my opinion on generators

[TheEquineFencer]

Onan makes the best. If you're going to use a generator know what you're working with, you get what you pay for. Know how to test it. You need GOOD quality meters;yes METERS you need an amp clamp meter too, Fluke is the best, it's like a Bridgeport Mill, it's what others are judged by. Get one that reads Hz, (frequency). If the generator says it's a 5000 watt, it's only a 5000 watt if it will run at 5000 watts 60 Hz, test it. If you're doing the testing check the no-load Hz. This is the speed the engine is turning. Then load it to full rated load. Do the math, VOLTS X AMPS = WATTS, WATTS/VOLTS = APMS. Don't assume it's 120V do the math. See if it's at 60Hz. Personally, 59 Hz - 63.5 Hz is the recomminded operating range of a generator. Some have electronic governors some have mechanical. Mechanical governors I set at 63.5 Hz no-load and they usually will pull down to 59.5 Hz loaded. If you understand how they work, you can "tweek" a governor to get it right. Use a resistive load for testing, incandestant lights work great, do the math. Then there's what they call inductive loads, MOTORS. Utility power has a lot more "UMPH" than a small generator, kep that in mind. You can cook a small generator end running motors, they will build heat and never trip a breaker sometimes. Honda, Yanmar, ONAN makedecent portables. I've tested them rightout of the box and most will do nameplate rating. The cheap ones from Lowes/Home Depot will almost never come close. If you just running lights, no frig or anything else, it doesn't really matter about Hz, all you're really running is a heater then when you think about it. I have a brand new "off brand" generator sitting here now a guy bought and he's pissed. It's a 1750KW "el cheapo" and the best we can get out of it is 1200 watts. He thought he could run his water pump or frig with it. When you try to start a frig with it, it stops it dead, faster than if you just switched it off! I bought a 10KW load bank to make my testing easier for myself. You can build one to do testing at 120v or 240v if you understand AC power. Please feel free to add comments, I know there's a few more "real generator guys" in here. If there's any of you in my area, come on over and I'll test yours for free. Corona is good, I have the limes in stock!

 

[rockwithjason]

onan is my fav too. we use kholer and generac at work also but the onan units with the cummins diesel engines are the most trouble free. i despise the natural gas units we have, nothing but trouble.

 

[TheEquineFencer]

Vapor or Liquid/Vapor engines do not respond well to loads. They are very sluggish. They can be hard to start at times too. Usually it's because the engine governor sets the throttle at 100% and tries cranking and you do not have enough vacuum to operate the diaphram like it needs to be.

 

[Ron Lombardo]

I have news for you ... everyone is connecting their home generators to natural gas ... has anyone thought to find out if the Utility Infrastructure gas pressures and pipe sizes can handle the massive load being added to the system.

My advise make sure you have a backup for your Vapor or Liquid Vapor Generator ...

 

[TheEquineFencer]

I have news for you ... everyone is connecting their home generators to natural gas ... has anyone thought to find out if the Utility Infrastructure gas pressures and pipe sizes can handle the massive load being added to the system.

My advise make sure you have a backup for your Vapor or Liquid Vapor Generator ...

LOL, I like Diesel or real gas. I have an ONAN 5000W for my use, it's been "tweeked" and can pull 6000W at 60Hz, but will trip the main breaker if held there. I'm guilty as veryone else with a portable stand-by, I forget to run it and when I need to use it a lot of times I have to clean the carb out if I didn't put some Sta-Bil in it. Most Nat gas generators if you know what you are doing can convert them to a dual fuel type. Onan offers this otion on some I know. It will switch itself if it runs out of Natural gas.

 

[ishiboo]

IMO frequency variation/accuracy is not a big deal as long as the output voltage is clean and it responds to loads well (does not drop voltage too significantly.) Nothing is really frequency-sensitive anymore, motors will run SLIGHTLY slower or faster, but few devices care about the actual frequency. A simple decent-quality DVM for $25 is all the average homeowner needs to measure.

Almost all of the HD/Lowes and even the newest Harbor Freight generators are sufficient for 99% of homeowner needs. The Briggs engines are simple, parts are cheap and they're easily found. They're also quite reliable.

Devices are far, far less caring about voltage regulation/etc. these days. Almost all TVs, computers, etc. use power supplies that can accept a WIDE variety of varying input voltages, and will run on unclean power. Quality matters most about starting/running reliability, and then fixing if something goes wrong IMO.

 

[ishiboo]

I have news for you ... everyone is connecting their home generators to natural gas ... has anyone thought to find out if the Utility Infrastructure gas pressures and pipe sizes can handle the massive load being added to the system.

My advise make sure you have a backup for your Vapor or Liquid Vapor Generator ...

The vast majority of backup generator usage occurs NOT during the home heating season, so there is PLENTY of capacity to spare... basically everyone with a furnace could have a backup generator running basic loads without issue.

I don't think we're close to seeing the natural gas generator usage taxing the distribution system at this point, or even close. That being said, for critical power you definitely should have a backup... it's all a matter of what it's worth to you. Do you spend $700 more for a backup for the backup so that $300 of food does't spoil given the small chance the natural gas goes out? Different story if you have healthcare equipment to run, a finished basement relying on a sump pump, etc.

 

[TheEquineFencer]

IMO frequency variation/accuracy is not a big deal as long as the output voltage is clean and it responds to loads well (does not drop voltage too significantly.) Nothing is really frequency-sensitive anymore, motors will run SLIGHTLY slower or faster, but few devices care about the actual frequency. A simple decent-quality DVM for $25 is all the average homeowner needs to measure.

Almost all of the HD/Lowes and even the newest Harbor Freight generators are sufficient for 99% of homeowner needs. The Briggs engines are simple, parts are cheap and they're easily found. They're also quite reliable.

Devices are far, far less caring about voltage regulation/etc. these days. Almost all TVs, computers, etc. use power supplies that can accept a WIDE variety of varying input voltages, and will run on unclean power. Quality matters most about starting/running reliability, and then fixing if something goes wrong IMO.

LOL. Most computers do have a power supply to filter. Run it on high or low Hz a while, the power supply will quit. Run a motor on low Hz and it gets hot and melts the windings after a while. High Hz will make it run faster. High with a motor is better to a point than low Hz. Microwaves do not like high or low Hz. They just quit. TVs, well there's a good one. My good freind just replaced his, the well pump, home entertainment system and a few other items. They quit over a period of 1 week of running at low Hz and voltage during an extended outage. Yeah, fix it after it breaks? Right, it's better to be informed CORRECTLY before hand. Go to Lowes/Home Depot and buy a new one, if it's not a high end brand like a Honda I will bet It will not do nameplate. I've tested a bunch. The Briggs engines are cheap and reliable, you just have to have the governors set right for the generator to put out right.

 

[ishiboo]

LOL. Most computers do have a power supply to filter. Run it on high or low Hz a while, the power supply will quit. Run a motor on low Hz and it gets hot and melts the windings after a while. High Hz will make it run faster. High with a motor is better to a point than low Hz. Microwaves do not like high or low Hz. They just quit. TVs, well there's a good one. My good freind just replaced his, the well pump, home entertainment system and a few other items. They quit over a period of 1 week of running at low Hz and voltage during an extended outage. Yeah, fix it after it breaks? Right, it's better to be informed CORRECTLY before hand. Go to Lowes/Home Depot and buy a new one, if it's not a high end brand like a Honda I will bet It will not do nameplate. I've tested a bunch. The Briggs engines are cheap and reliable, you just have to have the governors set right for the generator to put out right.

Not at all. ALL computers have a power supply. They also operate on ALL DC voltages, so the simplest power supply could tolerate a huge range, and a modern switching supply will tolerate anything reasonable you'd throw at it. Most computer power supplies are dual rated/UL listed at both european 50 and US 60hz... many are also input-rated between 100 and 260v without even switching them, those wouldn't even care about voltage... though feeding a lot of RF would cause problems.

A TV would not know the difference. Note that this is the hz we are referring to, voltage is a different story. I am not sure about old magnetron microwaves, but an inverter microwave wouldn't care... and my educated guess would be that a magnetron microwave wouldn't care about a +/- 5hz difference either.

This is assuming to reasonable ranges you'd see a generator outputting, as you said they (unless an inverter) are based off RPM, so you shouldn't see less than 55hz or more than 65hz unless something is seriously screwed up. Outside those ranges you will also see voltage regulation problems which are a significant issue for most devices.

 

[TheEquineFencer]

Most of the Lowes/Home Depot generators as RPM/Hz goes down voltage does too.Hz and voltage go hand in hand with the cheaper generators. As voltage goes down, your amp load rises. Keep running things on dirty power and see what happens.

 

[ishiboo]

Most of the Lowes/Home Depot generators as RPM/Hz goes down voltage does too.Hz and voltage go hand in hand with the cheaper generators. As voltage goes down, your amp load rises. Keep running things on dirty power and see what happens.

Definitely a direct correlation on non-inverter generators... that's why a DVM is all you need as I said... as long as the voltage is good to go, you should be fine. Joe Blow does not need a $150 Fluke to see if his generator is going to kill his appliances. The best piece of advice is sizing appropriately for start-up loads.

I think your idea of "as voltage goes down, your amp load rises" is interesting. Kind of. An intelligent power supply like the ones I refer to which are well-adapted to varying input voltages/frequencies/etc. will increase current to provide the same output. However, on a simple load like a light bulb or motor (without a drive), as voltage goes down current will go down as well.

 

[TheEquineFencer]

Definitely a direct correlation on non-inverter generators... that's why a DVM is all you need as I said... as long as the voltage is good to go, you should be fine. Joe Blow does not need a $150 Fluke to see if his generator is going to kill his appliances. The best piece of advice is sizing appropriately for start-up loads.

I think your idea of "as voltage goes down, your amp load rises" is interesting. Kind of. An intelligent power supply like the ones I refer to which are well-adapted to varying input voltages/frequencies/etc. will increase current to provide the same output. However, on a simple load like a light bulb or motor (without a drive), as voltage goes down current will go down as well.

You obviously have not done your homework. Think about this, as voltage drops the amp load rises. That's why if you have weak battery in your car and keep trying to crank it, you will burn up the starter. Low voltage/high amperage. Go get a meter that reads Hz and your voltmeter and run a test and try to prove me wrong running a motor. Set your generator to run at 55Hz and start the motor, check the amp load. Then turn it up to 60Hz and start the same load. Onan higher end generators use a voltage regulator that even as the Hz drops as the generator get's hit with a load, it will hold the voltage at 240V; assuming it's a 240 connected generator, because it's easier for the motor load to recover.

 

[TheEquineFencer]

Not everyone is as smart as you. I'm trying keep the average Joe from cooking his stuff and you're trying to change Ohm's law. If it's running at the correct voltage and Hz, he's OK, you're saying that's not correct.

 

[James-W]

Your starter burns out not because it draws more current due to low battery voltage, it burns out because the battery voltage is so low the starter isn't turning over (or turning very slowly) and the same winding(s) has to handle all the current. In some cases it MAY burn out, or not.

Look, in simple circuits like light bulbs, etc, it is very easy to calculate the current.

If you have 120 volts and you have a light bulb, lets the say the resistance is 20 ohms, then the current flowing will be 6 amps.

If you drop the voltage down to 100 volts, the resistance is still 20 ohms, the current flowing will be 5 amps.

If you drop the voltage down to 80 volts, the resistance is still 20 ohms, the current will be 4 amps.

For circuits like this, as the voltage goes down, the current goes down. Now obviously the light bulb will not be as bright with the lower voltage. If you want the bulb to be the same brightness, then you need to lower the resistance in order to draw more current in order to get the same wattage so that the light bulb will be the same intensity. But as the voltage goes down, if everything else stays the same, the current will go down as well.

 

[ishiboo]

You obviously have not done your homework. Think about this, as voltage drops the amp load rises. That's why if you have weak battery in your car and keep trying to crank it, you will burn up the starter. Low voltage/high amperage. Go get a meter that reads Hz and your voltmeter and run a test and try to prove me wrong running a motor. Set your generator to run at 55Hz and start the motor, check the amp load. Then turn it up to 60Hz and start the same load. Onan higher end generators use a voltage regulator that even as the Hz drops as the generator get's hit with a load, it will hold the voltage at 240V; assuming it's a 240 connected generator, because it's easier for the motor load to recover.

Simply incorrect. As voltage drops the "amp load" goes lower for most simple loads... like a light bulb or motor.

Why are you now comparing hz vs current, when we were discussing voltage vs current? A faster hz will cause the motor to run faster, of course. The point though is the small % of frequency difference in a properly operating generator is not enough to cause a problem, even if it's the 55hz instead of 60.

Not everyone is as smart as you. I'm trying keep the average Joe from cooking his stuff and you're trying to change Ohm's law. If it's running at the correct voltage and Hz, he's OK, you're saying that's not correct.

Let's keep this civil... I am not formally educated, this happens to be just something that interests me so I am sharing my knowledge and opinions as you did... no need to be "smarter" or anything

I am not changing Ohm's Law at all, I think you're misunderstanding it. I = V / R... as voltage goes down, current goes down when all remains the same. Motors, light bulbs, etc. all have a resistance that for the purposes of this discussion remains constant.

I am not saying at all that "If it's running at the correct voltage and Hz, he's OK, you're saying that's not correct"... what I am saying is that if voltage is correct, frequency will be close enough to 60hz that your devices will be fine, and that most Home Depot/Lowes/etc. generators you consider "inferior" are fine with the "sensitive electronics" you seem to indicate they won't be. I'm also saying the end user does NOT need a frequency-counting meter or expensive meter of any kind to know if their generator is okay or "safe" to use.

 

[TheEquineFencer]

Like I said before, go do some testing and try to prove me wrong. A motor trying to start and run on low Hz pulls more amps and runs hotter. It's like trying to start a straight shift car off at just above idle, you put aheck of a strain on something. Trying to pull the same load at below rated will cause your engine in the car to heat more.
Is there something wrong with trying to check and make sure it is right? I mean get real, most folks don't know squat about a generator other than you put gas in it and if it burns a light bulb it must be right? From what you're saying that's pretty much true and it's not.

 

[ishiboo]

Like I said before, go do some testing and try to prove me wrong. A motor trying to start and run on low Hz pulls more amps and runs hotter. It's like trying to start a straight shift car off at just above idle, you put aheck of a strain on something. Trying to pull the same load at below rated will cause your engine in the car to heat more.

That's fine, but that's not ohm's law and again the mathematics we were discussing was VOLTAGE. Yes, a lower frequency will produce a larger current given the same voltage with an AC motor, but it's proportional... so instead of 5.6a your reefer is now taking 6.1a or however the math works out. Big deal.

There are very different dynamics at play, so that's not a particularly useful analogy.

Is there something wrong with trying to check and make sure it is right? I mean get real, most folks don't know squat about a generator other than you put gas in it and if it burns a light bulb it must be right? From what you're saying that's pretty much true and it's not.

That's not what I said at all. I said you do not need a frequency meter and/or Fluke to determine if your generator is okay to use, nor are the Home Depot/Lowes generators insufficient for 99% of peoples needs... both contrary to your original statement.

Do the math, VOLTS X AMPS = WATTS, WATTS/VOLTS = APMS

Just noticed this... I guess it goes along with your Ohm's law understanding

Household electrical systems are AC. Volts * amps does NOT equal watts with AC power, it equals volt-amps.

 

[TheEquineFencer]

That's fine, but that's not ohm's law and again the mathematics we were discussing was VOLTAGE. Yes, a lower frequency will produce a larger current given the same voltage with an AC motor, but it's proportional... so instead of 5.6a your reefer is now taking 6.1a or however the math works out. Big deal.

Well now, let's see. So now you're running the A/C system or you water pump for your well at your house with your portable generator. The pump or A/C motor yopur running is rated to run at 5.6A and now it's running at 6.1A, an AMP load above the name plate rating and you run it for a week or so, guess what, it's building heat and will quit. Yes, it's a big deal. That's like saying you can run a 100A breaker at 90-100 Amps and it's OK. It will trip.
If everything is "right" yes you can do it by the seat of your pants, but if it's not, you'd better know what you're working with.