Running off of generators or inverters

Matthaus wrote:I have moved previously posted information from the Econo Blower Problem Thread that I felt would be helpful in fully exploring this topic, if I have missed anything or messed up I'm sure my fellow forum members will be kind enough to point it out.

Thanks.

Great move! It is amazing how complex this topic is. There are many REASONABLE ASSUMPTIONS folks make that are not true in reality. When a device doesn't work right, it's too easy to focus on the malfunctioning device and not look at the complete system and find the real reason the device is malfunctioning.

Very true, especially if your heated about the situation. Happens to me all the time.

SMITTY wrote:Very true, especially if your heated about the situation. Happens to me all the time.

Youuuuuuuuuuu Smitty................. Never woulda guessed.


i think anyone working on cars somehow looses it quickly!!!!!!!!!!!!!!!!!!!!!!!!!111


Some days it don't take much to set me off....... I'm just sayin'



Rick

Not to get this further off topic but........ that explains why Flyer5 is the way he is (owned his own repair shop for 8 years)!

Matthaus wrote: that explains why Flyer5 is the way he is (owned his own repair shop for 8 years)!

Matthaus wrote:Not to get this further off topic but........ that explains why Flyer5 is the way he is (owned his own repair shop for 8 years)!

WHO, ME ? Now please stay on topic Matt!!

So, has there been any guidance on the use of an inverter generator with our stoves. For one reason or another some people will want to run an inverter. So far I have heard don't use,oversize,has run fine. For me anyway this was the whole point of posting was to make people with inverters aware that they may have problems. Something concrete would be helpful like a DO NOT USE from LL,or "a 5000 watt inverter is needed" or some other solid info. If this has been given somewhere I apologize for missing it. Personally I'm going regular generator for my stove but for some a inverter might be needed or just preferred because of noise,fuel usage,etc....

Hi cmperry. There are many variables that cannot be controlled with regards to back up power, we don't see any possible way to print a statement in the manual that covers all possibilities. I have not seen any other appliances that give such information, if anyone has seen that in an appliance manual I would be interested to read it. I can tell you that the the Coal-trol has no been tested or certified to work with inverters and that comes from the folks at Automation Correct. That is the reason a posted "don't expect trouble free operation when running an inverter", I'm not positive whether it will work or not,so it will require a trial run to see if it will work for each particular case.

My recommendation which I posted stated a while back is: Test your stove with the particular backup power source you have in mind before you actually are in an emergency situation. As Flyer5 posted our stoves are designed as an alternate heating source only, not designed or supported as primary heating source, this is stated clearly in the manual http://www.leisurelinestoves.com/files/34986645.pdf . Therefore make sure you have an primary system that is backed up and tested, ready to go in addition to any backup you install for the stove.

Have you tested your generator with your stove? Please make sure you do.

cmperry wrote:So, has there been any guidance on the use of an inverter generator with our stoves. For one reason or another some people will want to run an inverter. So far I have heard don't use,oversize,has run fine. For me anyway this was the whole point of posting was to make people with inverters aware that they may have problems. Something concrete would be helpful like a DO NOT USE from LL,or "a 5000 watt inverter is needed" or some other solid info. If this has been given somewhere I apologize for missing it. Personally I'm going regular generator for my stove but for some a inverter might be needed or just preferred because of noise,fuel usage,etc....

I don't think that is a rational request, inverter generators are changing every year and the better ones improving every year or so. Some degrade as they are cost reduced WITHOUT model number changes! How can any manufacturer test every inverter generator and track every design change to them?

The generator manufacturers don't publish data that helps at all regarding switching or out of phase motors ( slipping). Generator manufactures can't spec for every possible usage any more than LL can certify every random generator.

The main issue is a "Watt" means little for any application other than resistive loads. Look at any UPS or computer power supply have a wattage and a much higher VA spec. For resistive loads, Voltage multiplied by Amperage (VA) equals Watts. The devices I mentioned need to be wired for the higher VA current rating since the current is VA divided by the applied voltage. Heck, a low loss inductor or capacitor might only use a few watts yet trip a 20A circuit breaker. Not a practical application but true.

For pure inductive or capacitive loads, the above math determines the peak current. But these devices do not have sine wave current waveform. They draw higher peak currents that VA math would suggest. Variable speed motors also draw more peak current than simple math would predict.

Eventually pure better sine wave inverters will probably handle any load a good conventional generator will and likely narrow the dramatic price premium they now command.

For now, the only guidance can be "try an oversized pure sine wave unit from a place you can return it to or grossly oversize".

Matthaus wrote:As Flyer5 posted our stoves are designed as an alternate heating source only, not designed or supported as primary heating source, this is stated clearly in the manual http://www.leisurelinestoves.com/files/34986645.pdf . Therefore make sure you have an primary system that is backed up and tested, ready to go in addition to any backup you install for the stove.

Wait for the fun that breaks out as folks replace their old reliable gas furnaces with a new microprocessor controlled high efficiency, variable output, direct hot surface ignition and flame rectification safety detection. (To squeeze a few more percent efficiency, this is the way gas furnaces are going)

Feed them dirty power and the diagnostic LEDS will light up like a Christmas tree and the furnace will lock out.

They will make the Coal-trol issue when supplied with corrupt power seem darned trivial!

One really needs a 24/7/365 emergency service contract for these new gas furnaces. The igniters fail in 1-3 years even with clean power and are NOT a warranty part. (silicon carbide 1-2 years, silicon nitride 3 or so years) Then add an internet monitor to text your cell phone so you can see if the house has ANY heat when away for a couple days if the igniter fails while away..

Electronics are taking over almost all appliances. Well wired, well sized, clean power generators is becoming a MUST for backups!

About the only reliable unattended back up heat is gas space heaters with standing pilots. Some (at least unvented units) are still allowed standing pilots. They are extremely safe (carbon monoxide), well proven for 40+ years in Europe.

gerry

For those wondering if generator power is a problem and unique to Coal-trol, take a look at a common consumer/small business computer UPS FAQ.

http://www.cyberpowersystems.com/support/faqs/general-ups-faqs.html

"
Can I use my UPS in conjunction with a generator?

CyberPower UPS systems are not designed to work with generators. Many generators output a ‘dirty’ AC signal that is not recognized by the UPS, which causes it to remain functioning off battery power.
"

Really all that means is there are plenty of generators out there that are pretty bad or poorly maintained.

A good conventional generator with brushes and slip rings in good condition as well as brushless generators DO produce clean AC. Also, some inverter sine wave generators have sufficient surge capacity to keep the AC "clean".

I came across this article that explains the "Power Factor" in simple

understandable manner which is what you deal with when using a

generator to supply your house.The first article was written in 1996.

http://www.splatco.com/tips/pwrfact/pfarticl.htm

http://www.sciencedaily.com/releases/20 ... 102304.htm


Hope this helps to explain the reactive power that feeds back into

the power supply when an inductive load is placed on any generator.



BigBarney

BigBarney wrote:I came across this article that explains the "Power Factor" in simple

understandable manner which is what you deal with when using a

generator to supply your house.The first article was written in 1996.

http://www.splatco.com/tips/pwrfact/pfarticl.htm

http://www.sciencedaily.com/releases/20 ... 102304.htm

BigBarney

Those are good power factor primers however the issue is far more complex. They address linear inductive or capacitive loads. Switching loads (electronic speed control) induce energy surges and a reduced speed motor doesn't even have a load at the same frequency as the supply! Thus power factor. The first article does mention a very simple non linear load briefly but nothing regarding off frequency loads.

Finally, they assume a fairly stiff supply. Many generators (principally inverter units) don't have the energy reserve to maintain a sine wave output with switched, non-linear or off frequency loads.

This is a very complicated problem, not easily solved, because of the constantly

switching of different inductive loads.The generator has to able to absorb

the back feed created by the loads, which inverter type generators are not able

to do unless well over sized.The non linear loads are even more of a problem

especially when cycled frequently where more controls are needed but very

expensive to implement.

I posted this to help members to understand the basics of power factor.


BigBarney

BigBarney wrote:This is a very complicated problem, not easily solved, because of the constantly
switching of different inductive loads.The generator has to able to absorb
[clip]
I posted this to help members to understand the basics of power factor.
BigBarney

You made a great point. The real world is so complex one needs a good electrical engineering knowledge AND specific knowledge of the specific equipment.

AC generators ( a heavy rotor generates power, stator is the field) and AC alternators (a light rotor is the field, heavy power generating windings are on the stator) have the mechanical energy of the rotating rotor, engine and flywheel to cope with surges and back feed. Higher end ones (still far cheaper than inverter units) have voltage regulation by controlling the field, just as an automotive alternation does.

Inverter generators generally have very light rotating components particularly when running slow under light load (alternators with little mechanical energy storage) and often no back feed ability other than shunting the back feed to ground (if well designed). They often don't even have a capacitor bank to supply surges. Their alternators are often multi-phase (as in autos) always have power output since at least one phase is always outputting. There are peaks and valleys but always acceptable output to SUPPLY a load. The switching circuits have no mechanism to back feed energy to the rotating components.

At the present, KISS always wins re clean power. (Keep It Simple Stupid) If brushes may be compromised, the complexity of brushless adds value.