nadogail
Well-known member
Thanks for the info, I will have to find an O Scope and check the waveform from my 10KW Chicago Electric Alternator.
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Before you buy a Chinese generator:
- Thread starter Mike007
- Start date
dave*99
Well-known member
I had a good talk with my friend who sells generators. He bought a testing device to check the hertz a unit puts out. They should be 60 hertz, but many of the non sine wave units are all over the place, even top name units. Every sine wave unit is at 60 hertz when tested. The tester is very expensive, over two grand. You can run anything you want on any kind of generator you want, but it will be a slow death to your electronic equipment. The worse the generator the quicker death will occur. I have a Kipor 6000 sine wave and love it. Not only does it have low idle, but it only revs slightly higher with many lights, tv, and others stuff. I go outside and can hear the neibors unit as loud as mine and his is 500 ft away vs thirty ft for mine. My also sips fuel.
If your buddy is in the biz and he bought a "testing device" for his work and spent over 2 grand - it's probably not just a multimeter. Yes, as others have said, many multimeters can read frequency.
But let's recognize that this whole thread is focused on power quality issues. And the tool for measuring power quality is a power quality analyzer. My Fluke 345 cost over 2 grand. It measures frequency.
But it also measures total harmonic distortion.
Distortion factor
Individual harmonic levels.
So after you use a multimeter to confirm voltage = 120V and Frequency = 60 Hz, and your equipment still refuses to run - a power quality analyzer is useful.
The utility company is held to a THD and individual harmonic spec by the public service commission that controls the price they can charge for electricity.
Typically the THD requirement is THD < 5% and Individual harmonic <3%.
You can see these distortions on an oscilloscope - but turning that displayed waveform into a distortion number is not simple.
In summary - if your generator is producing power at the correct voltage, and frequency - AND with low distortion, the equipment will run fine.
Another thing to consider is the load you apply to your generator. Distortion on power waveforms is often caused by the applied load. A simple resistive load like an incandescent light bulb will not introduce distortion. But a high power switching power supply - like a hi power desktop computer would have, generates a lot of distortion on the power line.
The utility company system can absorb a lot of that distortion. Your generator is less able to do so. So depending on what types of loads YOU have and the capacity of YOUR generator - YMMV.
Things can be running fine on the generator at one moment - and it all going to hell when a hi power load or distortion producing load turn on.
And as I said before - the power quality analyzer is the tool to use when troubleshooting some of the more difficult scenarios. That topic can get complicated.
TheEquineFencer
Well-known member
If your buddy is in the biz and he bought a "testing device" for his work and spent over 2 grand - it's probably not just a multimeter. Yes, as others have said, many multimeters can read frequency.
But let's recognize that this whole thread is focused on power quality issues. And the tool for measuring power quality is a power quality analyzer. My Fluke 345 cost over 2 grand. It measures frequency.
But it also measures total harmonic distortion.
Distortion factor
Individual harmonic levels.
So after you use a multimeter to confirm voltage = 120V and Frequency = 60 Hz, and your equipment still refuses to run - a power quality analyzer is useful.
The utility company is held to a THD and individual harmonic spec by the public service commission that controls the price they can charge for electricity.
Typically the THD requirement is THD < 5% and Individual harmonic <3%.
You can see these distortions on an oscilloscope - but turning that displayed waveform into a distortion number is not simple.
In summary - if your generator is producing power at the correct voltage, and frequency - AND with low distortion, the equipment will run fine.
Another thing to consider is the load you apply to your generator. Distortion on power waveforms is often caused by the applied load. A simple resistive load like an incandescent light bulb will not introduce distortion. But a high power switching power supply - like a hi power desktop computer would have, generates a lot of distortion on the power line.
The utility company system can absorb a lot of that distortion. Your generator is less able to do so. So depending on what types of loads YOU have and the capacity of YOUR generator - YMMV.
Things can be running fine on the generator at one moment - and it all going to hell when a hi power load or distortion producing load turn on.
And as I said before - the power quality analyzer is the tool to use when troubleshooting some of the more difficult scenarios. That topic can get complicated.
You obviously have a great understanding of electricity, much better than I. The above post probably is above most "gearheads" level of understanding.
Most people think IMO, if a generator doesn't "trip a breaker" everything is OK. As I tell people, utility power and generator power are not the same, utility always wins. Utility, often known as "shore power", "the grid", has a lot more "push" than a generator. You can "cook" a generator end but never really overload it with enough of the "wrong type" of load. There's three loads If I remember correctly that affect a generator, Resistive, the best type, then Inductive and Capacitive. Then there's Power factor, you can probably explain this better than I. Most all portable generators are rated at 1.0 PF (Power Factor) Most commercial ones are rated at 0.8 PF. This rating comes into play when running motor loads and such.
Which motor is best 2 pole or 4 pole?
A 4-pole motor has about 3.0 ft-lbs of torque per horsepower whereas a 2 pole motor has 1.5 ft-lbs of torque. At 60Hz, a 4-pole motor is about 1800 rpm where a 2-pole motor is 3600 rpm. Thus, the 4-pole motor provides higher-efficiency, higher torque per unit of volume and weight.
TheEquineFencer
Well-known member
After going back to the original post and something wyliesdiesels mentioned about bonding....If you're getting "weird Voltages", try this, take a 120V plug and wire the Ground to the Neutral inside the plug and plug it into the generator, then check you voltages. Some generators are not internally bonded, this is a quick way to bond them.
I had a buddy that burned up some "stuff' inside his horse trailer with a generator that wasn't internally bonded a while back. Warranty didn't cover it as his problem was the generator that fried his trailers inverter system. He called asking how to "Bond" a generator. I talked him through how to do it internally on his, but had him install a plug like I mentioned previously to just test the voltage after "bonding" to start with. It fixed his problems.
I always check generator voltages or anything like this L1-L2 (Line to Line), L1-N L2-N, (Line to Neutral), L1-G L2-G (Line to Ground), N-G ( Neutral-Ground) out of habit.
I had a buddy that burned up some "stuff' inside his horse trailer with a generator that wasn't internally bonded a while back. Warranty didn't cover it as his problem was the generator that fried his trailers inverter system. He called asking how to "Bond" a generator. I talked him through how to do it internally on his, but had him install a plug like I mentioned previously to just test the voltage after "bonding" to start with. It fixed his problems.
I always check generator voltages or anything like this L1-L2 (Line to Line), L1-N L2-N, (Line to Neutral), L1-G L2-G (Line to Ground), N-G ( Neutral-Ground) out of habit.
dave*99
Well-known member
You obviously have a great understanding of electricity, much better than I. The above post probably is above most "gearheads" level of understanding.
Most people think IMO, if a generator doesn't "trip a breaker" everything is OK. As I tell people, utility power and generator power are not the same, utility always wins. Utility, often known as "shore power", "the grid", has a lot more "push" than a generator. You can "cook" a generator end but never really overload it with enough of the "wrong type" of load. There's three loads If I remember correctly that affect a generator, Resistive, the best type, then Inductive and Capacitive. Then there's Power factor, you can probably explain this better than I. Most all portable generators are rated at 1.0 PF (Power Factor) Most commercial ones are rated at 0.8 PF. This rating comes into play when running motor loads and such.
Which motor is best 2 pole or 4 pole?
A 4-pole motor has about 3.0 ft-lbs of torque per horsepower whereas a 2 pole motor has 1.5 ft-lbs of torque. At 60Hz, a 4-pole motor is about 1800 rpm where a 2-pole motor is 3600 rpm. Thus, the 4-pole motor provides higher-efficiency, higher torque per unit of volume and weight.
Lots of good info in your post -
PF is in fact related to inductive and capacitive loads. And leads into the discussion of VAR's which as Volts Amps Reactive. A complex representation of watts. Motors are inductive loads and impact PF.
It's a different impact than non linear loads like switching power supplies. Those introduce distortion.
As you said - the power company can drive these reactive and non linear loads better than a small generator.
As for the gearhead (I'm just a gearhead with degrees) know that many of the devices we use can impact the power quality on a generator.
Larger generators with heavier capacities will provide a stout supply of power and drive the complex loads better. And when issues arise - stop and think about how the different loads you are operating may interact.
Keep in mind guys, this thread is 7+ years old and brought back by a new member.