sine waves are giving me a headache!

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jbmaine

jbmaine

Member
Apr 4, 2009
90
USA
Hi all, I posted a few days ago about getting a UPS to run with my P68 to correct power flickers and for when I use my portable generator ( not a honda) to power my stove during power outages. I got several recommendations for units around the $70-100 range. I was also told my harman needed a pure sine wave. I've done some research and this is what I've found. APC brand has a stepped approximation to a sine wave. Cyberpower brand has a simulated sine wave. Tripplite has sine wave on AC power and pwm sine wave on battery power. I don't know the difference in these different sine waves, if any, and am starting to wonder if I'm making a mountain out of a mole hill. If a UPS doesn't damage a computer how can it damage a pellet stove? Has anyone actually damaged their pellet stove using a UPS? Is there something obvious that I'm missing? Any thoughts or opinions would be greatly appreciated.
Thanks
JB
 
jbmaine said:
Hi all, I posted a few days ago about getting a UPS to run with my P68 to correct power flickers and for when I use my portable generator ( not a honda) to power my stove during power outages. I got several recommendations for units around the $70-100 range. I was also told my harman needed a pure sine wave. I've done some research and this is what I've found. APC brand has a stepped approximation to a sine wave. Cyberpower brand has a simulated sine wave. Tripplite has sine wave on AC power and pwm sine wave on battery power. I don't know the difference in these different sine waves, if any, and am starting to wonder if I'm making a mountain out of a mole hill. If a UPS doesn't damage a computer how can it damage a pellet stove? Has anyone actually damaged their pellet stove using a UPS? Is there something obvious that I'm missing? Any thoughts or opinions would be greatly appreciated.
Thanks
JB
Click to expand...

All yer missin' on the computer / pellet stove comparison is the fact that your computer doesn't have any electric motors. A "modified" or "simulated" or "stepped approximation" is simply turning "on" and "off" all the electric motors (circ fan, comb fan, auger) about 30 times per second. Electronics don't mind. Electrics do. BUT, that's just MY opinion.
 
You got it hoss. Electric motors don't like modified waves. Could possibly heat up/burn out.
 
jbmaine said:
Has anyone actually damaged their pellet stove using a UPS?
Click to expand...

This is a good question imo. I'll be interested in seeing if anyone answers yes to this.
 
Please don't take this the wrong way, but are any of you electrical engineers? I don't know anything about sine waves, UPS, or even electricity for that matter, but I live next the an electrical engineer/Physisist and he runs his stove off a generator when the power goes out. He doesn't use any UPS or converter of any kind. When I mentioned the opinions on this thread he said that he thought it was overkill and that the stoves were a lot "heartier' than people give them credit for. Again, this is not my opinion, just asking if there is anyone with an engineering background on hear that agrees/disagrees.
 
I ran my stove directly off my generator for 11 days straight last winter. No ill effects
 
Flammam said:
I ran my stove directly off my generator for 11 days straight last winter. No ill effects
Click to expand...

I ran my stove for 9 days last winter during the "Great Ice Storm of 2008" and did not notice any problems. I'm wondering if the theory is that the effects are something that happens over time?
 
The generator isn't the issue. They produce an AC sine wave(although spiky). An Invertor mimics a sine. A UPS is using an invertor to create an AC sine out of DC power. There is a difference.
 
hossthehermit said:
jbmaine said:
Hi all, I posted a few days ago about getting a UPS to run with my P68 to correct power flickers and for when I use my portable generator ( not a honda) to power my stove during power outages. I got several recommendations for units around the $70-100 range. I was also told my harman needed a pure sine wave. I've done some research and this is what I've found. APC brand has a stepped approximation to a sine wave. Cyberpower brand has a simulated sine wave. Tripplite has sine wave on AC power and pwm sine wave on battery power. I don't know the difference in these different sine waves, if any, and am starting to wonder if I'm making a mountain out of a mole hill. If a UPS doesn't damage a computer how can it damage a pellet stove? Has anyone actually damaged their pellet stove using a UPS? Is there something obvious that I'm missing? Any thoughts or opinions would be greatly appreciated.
Thanks
JB
Click to expand...

All yer missin' on the computer / pellet stove comparison is the fact that your computer doesn't have any electric motors. A "modified" or "simulated" or "stepped approximation" is simply turning "on" and "off" all the electric motors (circ fan, comb fan, auger) about 30 times per second. Electronics don't mind. Electrics do. BUT, that's just MY opinion.
Click to expand...

Don't computers have electric fans to cool the electronics off? Would an UPS with some kind of modified sine wave damage them also? Or does it make a difference that electric motors in pellet stoves are more heavy duty.
Thanks
JB
 
jtakeman said:
The generator isn't the issue. They produce an AC sine wave(although spiky). An Invertor mimics a sine. A UPS is using an invertor to create an AC sine out of DC power. There is a difference.
Click to expand...

I am now more confused than I was before ;)
 
hossthehermit said:
All yer missin' on the computer / pellet stove comparison is the fact that your computer doesn't have any electric motors.
Click to expand...

Sure they do... fans .... but they are DC coming from the computer's power supply.
 
I did a test on my Harman with a smaller APC UPS which I am sure
is NOT a pure sine wave output.

Results: The AC motors were protesting by making odd noises almost like howling.
I hope no damage was done.
These noises went away after I plugged the stove back into the wall outlet.
I would hope that a Pure Sine Wave UPS would not cause this.


Just my 2 cents!
 
As stated earlier, the motors in a pellet stove all want 60 Hz AC - the closer it is to a sine wave, the happier the motors will be. These motors are all of the induction type (invented by Tesla, don't you know) and feeding them with anything other than a sine causes the smooth build up and decay of magnetic fields in the motor to go haywire. PC power supplies expect very little from their power input - most switching power supplies will run just as happily on DC as they will on a standard AC power source. Because of this, UPS manufacturers are more concerned with battery life and power efficiency than they are with simulating a sine wave. Some UPS just produce a square wave and filter it just enough so that it doesn't produce too much RF noise.

Inverters that produce something close to a sine wave are designed for appliances that may contain an induction motor or an old school linear power supply. These usually don't have the automatic switchover features that a UPS has.
 
NH Pellet Head said:
Dougsey said:
I use the APC Smart UPS 1000.

http://www.apc.com/resource/include/techspec_index.cfm?base_sku=SUA1000
Click to expand...

How long will this run your stove in the even of an outage? I'd love to have a set up that runs the stove for a few hours in the event of a power outage so that we don't get smoke in the house as the stove shuts down. I would normally hook up the generator...unless I'm sleeping.
Click to expand...


Not all that long... maybe an hour. Gives you enough time to either hook up the generator or do a graceful shutdown of the stove.
 
Like Dougsey I use a UPS to keep the pellet burner going until I get the Honda inverter providing power. UPS last about an hour. One nice feature of some UPS is they have an audible alarm which wakes me up when the power goes out overnight. Another nice thing about them is they do a nice job of power conditioning when the winter utility power gets nasty.

My Harman pellet furnace has 3 motors (auger motor, combustion fan motor, and a large duct distribution fan motor) I have not had any of them fail. This UPS has automatically switched in 3 or 4 times in the last couple of years. It will all happen seamlessly and automatically even when the Honda kicks in.
 
Hi -

I'm using an APS 1250 Tripplite with a pair of 1100 AH, AGM battries. The Tripplite has an PWM (pulse width modulated) output.
I have run this setup on my P-68 for 3 years now and have had none of the motor issues that other people have noted.
This may be due to Tripplite having a better output character in regards to the "simulated" sine wave.
This setup has had some serious workouts and I am very satisfied as to its capabilities.
I am a technician and have been around industrial UPS systems for over 20 years.
I think that most of the motor howling issues are related to inferior inverter design of some UPS manufacturers.
Just my two cents.
 
This can get confusing but cowboy billy rus his whlole farm of off a modified wave set up so they can run motors, a freq drive is a pulsed DC wave to adjust the freg to change speed, the ups that you people say that wont run a motor have issues other than a DC mod wave form. Might have something to do with their intended function.
 
j-takeman said:
The generator isn't the issue. They produce an AC sine wave(although spiky). An Invertor mimics a sine. A UPS is using an invertor to create an AC sine out of DC power. There is a difference.
Click to expand...
Why would it be spiky if the flux is broken gradually? As you say the inverter just pulses a sine wave. I'm trying to learn here too as are some others, Randy
 
j-takeman said:
The generator isn't the issue. They produce an AC sine wave(although spiky). An Invertor mimics a sine. A UPS is using an invertor to create an AC sine out of DC power. There is a difference.
Click to expand...

I agree!

Here is a link to a fellow member's web page: http://www.markdfellows.com/untitled1.html
Here is a link he has on that page to a pure sine wave inverter for $156 : http://www.amazon.com/dp/B002O5P8BA...iveASIN=B002O5P8BA&adid=0ESA00FTN0GNPA9MBDWT&

The inverter I tried on my P61 was a cheap B&D from WallyWorld. Like I said earlier, the AC motors did like this inverter!
 
OldScrap said:
As stated earlier, the motors in a pellet stove all want 60 Hz AC - the closer it is to a sine wave, the happier the motors will be. These motors are all of the induction type (invented by Tesla, don't you know) and feeding them with anything other than a sine causes the smooth build up and decay of magnetic fields in the motor to go haywire. PC power supplies expect very little from their power input - most switching power supplies will run just as happily on DC as they will on a standard AC power source. Because of this, UPS manufacturers are more concerned with battery life and power efficiency than they are with simulating a sine wave. Some UPS just produce a square wave and filter it just enough so that it doesn't produce too much RF noise.

Inverters that produce something close to a sine wave are designed for appliances that may contain an induction motor or an old school linear power supply. These usually don't have the automatic switchover features that a UPS has.
Click to expand...
huh?
 
I sometimes wish that my Harman ran DC motors with a "built-in" inverter like the Quads!!
 
jbmaine said:
Hi all, I posted a few days ago about getting a UPS to run with my P68 to correct power flickers and for when I use my portable generator ( not a honda) to power my stove during power outages. I got several recommendations for units around the $70-100 range. I was also told my harman needed a pure sine wave. I've done some research and this is what I've found. APC brand has a stepped approximation to a sine wave. Cyberpower brand has a simulated sine wave. Tripplite has sine wave on AC power and pwm sine wave on battery power. I don't know the difference in these different sine waves, if any, and am starting to wonder if I'm making a mountain out of a mole hill. If a UPS doesn't damage a computer how can it damage a pellet stove? Has anyone actually damaged their pellet stove using a UPS? Is there something obvious that I'm missing? Any thoughts or opinions would be greatly appreciated.
Thanks
JB
Click to expand...

mountain out of a mole hill.
 
I have run mine on my 5000 watt generator last year for several hours with no problems, but then I have the Quad AE with the DC motors. I have just purchased the battery backup system for the stove in case power goes out while we are not home. This is one nice feature of the Quad's.
 
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