wood or just don't feel like lugging it in. My stove's
electric but I have a propane powered Coleman stove in the closet so I
can cook when the generator is not running.

My advice is don't mess around with jerry rigs and do it right.
Install a propane powered automatic generator. I like my Generac but
the Kohlers are nice too. Do NOT get a Coleman. They are LOUD. My
neighbor bought one based on price. That lasted one power outage. He
replaced it with a Guardian.

One last thing. Mount the generator above the flood plane. On the
coast of NC where they put cabins up on 20 ft stilts, I've seen
standby generators on cantilevered platforms off the side of the
cabin.

The propane tank has to stay on the ground and flooding won't hurt it
but it does have to be strapped down (use mobile home anchors) or it
will float away!

John
John DeArmond
http://www.neon-john.com
http://www.fluxeon.com
Tellico Plains, Occupied TN
See website for email address
 
V

Vaughn

Jan 1, 1970
0
I do not recommend natural gas. First, it makes less power than
propane. Second, during mass disasters such as just happened, the
natural gas supply frequently goes down because the pumping stations
are taken out. Plus the little bit of survivalist in me wants total
control over my fuel source.


Good thoughts, but natural gas sure is convenient if your gas system
survives your particular natural disaster. The last four hurricanes
here haven't caused a bobble in our NG service. After each hurricane, I
have had all the fuel I wanted without standing in one damn line!

So what happens if the natural gas system goes out? Well I'm a bit of a
survivalist also! That's why I have four 100# propane tanks and a
little trailer to take them for refilling should it ever become
necessary. Turn off the NG valve, turn on the propane valve, and make
one quarter-turn mixture adjustment and I am back in business!

Still, I envy Neon John's buried tank.

Whatever you decide, think about your fuel supply and know how much fuel
your generator takes per hour. Then do the math! Figure both the cost
of running your generator through a long outage and how long you can run
with available fuel. Then either have a realistic plan regarding where
your fuel will come from after a disaster, or have a sufficient supply
stored away. Propane has the advantage that it never goes bad. Diesel
stores longer than gas, but it still can have issues.

Vaughn
 
B

Bruce Gordon

Jan 1, 1970
0
My Brother, "The Engineer" is rebuilding his home in a mid-sized city in
Utah. He installed a 1K USG Propane Tank, underground in his yard, and
has NG piped into the house. He also has a 55 USG Drum of 80/87 Aviation
Fuel, sitting on steel stilts, and bolted to the floor and Garage Wall.
All this is to support his Generac 20Kw TriFuel Genset that lives in the
SECURE Generator Room, under part of the Double Garage ground level
Floor. Primary Fuel will be the NG Feed from the local NG Pipeline.
Should that fail then he can switch, the Genset, the Kitchen Stove, the
house H&AC, Hot Water Heater, and the Cloths Dryer, over to the Propane
Tank. The 80/87 AvGas is for the vehicles, and if in dire straights, can
feed the Genset. The Genset can run the WHOLE House, or can be used to
charge an Outback 3648 Inverter with 2500 AmpHours of Battery that also
can run the whole House. The Inverter, Charge Controllers, & Batteries,
live in a Separate Electrical Room next to the Generator Room, under
another section of the Garage Floor. He has twin Outback MX-80 Charge
Controllers, that ties his 6Kw of Roof Mounted Solar Panels, to the
Battery Bank. Barring a Nuclear Air Strike in his valley, he is setup
for just about any eventuality. Just Say'en..... YMMV....
 
D

David Lesher

Jan 1, 1970
0
Vaughn said:
Good thoughts, but natural gas sure is convenient if your gas system
survives your particular natural disaster. The last four hurricanes
here haven't caused a bobble in our NG service. After each hurricane, I
have had all the fuel I wanted without standing in one damn line!

Your gas utility goes to to GREAT lengths to keep the gas from
failing. If it does, it's an enormous economic hit to them.

I recall ~50 years ago the utility lost gas pressure to a
part of a suburb. They had to go to each house, shut off the
gas at the meter, then restart the gas in that neighborhood
and bleed. Then go to each house again, open, and light every
appliance. Repeat in neighborhood after neighborhood.
It took days.

When PG&E blew up San Bruno, parallel pipelines kept the
Peninsula and San Francisco going; in NTSB testimony PG&E said
restarting the city alone would have taken three+ months.

When max usage draws heavily on a system, the utility can add some
higher-Therm propane to the mix.

While gas transmission pipelines do have compressors, often they
are cannibals, burning some of the gas they ship. In any case,
the utility has local storage.

As I recall, much of NYC lacks natural gas distribution, but in
places where disasters have hit, the gas is often the utility that
keeps going.
 
D

danny burstein

Jan 1, 1970
0
In said:
Your gas utility goes to to GREAT lengths to keep the gas from
failing. If it does, it's an enormous economic hit to them.
I recall ~50 years ago the utility lost gas pressure to a
part of a suburb. They had to go to each house, shut off the
gas at the meter, then restart the gas in that neighborhood
and bleed. Then go to each house again, open, and light every
appliance. Repeat in neighborhood after neighborhood.
It took days.

Youngster. Ptfui. How's about when they switched over
from (so-called) "Town Gas" to natural gas. Same problem.
Had to shut down everyone and then reconfigure all
those burners...

Or... when the parts of the US that were transferred
and merged into the sixty cycle electric grid...
As I recall, much of NYC lacks natural gas distribution, but in
places where disasters have hit, the gas is often the utility that
keeps going.

Only a small portion of NYC is natural gas deprived. There
are areas next to the ocean where buildings were badly
damamged enough that the utility shut off all fuel
to the neighborhood.

There are similar, and more widespread, issues where
lots of NJ and Long Island just Isn't There anymore.

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