Suggestions on generators?

[Eupher]

Minor nitpick......the fastest genset/transfer switch combination takes an absolute minimum of 8 seconds to come on line after an outage (hospital rated units)........the average is around fifteen to twenty seconds.

By the time that the transfer switch senses that an outage has occurred (usually 2 seconds), and the generator engine starts and comes up to proper RPM (usually about 4 seconds at the very best), and the transfer switch "syncs" the voltage and 60 cycle current, you have the eight second minimum.  Anything less and you run the risk of powering your load with lower than necessary voltage (bad), something other than 60 cycle AC (even worse), and unless the governor has stabilized the engine speed, your output in both voltage and frequency will vary all over the map (disastrous).......

doc

I can't argue your technical expertise, doc, but I've seen it happen. Power went out (or seemed to go out) with a flicker, I hear the generator kick on, and lights are on. Couple seconds, tops.

[Chris_]

quote: I can't argue your technical expertise, doc, but I've seen it happen. Power went out (or seemed to go out) with a flicker, I hear the generator kick on, and lights are on. Couple seconds, tops. end quote:

The only way that would be possible is if the mains power was doing strange things before the actual outage occurred, that caused the transfer switch to start the generator in advance of the actual failure (which is possible, depending on the sophistication of your transfer switch)......in that case, when the mains power finally went to zero, all the systen had to do was switch......the generator was already running before the actual outage.

I have seen this happen a few times with the very large commercial gensets that I have worked with, but it is pretty rare.........in these cases the transfer switch logic circuitry monitors the incoming voltage and frequency, and if it drifts outside of preset parameters, the system starts the generator.......in essence preparing itself for an imminent failure......that may be what you have experienced with your system.  I would be surprised at that level of sophistication in a "home" system......

Easy way to find out.......go over to your service panel with a watch, kill the main breaker, and time how long it takes for the genset to take over......downside.....you will have all of your clocks flashing "12:00" until you reset the damn things......

doc

[Eupher]

quote: I can't argue your technical expertise, doc, but I've seen it happen. Power went out (or seemed to go out) with a flicker, I hear the generator kick on, and lights are on. Couple seconds, tops. end quote:

The only way that would be possible is if the mains power was doing strange things before the actual outage occurred, that caused the transfer switch to start the generator in advance of the actual failure (which is possible, depending on the sophistication of your transfer switch)......in that case, when the mains power finally went to zero, all the systen had to do was switch......the generator was already running before the actual outage.

I have seen this happen a few times with the very large commercial gensets that I have worked with, but it is pretty rare.........in these cases the transfer switch logic circuitry monitors the incoming voltage and frequency, and if it drifts outside of preset parameters, the system starts the generator.......in essence preparing itself for an imminent failure......that may be what you have experienced with your system.  I would be surprised at that level of sophistication in a "home" system......

Easy way to find out.......go over to your service panel with a watch, kill the main breaker, and time how long it takes for the genset to take over......downside.....you will have all of your clocks flashing "12:00" until you reset the damn things......

doc

   Again, I understand only about a third of what you've said. It's possible that I didn't really have an outage - just a stumble enough to kick the generator on. It ran a few seconds with the lights on, then stopped. All was well.

I paid some pretty good coin for this Kohler and I'm not disappointed. Granted, it is a home unit but in testing the thing after installation, I had just about every damn electrical light, circuit, and thing going. The only point that the system didn't like was when I turned the second oven on to 500 deg. F. along with everything else including a 3.5 ton A/C unit. The unit complained about that one! 

We have combo above/below ground electrical power and despite some pretty strong winds I've not had a significant outage. But I'll be damned if I go through another one like I had in Salt Lake City. We went six days without power. That one sucked donkey ass. 

[Chris_]

  Again, I understand only about a third of what you've said. It's possible that I didn't really have an outage - just a stumble enough to kick the generator on. It ran a few seconds with the lights on, then stopped. All was well.

I paid some pretty good coin for this Kohler and I'm not disappointed. Granted, it is a home unit but in testing the thing after installation, I had just about every damn electrical light, circuit, and thing going. The only point that the system didn't like was when I turned the second oven on to 500 deg. F. along with everything else including a 3.5 ton A/C unit. The unit complained about that one! 

We have combo above/below ground electrical power and despite some pretty strong winds I've not had a significant outage. But I'll be damned if I go through another one like I had in Salt Lake City. We went six days without power. That one sucked donkey ass. 

The challenges of rural living......I've seen the incoming voltage at our farm in central MO vary from a low of 180 to a high of 275 volts coming from our local coop.......and my mother-in law complains that lightbulbs only last a few months......no wonder.

Something else that I've noticed with generators.......unless you have a very good one, they do not produce a pure "sine wave" output, and some electronics don't appreciate it at all.  In my case, I have our TV, and my rather expensive antique McIntosh stereo equipment, as well as a couple of computers running on UPS's of various sizes, and our house has an alarm system.........when running on generator, the UPS's complain loudly by a beeping alarm, even though they are being supplied with AC power, as well as the alarm panel.........they just don't like the waveform of the AC....

The microwave acts strangely as well on generator, it works OK, but has a different sound......don't know what that is all about either, but as long as it works.

doc

[Eupher]

The challenges of rural living......I've seen the incoming voltage at our farm in central MO vary from a low of 180 to a high of 275 volts coming from our local coop.......and my mother-in law complains that lightbulbs only last a few months......no wonder.

Something else that I've noticed with generators.......unless you have a very good one, they do not produce a pure "sine wave" output, and some electronics don't appreciate it at all.  In my case, I have our TV, and my rather expensive antique McIntosh stereo equipment, as well as a couple of computers running on UPS's of various sizes, and our house has an alarm system.........when running on generator, the UPS's complain loudly by a beeping alarm, even though they are being supplied with AC power, as well as the alarm panel.........they just don't like the waveform of the AC....

The microwave acts strangely as well on generator, it works OK, but has a different sound......don't know what that is all about either, but as long as it works.

doc

In doing my research, the "unclean power" deal that you mentioned seemed to be more of a problem with the Generac -- less so with the Kohler.

Kohler 12RESL

[Chris_]

In doing my research, the "unclean power" deal that you mentioned seemed to be more of a problem with the Generac -- less so with the Kohler.

Kohler 12RESL

Just read the specs, and it does have microprocessor controlled input power monitoring that I was discussing from my experience with commercial units.......looks like a great unit.

I also noticed that they rate their outage response time at 10 seconds......

The THD rating that they discuss is what likely causes my problems with my little Honda, it was not designed to those specs.

doc

[Eupher]

Just read the specs, and it does have microprocessor controlled input power monitoring that I was discussing from my experience with commercial units.......looks like a great unit.

I also noticed that they rate their outage response time at 10 seconds......

The THD rating that they discuss is what likely causes my problems with my little Honda, it was not designed to those specs.

doc

Yes, I saw the 10 second thing as well - which leads me to conclude that maybe all I had was a power blip enough to kick the unit on.   

[NHSparky]

The challenges of rural living......I've seen the incoming voltage at our farm in central MO vary from a low of 180 to a high of 275 volts coming from our local coop.......and my mother-in law complains that lightbulbs only last a few months......no wonder.

Something else that I've noticed with generators.......unless you have a very good one, they do not produce a pure "sine wave" output, and some electronics don't appreciate it at all.  In my case, I have our TV, and my rather expensive antique McIntosh stereo equipment, as well as a couple of computers running on UPS's of various sizes, and our house has an alarm system.........when running on generator, the UPS's complain loudly by a beeping alarm, even though they are being supplied with AC power, as well as the alarm panel.........they just don't like the waveform of the AC....

The microwave acts strangely as well on generator, it works OK, but has a different sound......don't know what that is all about either, but as long as it works.

doc

True dat.  I don't run any sensitive electronics (television, computer) on the generator, even if it's going through a power conditioner.  The THD is just too great.  Just for the hell of it last year when I was sans normal power, I used a Fluke scope on one of the outlets.

NOT pretty.  Hell, even my Fluke 89 showed 10-12 volt surges when the furnace or well pump kicked in.

[Chris_]

True dat.  I don't run any sensitive electronics (television, computer) on the generator, even if it's going through a power conditioner.  The THD is just too great.  Just for the hell of it last year when I was sans normal power, I used a Fluke scope on one of the outlets.

NOT pretty.  Hell, even my Fluke 89 showed 10-12 volt surges when the furnace or well pump kicked in.

If you look at the spec sheet on Eupher's generator, the THD is really low, and the voltage regulation is rated at 1.5% from no load to 100%.......those are really good numbers.

I wish my local utility could match that........hell, last time I complained about voltage variations I was nastily advised that "we are allowed 15%!!!"   WTF is up with that........you would think they would take a bit more pride in their performance.......but they are a monopoly after all........

doc

[Wineslob]

The challenges of rural living......I've seen the incoming voltage at our farm in central MO vary from a low of 180 to a high of 275 volts coming from our local coop.......and my mother-in law complains that lightbulbs only last a few months......no wonder.

Something else that I've noticed with generators.......unless you have a very good one, they do not produce a pure "sine wave" output, and some electronics don't appreciate it at all.  In my case, I have our TV, and my rather expensive antique McIntosh stereo equipment, as well as a couple of computers running on UPS's of various sizes, and our house has an alarm system.........when running on generator, the UPS's complain loudly by a beeping alarm, even though they are being supplied with AC power, as well as the alarm panel.........they just don't like the waveform of the AC....

The microwave acts strangely as well on generator, it works OK, but has a different sound......don't know what that is all about either, but as long as it works.

doc

That stuff is crap. I'll "dispose" of it for you. I mean, who wants tubes? 

[Chris_]

That stuff is crap. I'll "dispose" of it for you. I mean, who wants tubes? 

I have vintage in both tubes and solid state........but there is nothing like tubes to keep you warm on a cold winter evening......

doc

[NHSparky]

If you look at the spec sheet on Eupher's generator, the THD is really low, and the voltage regulation is rated at 1.5% from no load to 100%.......those are really good numbers.

I wish my local utility could match that........hell, last time I complained about voltage variations I was nastily advised that "we are allowed 15%!!!"   WTF is up with that........you would think they would take a bit more pride in their performance.......but they are a monopoly after all........

doc

15 percent?  Really?  Hell, when I worked for SCE they were allowed +/- 5 percent.  But droop isn't what worries me, it's the surge (drop) you get when a really large 240 volt load kicks in.  Even a momentary jump from, say, 15 percent load to over 50 percent load is gonna result in a momentary (hell, even sub-cycle duration) surge that electronics aren't really happy to see.  Also why I have power conditioners on all my big-ticket electronics--and I still lose clocks here from time to time.

Again, I'd call them back and find out.  15 percent sounds way too high to me.  If they mean +/- 7.5 percent, I can believe that, but that's about as much as NEMA and NEC allows.  The below link is from Allegheny Power, but I have a feeling pretty much all utilities are following these standards.  Also your state PUC will have more information.

http://www.alleghenypower.com/PowerQuality/RelatingStandard.asp

NEC, NEMA and standard Allegheny Power regulation limits

It is important to understand that voltage regulation standards are developed for the facility’s service entrance, not necessarily at the point of equipment utilization. To understand the reason why voltages measured at the point of equipment utilization may be out of compliance with voltage regulation standards, but still acceptable for equipment operation, the relationship between the NEC, NEMA MG-1 recommendations and voltage regulation standards must be examined.

The NEC states that to obtain reasonable efficiency of operation, conductors for feeders and branch circuits, as defined in Article 100C, should be sized to prevent voltage drop that does not exceed 5 percent. Therefore, the voltage should not drop more than five percent from the origination of a circuit to its furthest outlet. Voltage drop is defined as a function of the impedance of the conductors in the circuit, along with the type of raceway or enclosures utilized, type of circuit, single- or three-phase, along with the circuit’s power factor.

It is because of the recommended acceptable allowance voltage drop by the NEC that manufacturers design their equipment in accordance with NEMA MG 1, 12.44 that states: Motors shall operate successfully under running conditions at rated load with variation in the voltage up to the following percentages of rated voltage at rated frequency :

[Thor]

That stuff is crap. I'll "dispose" of it for you. I mean, who wants tubes? 

Tubes have a better audio output than solid state. Unless one spend an AWFUL lot of money, the best they're going to get is a good class "B" amplifier from a solid state system. There were some motherboards that were using tubes for their sound cards back a few years ago. The heat can be a problem.

As far as generators, when I was working cable TV, the company spent an awful lot of money on power inverters for their maintenance trucks. They had a pure sine wave output. The generators at the head ends where I worked  also had a good enough output for the electronics. WE also had battery back ups and UPS for the cable telephone system and associated computers. Then again, the standby generators were not cheap. They were of the most expensive and most reliable of them all.

[NHSparky]

Power consumption notwithstanding (which is where you get the heat issue), tubes are damned near indestructible.

[Thor]

Power consumption notwithstanding (which is where you get the heat issue), tubes are damned near indestructible.

I dunno, I've replaced my fair share of tubes in my life. I DO like them better for most electronic things. ( I was replacing tubes from our TV set when I was six)

[Wineslob]

Tubes have a better audio output than solid state. Unless one spend an AWFUL lot of money, the best they're going to get is a good class "B" amplifier from a solid state system. There were some motherboards that were using tubes for their sound cards back a few years ago. The heat can be a problem.

I won't get into the tubes vs solidstate arguement. However, when you have speakers like these:







you can hear the difference. Tubes are just too "soft" sounding to my ears. Yes, those are mine.

On to generators, if someone was so inclined, they could build one:
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=45416