Genset voltage reg: capacitor vs. AVR

On Feb 17, 9:57*am, Robert > wrote:
> On Feb 17, 8:49 am, "Existential Angst" > wrote:
>
>
>
>
>
> > "Pete S" > wrote in message
>
> ...
>
> > >I don't understand your question.
> > > If you mean "capacitors" when you say "caps", I don't *know how they would
> > > deal with output voltage regulation in any meaningful way.
>
> > Ditto. *ergo my Q. *I guess they must in some fashion, just like you balance
> > rpc's with caps.
>
> > > What kind, model and serial number *of genset do you have that currently
> > > has no voltage regulation built in to it?
>
> >http://www.generatorsales.com/order/...Generator.asp?...
> > modified for tri-fuel.
>
> > It is regulated, just not to 1 or 2%, a swing of 230 to 250 V, from 50+ amps
> > down to zero amps.
> > If you at mid-load it's 240 V, *that's +/-10V, which is not terrible, but
> > it's not 1% either.
>
> > Assume no electrical-type regulation at all. *There is something between the
> > generator itself and the gas engine that ups fuel flow with load,
> > maintaining a semi-constant voltage. *An AVR sharpens this up.
>
> > I don't quite understand how this works, and part of the intent of Q was to
> > shed some light on this.
>
> > I also figgered that if the feedback between generator and engine was good
> > enough, AVR wouldn't be needed.
> > So basically I"m curious about the design of these things.
> > --
> > EA
>
> > > Pete Stanaitis
> > > ----------------
>
> I thought that it was a possibly that you had heard
> of a "capacitor regulator' that I haven't, after 35
> years as an electronics design engineer. *So I
> googled the subject and was unable to come up
> with a single circuit/instance where a capacitive
> system was used as a regulator....
>
> I have the background to comment on the subject,
> so if you will provide a website that *comments
> on how a capacitor or "capacitive circuit" can
> regulate the output of a genset, I will study it
> and give you an opinion, which, obviously you can
> accept *or reject....
>
> *I don't post this to insult you, but I really don't
> see what you are asking ..- Hide quoted text -
>
> - Show quoted text -

It's not hard to find discussion of caps as voltage
regulators. Here's an example, about a third of the
way down in this thread:

http://www.smokstak.com/forum/showthread.php?t=16338

Seems like a pretty crappy thing to find though on a
$3000 generator.

"Existential Angst" > wrote in message
...
>
> Part of my Q was a suspicion that an AVR proly regulates voltage
> more tightly, but perhaps at the expense of raw current flow. Iow,
> I might get "better" juice, just less of it. Just wondering.....
> --
> EA

For lower power demands a high-end APC SmartUPS can regulate the AC
output if the line goes high or low. I got one free with bad, swollen
batteries. It works without them, or with external batteries plugged
into the rear connector.
http://www.apcmedia.com/salestools/A...8L9X_R0_EN.pdf

> wrote in message
...
On Feb 17, 9:57 am, Robert > wrote:
> On Feb 17, 8:49 am, "Existential Angst" > wrote:
>
>
>
>
>
> > "Pete S" > wrote in message
>
> ...
>
> > >I don't understand your question.
> > > If you mean "capacitors" when you say "caps", I don't know how they
> > > would
> > > deal with output voltage regulation in any meaningful way.
>
> > Ditto. ergo my Q. I guess they must in some fashion, just like you
> > balance
> > rpc's with caps.
>
> > > What kind, model and serial number of genset do you have that
> > > currently
> > > has no voltage regulation built in to it?
>
> >http://www.generatorsales.com/order/...Generator.asp?...
> > modified for tri-fuel.
>
> > It is regulated, just not to 1 or 2%, a swing of 230 to 250 V, from 50+
> > amps
> > down to zero amps.
> > If you at mid-load it's 240 V, that's +/-10V, which is not terrible, but
> > it's not 1% either.
>
> > Assume no electrical-type regulation at all. There is something between
> > the
> > generator itself and the gas engine that ups fuel flow with load,
> > maintaining a semi-constant voltage. An AVR sharpens this up.
>
> > I don't quite understand how this works, and part of the intent of Q was
> > to
> > shed some light on this.
>
> > I also figgered that if the feedback between generator and engine was
> > good
> > enough, AVR wouldn't be needed.
> > So basically I"m curious about the design of these things.
> > --
> > EA
>
> > > Pete Stanaitis
> > > ----------------
>
> I thought that it was a possibly that you had heard
> of a "capacitor regulator' that I haven't, after 35
> years as an electronics design engineer. So I
> googled the subject and was unable to come up
> with a single circuit/instance where a capacitive
> system was used as a regulator....
>
> I have the background to comment on the subject,
> so if you will provide a website that comments
> on how a capacitor or "capacitive circuit" can
> regulate the output of a genset, I will study it
> and give you an opinion, which, obviously you can
> accept or reject....
>
> I don't post this to insult you, but I really don't
> see what you are asking ..- Hide quoted text -
>
> - Show quoted text -

It's not hard to find discussion of caps as voltage
regulators. Here's an example, about a third of the
way down in this thread:

http://www.smokstak.com/forum/showthread.php?t=16338

Seems like a pretty crappy thing to find though on a
$3000 generator.
==================================================

Inneresting thread. But I think one can conclude that caps are not
regulating, they are tuning, balancing. with mebbe an itty bitty bit of
regulation as a perk to tuning.

But if you follow the op Jim McIntyre, what his cap(s) did was raise/lower
the voltage. The unit itself, apparently pretty high quality, seems to have
had inherently good regulation between the generator itself and the motor.
Anthony W. commented that

"It sounds as if Kubota did their homework on the winding ratios in your
set. As you found, the cap value isn't too critical in a "good" set within a
reasonable range. Problems usually only show up when a certain critical cap
value is exceeded.
Also in the case of a non-linear load such as a switching power supply,(if
you run your computer off of one) plug an incandesent lamp or two in as
well. I don't know that it would hurt anything, but the waveform looks
"slanted" on a 'scope when only a switching-type load is applied.
The only troubles I have had with the several old Cap regulated sets I have
owned are bearing issues and the cap going "open". "

And the quality of the linkage between the generator/engine was proly
superior.

Notice, tho, that when McIntyre increased his cap size, the voltage
regulation went from about 1% to 2%.
Note that in mine, a much larger unit, the regulation, from midpoint, is 4%
right now -- not terrible terrible, but again, not 1%.
--
EA

On Feb 17, 9:49*am, "Existential Angst" > wrote:
> "Pete S" > wrote in message
>
> ...
>
> >I don't understand your question.
> > If you mean "capacitors" when you say "caps", I don't *know how they would
> > deal with output voltage regulation in any meaningful way.
>
> Ditto. *ergo my Q. *I guess they must in some fashion, just like you balance
> rpc's with caps.
>
> > What kind, model and serial number *of genset do you have that currently
> > has no voltage regulation built in to it?
>
> http://www.generatorsales.com/order/...Generator.asp?...
> modified for tri-fuel.
>
> It is regulated, just not to 1 or 2%, a swing of 230 to 250 V, from 50+ amps
> down to zero amps.
> If you at mid-load it's 240 V, *that's +/-10V, which is not terrible, but
> it's not 1% either.
>
> Assume no electrical-type regulation at all. *There is something between the
> generator itself and the gas engine that ups fuel flow with load,
> maintaining a semi-constant voltage.

That would be the mechanical engine governor.


An AVR sharpens this up.

Yes


>
> I don't quite understand how this works, and part of the intent of Q was to
> shed some light on this.

See my other post to a discussion.


>
> I also figgered that if the feedback between generator and engine was good
> enough, AVR wouldn't be needed.
> So basically I"m curious about the design of these things.
> --
> EA
>


Do you realize what you got for $2800? They take a Honda
engine and bolt it on to some generator made by someone
else. Perhaps you can shed light on to who that someone
else is, but given that it uses a cap for voltage regulation,
I would not be surprised that it's a cheap Chinese one.
Then they take pretty pictures of the thing with Honda showing
all over in the pretty pics and a lot of people make the
assumption that they are buying a Honda generator.
I don't believe that is the case.

Further arousing suspicion is that they claim it's 15KW.
Then if you read the specs, it says it's rated at 13.5KW
continuous. Then they say it has a 50 amp main
breaker, which equates to 12KW, in my world.

You with me so far? Further arrousing suspicion, they
quote fuel consumption in gallons, ie it's based on running
the engine on gas. So, next, let's look at the spec for
a Honda GX690. It says it produces 22hp running gasoline.
I'm no expert in conversions from gasoline to nat gas, but
AFAIK, when you run a gasoline engine on nat gas, you
have about 15% less energy output. Maybe someone has
the exact number. That means you really have about an
18hp engine.

I've looked into generators a bit and what it takes to
power them. I don't think you can get 15KW out of an
18hp engine. A Generac 12KW unit for example, uses
a 26hp engine.

Just some more things to think about.

On 02/17/2013 06:57 AM, Robert wrote:
> On Feb 17, 8:49 am, "Existential Angst" > wrote:
>> "Pete S" > wrote in message
>>
>> ...
>>
>>> I don't understand your question.
>>> If you mean "capacitors" when you say "caps", I don't know how they would
>>> deal with output voltage regulation in any meaningful way.
>>
>> Ditto. ergo my Q. I guess they must in some fashion, just like you balance
>> rpc's with caps.
>>
>>> What kind, model and serial number of genset do you have that currently
>>> has no voltage regulation built in to it?
>>
>> http://www.generatorsales.com/order/...Generator.asp?...
>> modified for tri-fuel.
>>
>> It is regulated, just not to 1 or 2%, a swing of 230 to 250 V, from 50+ amps
>> down to zero amps.
>> If you at mid-load it's 240 V, that's +/-10V, which is not terrible, but
>> it's not 1% either.
>>
>> Assume no electrical-type regulation at all. There is something between the
>> generator itself and the gas engine that ups fuel flow with load,
>> maintaining a semi-constant voltage. An AVR sharpens this up.
>>
>> I don't quite understand how this works, and part of the intent of Q was to
>> shed some light on this.
>>
>> I also figgered that if the feedback between generator and engine was good
>> enough, AVR wouldn't be needed.
>> So basically I"m curious about the design of these things.
>> --
>> EA
>>
>>> Pete Stanaitis
>>> ----------------
>
> I thought that it was a possibly that you had heard
> of a "capacitor regulator' that I haven't, after 35
> years as an electronics design engineer. So I
> googled the subject and was unable to come up
> with a single circuit/instance where a capacitive
> system was used as a regulator....

it's possible they're being used for power factor correction rather than
regulation. pfc gets to be important with some reactive loads.


>
> I have the background to comment on the subject,
> so if you will provide a website that comments
> on how a capacitor or "capacitive circuit" can
> regulate the output of a genset, I will study it
> and give you an opinion, which, obviously you can
> accept or reject....
>
> I don't post this to insult you, but I really don't
> see what you are asking ..
>


--
fact check required

> wrote in message
...
On Feb 17, 9:49 am, "Existential Angst" > wrote:
> "Pete S" > wrote in message
>
> ...
>
> >I don't understand your question.
> > If you mean "capacitors" when you say "caps", I don't know how they
> > would
> > deal with output voltage regulation in any meaningful way.
>
> Ditto. ergo my Q. I guess they must in some fashion, just like you balance
> rpc's with caps.
>
> > What kind, model and serial number of genset do you have that currently
> > has no voltage regulation built in to it?
>
> http://www.generatorsales.com/order/...Generator.asp?...
> modified for tri-fuel.
>
> It is regulated, just not to 1 or 2%, a swing of 230 to 250 V, from 50+
> amps
> down to zero amps.
> If you at mid-load it's 240 V, that's +/-10V, which is not terrible, but
> it's not 1% either.
>
> Assume no electrical-type regulation at all. There is something between
> the
> generator itself and the gas engine that ups fuel flow with load,
> maintaining a semi-constant voltage.

That would be the mechanical engine governor.
================================================== ==

I sure would like to know the details on how those work.





An AVR sharpens this up.

Yes


>
> I don't quite understand how this works, and part of the intent of Q was
> to
> shed some light on this.

See my other post to a discussion.


>
> I also figgered that if the feedback between generator and engine was good
> enough, AVR wouldn't be needed.
> So basically I"m curious about the design of these things.
> --
> EA
>


Do you realize what you got for $2800? They take a Honda
engine and bolt it on to some generator made by someone
else. Perhaps you can shed light on to who that someone
else is, but given that it uses a cap for voltage regulation,
I would not be surprised that it's a cheap Chinese one.
Then they take pretty pictures of the thing with Honda showing
all over in the pretty pics and a lot of people make the
assumption that they are buying a Honda generator.
I don't believe that is the case.
================================================== ===

McCaulte (sp?) makes the generator.

And yes, they mix'n'match.... but presumably they do it pretty well, altho
I got a li'l short-shrifted on the AVR deal....
I don't know that they are being misleading, as much as emphasizing the
Honda part.... LOL
Thin line, admittedly.






Further arousing suspicion is that they claim it's 15KW.
Then if you read the specs, it says it's rated at 13.5KW
continuous.
=============================================

This is typical. Generac does this.


Then they say it has a 50 amp main
breaker, which equates to 12KW, in my world.
======================================

Yeah, I noticed that. And they trip fast, too!
I may put in my own 50 A slower-tripping or even 60 A breakers.


You with me so far? Further arrousing suspicion, they
quote fuel consumption in gallons, ie it's based on running
the engine on gas. So, next, let's look at the spec for
a Honda GX690. It says it produces 22hp running gasoline.
I'm no expert in conversions from gasoline to nat gas, but
AFAIK, when you run a gasoline engine on nat gas, you
have about 15% less energy output. Maybe someone has
the exact number. That means you really have about an
18hp engine.
===============================================

Again, par for the course. I simply went for the most watts. Those watts
will be similarly de-rated in most scenarios, so I just went with the
biggest number.




I've looked into generators a bit and what it takes to
power them. I don't think you can get 15KW out of an
18hp engine. A Generac 12KW unit for example, uses
a 26hp engine.
================================================

Oh, but I did get very nearly the full 13.5 continuous (on gasoline), and
proly could have gotten sig. more. I'll have to jump/replace the breaker,
tho. Already at near-full load, it started a 26 gal compressor, w/ nary a
hiccup.

A 26 hp engine for 12 kW is suspect as well, from two povs:
First, I suspect Generac hp is like Sears hp.
Second, if it IS 26 hp, yer just sipping lots more gas.... which was one of
the things I was going to discuss in my upcoming Generator Manifesto.....
big-azz generators, in no-load conditions, are not economical.

I really couldn't find much better overall bang fer the buck, watt-wise.
The Honda motor is a plus, and the unit is VERY compact.
Generacs are big and complicated. OK, I spose, for the home-moaner who
justs likes to dial the telephone when sumpn goes wrong, and from what I've
read about generac, they will be using their telephone fairly often.

Here's some of my take on this:

I would recommend the Sam's club 8,750 W blackmax, at $999, for most people
with more than the basic needs. You can get it modified for tri-fuel, and
the link I provided sells a modified blackmax for $1600 -- about a $200-$400
preimum over what you would pay if you did it yourself, but with a lot less
headache, and somewhat of a guarantee. The blackmax also has AVR, iirc, and
performed quite well, before it grew feet.

My unit does not come with a gas tank, but which is actually an advantage,
imo, because you just drop the genset's hose down any gas can (or your car's
gas tank, if you can snake it in), and Wala, gasoline power.

I went for the 15 kW unit, in the second go-around, for many of the reasons
you stated:
By the time you get done de-rating for whatever whatever reasons, you
have a lot less than when you started, so I figgered I'd just double the
size from the gitgo.

Really a lot of g-d work. The other bottom line to all this is that unless
you have a water-cooled 4 cylinder unit, you gotta simply build a separate
sound-proofed shed for these noise buckets.
A lot of my work so far went in to testing, given my cnc liabilities. So
far so good, but really a pita -- for sumpn I may NEVER use.
--
EA


Just some more things to think about.

On Feb 17, 11:23*am, "Existential Angst" > wrote:
> > wrote in message
>
> ...
> On Feb 17, 9:49 am, "Existential Angst" > wrote:
>
>
>
>
>
> > "Pete S" > wrote in message
>
> ...
>
> > >I don't understand your question.
> > > If you mean "capacitors" when you say "caps", I don't know how they
> > > would
> > > deal with output voltage regulation in any meaningful way.
>
> > Ditto. ergo my Q. I guess they must in some fashion, just like you balance
> > rpc's with caps.
>
> > > What kind, model and serial number of genset do you have that currently
> > > has no voltage regulation built in to it?
>
> >http://www.generatorsales.com/order/...Generator.asp?...
> > modified for tri-fuel.
>
> > It is regulated, just not to 1 or 2%, a swing of 230 to 250 V, from 50+
> > amps
> > down to zero amps.
> > If you at mid-load it's 240 V, that's +/-10V, which is not terrible, but
> > it's not 1% either.
>
> > Assume no electrical-type regulation at all. There is something between
> > the
> > generator itself and the gas engine that ups fuel flow with load,
> > maintaining a semi-constant voltage.
>
> That would be the mechanical engine governor.
> ================================================== ==
>
> I sure would like to know the details on how those work.
>

Find the parts diagram for the Honda engine. They typically
rely on centrifugal force. If the engine starts to slow down, the
drop in centrifugal force causes movement of linkage connected
to the carb throttle.




> An AVR sharpens this up.
>
> Yes
>
>
>
> > I don't quite understand how this works, and part of the intent of Q was
> > to
> > shed some light on this.
>
> See my other post to a discussion.
>
>
>
> > I also figgered that if the feedback between generator and engine was good
> > enough, AVR wouldn't be needed.
> > So basically I"m curious about the design of these things.
> > --
> > EA
>
> Do you realize what you got for $2800? *They take a Honda
> engine and bolt it on to some generator made by someone
> else. *Perhaps you can shed light on to who that someone
> else is, but given that it uses a cap for voltage regulation,
> I would not be surprised that it's a cheap Chinese one.
> Then they take pretty pictures of the thing with Honda showing
> all over in the pretty pics and a lot of people make the
> assumption that they are buying a Honda generator.
> I don't believe that is the case.
> ================================================== ===
>
> McCaulte (sp?) makes the generator.

Meccalte. They are an Italian company. You can
buy one of their 12-15KW generator heads for about $800.
Not sure what kind of voltage regulation you get for that price.
Find the model, look up the spec sheet. I'll bet it says you
need 25hp or so to get full power out of it. And I doubt an
engine rated at 22hp on gasoline is capable of that running
on natural gas. Have you tried running it at full load on natural
gas?




>
> And yes, they mix'n'match.... *but presumably they do it pretty well, altho
> I got a li'l short-shrifted on the AVR deal....

There isn't much to it. The engines and generators have
common mounting standards that just bolt together.



>
> Oh, but I did get very nearly the full 13.5 continuous (on gasoline), and
> proly could have gotten sig. more. I'll have to jump/replace the breaker,
> tho. *Already at near-full load, it started a 26 gal compressor, w/ nary a
> hiccup.
>
> A 26 hp engine for 12 kW is suspect as well, from two povs:
> First, I suspect Generac hp is like Sears hp.

It's not Generac specific. Take a look at what Meccalte or other
generator head manufacturers spec for power required to support
12KW, 15KW, etc.





> Second, if it IS 26 hp, yer just sipping lots more gas.... *which was one of
> the things I was going to discuss in my upcoming Generator Manifesto.....
> big-azz generators, in no-load conditions, are not economical.

You can't have it both ways. Well,, actually you can, if you're
willing
to pay for it. You can buy an inverter based generator. That
completely
decouples the rotational speed from the frequency. That way, the
engine can run at low RPMs with low loads. It makes them very
fuel efficient at lower loads and also quiet. But you'll pay $4,000
for maybe 3000 watts.



>
> I really couldn't find much better overall bang fer the buck, watt-wise.
> The Honda motor is a plus, and the unit is VERY compact.
> Generacs are big and complicated. *OK, I spose, for the home-moaner who
> justs likes to dial the telephone when sumpn goes wrong, and from what I've
> read about generac, they will be using their telephone fairly often.

With a 5 to 7KW generator you can easily run a big house.
Except for central AC and electric hot water. On a cheapo
5KW generator we ran 4 refigerator/freezers, two gas
furnaces, 2 gas power vented water heaters, plus some
lights. That was for two large houses.

But if you need to run a machine shop, then it's a whole
different ball game.





>
> Here's some of my take on this:
>
> I would recommend the Sam's club 8,750 W blackmax, at $999, for most people
> with more than the basic needs. *You can get it modified for tri-fuel, and
> the link I provided sells a modified blackmax for $1600 -- about a $200-$400
> preimum over what you would pay if you did it yourself, but with a lot less
> headache, and somewhat of a guarantee. *The blackmax also has AVR, iirc, and
> performed quite well, before it grew feet.

You can get a Briggs and Stratton for the same price. It's probably
made in China, but at least B&S knows about engines, knows about
QC, has a long track record and you know where to find them. Who
is Blackmax? Probably a sticker and label on a China generic.



>
> My unit does not come with a gas tank, but which is actually an advantage,
> imo, because you just drop the genset's hose down any gas can (or your car's
> gas tank, if you can snake it in), and Wala, gasoline power.
>
> I went for the 15 kW unit, in the second go-around, for many of the reasons
> you stated:
> * * By the time you get done de-rating for whatever whatever reasons, you
> have a lot less than when you started, so I figgered I'd just double the
> size from the gitgo.
>
> Really a lot of g-d work. *The other bottom line to all this is that unless
> you have a water-cooled 4 cylinder unit, you gotta simply build a separate
> sound-proofed shed for these noise buckets.
> A lot of my work so far went in to testing, given my cnc liabilities. *So
> far so good, but really a pita -- for sumpn I may NEVER use.
> --
> EA
>
> Just some more things to think about.- Hide quoted text -
>
> - Show quoted text -

On Feb 17, 8:23*am, "Existential Angst" > wrote:
> > wrote in message
>
> ...
> On Feb 17, 9:49 am, "Existential Angst" > wrote:
>
>
>
>
>
>
>
>
>
> > "Pete S" > wrote in message
>
> ...
>
> > >I don't understand your question.
> > > If you mean "capacitors" when you say "caps", I don't know how they
> > > would
> > > deal with output voltage regulation in any meaningful way.
>
> > Ditto. ergo my Q. I guess they must in some fashion, just like you balance
> > rpc's with caps.
>
> > > What kind, model and serial number of genset do you have that currently
> > > has no voltage regulation built in to it?
>
> >http://www.generatorsales.com/order/...Generator.asp?...
> > modified for tri-fuel.
>
> > It is regulated, just not to 1 or 2%, a swing of 230 to 250 V, from 50+
> > amps
> > down to zero amps.
> > If you at mid-load it's 240 V, that's +/-10V, which is not terrible, but
> > it's not 1% either.
>
> > Assume no electrical-type regulation at all. There is something between
> > the
> > generator itself and the gas engine that ups fuel flow with load,
> > maintaining a semi-constant voltage.
>
> That would be the mechanical engine governor.
> ================================================== ==
>
> I sure would like to know the details on how those work.
>
> An AVR sharpens this up.
>
> Yes
>
>
>
> > I don't quite understand how this works, and part of the intent of Q was
> > to
> > shed some light on this.
>
> See my other post to a discussion.
>
>
>
> > I also figgered that if the feedback between generator and engine was good
> > enough, AVR wouldn't be needed.
> > So basically I"m curious about the design of these things.
> > --
> > EA
>
> Do you realize what you got for $2800? *They take a Honda
> engine and bolt it on to some generator made by someone
> else. *Perhaps you can shed light on to who that someone
> else is, but given that it uses a cap for voltage regulation,
> I would not be surprised that it's a cheap Chinese one.
> Then they take pretty pictures of the thing with Honda showing
> all over in the pretty pics and a lot of people make the
> assumption that they are buying a Honda generator.
> I don't believe that is the case.
> ================================================== ===
>
> McCaulte (sp?) makes the generator.
>
> And yes, they mix'n'match.... *but presumably they do it pretty well, altho
> I got a li'l short-shrifted on the AVR deal....
> I don't know that they are being misleading, as much as emphasizing the
> Honda part.... *LOL
> Thin line, admittedly.
>
> Further arousing suspicion is that they claim it's 15KW.
> Then if you read the specs, it says it's rated at 13.5KW
> continuous.
> =============================================
>
> This is typical. *Generac does this.
>
> *Then they say it has a 50 amp main
> breaker, which equates to 12KW, in my world.
> ======================================
>
> Yeah, I noticed that. *And they trip fast, too!
> I may put in my own 50 A slower-tripping or even 60 A breakers.
>
> You with me so far? * Further arrousing suspicion, they
> quote fuel consumption in gallons, ie it's based on running
> the engine on gas. *So, next, let's look at the spec for
> a Honda GX690. *It says it produces 22hp running gasoline.
> I'm no expert in conversions from gasoline to nat gas, but
> AFAIK, when you run a gasoline engine on nat gas, you
> have about 15% less energy output. *Maybe someone has
> the exact number. *That means you really have about an
> 18hp engine.
> ===============================================
>
> Again, par for the course. *I simply went for the most watts. *Those watts
> will be similarly de-rated in most scenarios, so I just went with the
> biggest number.
>
> I've looked into generators a bit and what it takes to
> power them. *I don't think you can get 15KW out of an
> 18hp engine. *A Generac 12KW unit for example, uses
> a 26hp engine.
> ================================================
>
> Oh, but I did get very nearly the full 13.5 continuous (on gasoline), and
> proly could have gotten sig. more. I'll have to jump/replace the breaker,
> tho. *Already at near-full load, it started a 26 gal compressor, w/ nary a
> hiccup.
>
> A 26 hp engine for 12 kW is suspect as well, from two povs:
> First, I suspect Generac hp is like Sears hp.
> Second, if it IS 26 hp, yer just sipping lots more gas.... *which was one of
> the things I was going to discuss in my upcoming Generator Manifesto.....
> big-azz generators, in no-load conditions, are not economical.
>
> I really couldn't find much better overall bang fer the buck, watt-wise.
> The Honda motor is a plus, and the unit is VERY compact.
> Generacs are big and complicated. *OK, I spose, for the home-moaner who
> justs likes to dial the telephone when sumpn goes wrong, and from what I've
> read about generac, they will be using their telephone fairly often.
>
> Here's some of my take on this:
>
> I would recommend the Sam's club 8,750 W blackmax, at $999, for most people
> with more than the basic needs. *You can get it modified for tri-fuel, and
> the link I provided sells a modified blackmax for $1600 -- about a $200-$400
> preimum over what you would pay if you did it yourself, but with a lot less
> headache, and somewhat of a guarantee. *The blackmax also has AVR, iirc, and
> performed quite well, before it grew feet.
>
> My unit does not come with a gas tank, but which is actually an advantage,
> imo, because you just drop the genset's hose down any gas can (or your car's
> gas tank, if you can snake it in), and Wala, gasoline power.
>
> I went for the 15 kW unit, in the second go-around, for many of the reasons
> you stated:
> * * By the time you get done de-rating for whatever whatever reasons, you
> have a lot less than when you started, so I figgered I'd just double the
> size from the gitgo.
>
> Really a lot of g-d work. *The other bottom line to all this is that unless
> you have a water-cooled 4 cylinder unit, you gotta simply build a separate
> sound-proofed shed for these noise buckets.
> A lot of my work so far went in to testing, given my cnc liabilities. *So
> far so good, but really a pita -- for sumpn I may NEVER use.
> --
> EA
>
> Just some more things to think about.

It seems it's often impossible to buy the right package for what
someone wants.

An example is an air compressor. I don't intend to run my air
compressor day in and day out so I don't have the need for a very
heavy duty dual stage air compressor pump like this one:

http://www.northerntool.com/shop/too...ct_42535_42535

I'd like this air compressor pump because it's got an 18 CFM rating at
90 PSI and it's got a decent price.

http://www.northerntool.com/shop/too...7235_200387235

I'd like this motor:

http://www.northerntool.com/shop/too...6765_200306765

When I try an find a reasonably priced horizontal air tank I'm ****ed.
Prices are insane. Looks like my only choice will be to buy a used
horizontal air tank.

On 2/17/2013 9:09 AM, Scott Dorsey wrote:
> > wrote:
>>
>> I think he's saying he has a cheap generator that uses
>> a cap for voltage regulation. They apparently do that by using
>> a cap in conjuction with the power source for excitation.
>
> I'm not sure how that works.
>
> The original AC voltage regulation system, which I think is called a Tillen
> regulator, and dates back to the 19th century, involves a buzzer that
> produces a square wave whose duty cycle is inversely proportional to the
> output voltage of the generator. This is integrated by a capacitor into
> a voltage that is inversely proportional to the output and that drives the
> field coil. This is how automotive alternators used to work until the
> seventies.
>
> (There is another method used with big generators that involves a DC
> motor generator set used to regulate the field coil, but we are talking
> small gensets here.)
>
> Anyway, the Tillen regulator is history and as far as I know nobody is
> using it today. Instead they use a solid state circuit whose output
> voltage is inversely proportional to the AC input voltage. Early on
> these used SCRs that acted as switching devices more or less like the
> Tillen mechanism, but by the 1970s they were mostly using big bipolar
> transistors. This is what I think the original poster is calling an
> "AVR" and it's pretty much how regular constant-speed AC generators work
> today.
>
> Now.... the interesting thing is that today we have a whole new breed
> of generators which are not constant speed. They generate AC, which is
> rectified and then used to power an inverter that creates constant
> frequency AC. This means the engine throttle can be adjusted to regulate
> voltage as well as the field coil... and it means the engine is throttled
> way back where it is quiet when there is little load and opened up all
> the way when there is more load. There's a lot more stuff inside the box
> to go wrong and some of the inverters are kind of crappy (although I am
> really amazed at how good a waveform and how little RF noise we get from
> the Honda 2000i), so repair and diagnosis is a little trickier.
>
> But if I were buying a baby generator (sub 5KVA) today, I would definitely
> go the inverter route. In the 5-20 KVA range it would depend.
>
>> But a better question might be
>> why would someone living in NYC, who has a critical need
>> to run CNC eqpt during a major power outage, be concerned
>> about spending $400 for decent voltage regulation? You think
>> that would have been in the decision for the generator from
>> the start.
>
> Personally, if I were running CNC equipment, I'd get out of NYC as fast as
> possible and get to a place with better support for manufacturing and lower
> tax rates...
> --scott
>

I believe you got your timeline a bit off on automotive generators. My
63 Dodge had an "alternator" with a transistorized voltage regulator. My
family had a 55 Chrysler which had a "generator" and electromechanical
voltage regulator. I do believe the GM cars from the 70's had the solid
state voltage regulator built into the alternator itself. ^_^

TDD

"jon_banquer" > wrote in message
...
On Feb 17, 8:23 am, "Existential Angst" > wrote:
> > wrote in message
>
> ...
> On Feb 17, 9:49 am, "Existential Angst" > wrote:
>
>
>
>
>
>
>
>
>
> > "Pete S" > wrote in message
>
> ...
>
> > >I don't understand your question.
> > > If you mean "capacitors" when you say "caps", I don't know how they
> > > would
> > > deal with output voltage regulation in any meaningful way.
>
> > Ditto. ergo my Q. I guess they must in some fashion, just like you
> > balance
> > rpc's with caps.
>
> > > What kind, model and serial number of genset do you have that
> > > currently
> > > has no voltage regulation built in to it?
>
> >http://www.generatorsales.com/order/...Generator.asp?...
> > modified for tri-fuel.
>
> > It is regulated, just not to 1 or 2%, a swing of 230 to 250 V, from 50+
> > amps
> > down to zero amps.
> > If you at mid-load it's 240 V, that's +/-10V, which is not terrible, but
> > it's not 1% either.
>
> > Assume no electrical-type regulation at all. There is something between
> > the
> > generator itself and the gas engine that ups fuel flow with load,
> > maintaining a semi-constant voltage.
>
> That would be the mechanical engine governor.
> ================================================== ==
>
> I sure would like to know the details on how those work.
>
> An AVR sharpens this up.
>
> Yes
>
>
>
> > I don't quite understand how this works, and part of the intent of Q was
> > to
> > shed some light on this.
>
> See my other post to a discussion.
>
>
>
> > I also figgered that if the feedback between generator and engine was
> > good
> > enough, AVR wouldn't be needed.
> > So basically I"m curious about the design of these things.
> > --
> > EA
>
> Do you realize what you got for $2800? They take a Honda
> engine and bolt it on to some generator made by someone
> else. Perhaps you can shed light on to who that someone
> else is, but given that it uses a cap for voltage regulation,
> I would not be surprised that it's a cheap Chinese one.
> Then they take pretty pictures of the thing with Honda showing
> all over in the pretty pics and a lot of people make the
> assumption that they are buying a Honda generator.
> I don't believe that is the case.
> ================================================== ===
>
> McCaulte (sp?) makes the generator.
>
> And yes, they mix'n'match.... but presumably they do it pretty well, altho
> I got a li'l short-shrifted on the AVR deal....
> I don't know that they are being misleading, as much as emphasizing the
> Honda part.... LOL
> Thin line, admittedly.
>
> Further arousing suspicion is that they claim it's 15KW.
> Then if you read the specs, it says it's rated at 13.5KW
> continuous.
> =============================================
>
> This is typical. Generac does this.
>
> Then they say it has a 50 amp main
> breaker, which equates to 12KW, in my world.
> ======================================
>
> Yeah, I noticed that. And they trip fast, too!
> I may put in my own 50 A slower-tripping or even 60 A breakers.
>
> You with me so far? Further arrousing suspicion, they
> quote fuel consumption in gallons, ie it's based on running
> the engine on gas. So, next, let's look at the spec for
> a Honda GX690. It says it produces 22hp running gasoline.
> I'm no expert in conversions from gasoline to nat gas, but
> AFAIK, when you run a gasoline engine on nat gas, you
> have about 15% less energy output. Maybe someone has
> the exact number. That means you really have about an
> 18hp engine.
> ===============================================
>
> Again, par for the course. I simply went for the most watts. Those watts
> will be similarly de-rated in most scenarios, so I just went with the
> biggest number.
>
> I've looked into generators a bit and what it takes to
> power them. I don't think you can get 15KW out of an
> 18hp engine. A Generac 12KW unit for example, uses
> a 26hp engine.
> ================================================
>
> Oh, but I did get very nearly the full 13.5 continuous (on gasoline), and
> proly could have gotten sig. more. I'll have to jump/replace the breaker,
> tho. Already at near-full load, it started a 26 gal compressor, w/ nary a
> hiccup.
>
> A 26 hp engine for 12 kW is suspect as well, from two povs:
> First, I suspect Generac hp is like Sears hp.
> Second, if it IS 26 hp, yer just sipping lots more gas.... which was one
> of
> the things I was going to discuss in my upcoming Generator Manifesto.....
> big-azz generators, in no-load conditions, are not economical.
>
> I really couldn't find much better overall bang fer the buck, watt-wise.
> The Honda motor is a plus, and the unit is VERY compact.
> Generacs are big and complicated. OK, I spose, for the home-moaner who
> justs likes to dial the telephone when sumpn goes wrong, and from what
> I've
> read about generac, they will be using their telephone fairly often.
>
> Here's some of my take on this:
>
> I would recommend the Sam's club 8,750 W blackmax, at $999, for most
> people
> with more than the basic needs. You can get it modified for tri-fuel, and
> the link I provided sells a modified blackmax for $1600 -- about a
> $200-$400
> preimum over what you would pay if you did it yourself, but with a lot
> less
> headache, and somewhat of a guarantee. The blackmax also has AVR, iirc,
> and
> performed quite well, before it grew feet.
>
> My unit does not come with a gas tank, but which is actually an advantage,
> imo, because you just drop the genset's hose down any gas can (or your
> car's
> gas tank, if you can snake it in), and Wala, gasoline power.
>
> I went for the 15 kW unit, in the second go-around, for many of the
> reasons
> you stated:
> By the time you get done de-rating for whatever whatever reasons, you
> have a lot less than when you started, so I figgered I'd just double the
> size from the gitgo.
>
> Really a lot of g-d work. The other bottom line to all this is that unless
> you have a water-cooled 4 cylinder unit, you gotta simply build a separate
> sound-proofed shed for these noise buckets.
> A lot of my work so far went in to testing, given my cnc liabilities. So
> far so good, but really a pita -- for sumpn I may NEVER use.
> --
> EA
>
> Just some more things to think about.

It seems it's often impossible to buy the right package for what
someone wants.
============================================

Amazing how that works.... in almost everything! From vitamins to cars to
cnc to real estate.....
Canada here I come.....



An example is an air compressor. I don't intend to run my air
compressor day in and day out so I don't have the need for a very
heavy duty dual stage air compressor pump like this one:

http://www.northerntool.com/shop/too...ct_42535_42535

I'd like this air compressor pump because it's got an 18 CFM rating at
90 PSI and it's got a decent price.

http://www.northerntool.com/shop/too...7235_200387235
================================================== ======

I'd be careful of Northern Tool. They are not above shenannigans.
I'd look at the displacement of the pistons, and try to guestimate the rpm,
and match that to cfm claims of similar sized compressors. Ahm no 'spert,
but 18 cfm at 90 psi seems pretty substantial. I'da thought more like 5 or 8
for that size.
I'd check out comparable sized Quincy's, or other reputable brands, and see
what they list.

The husky compressor is surprisingly civilized.






I'd like this motor:

http://www.northerntool.com/shop/too...6765_200306765

When I try an find a reasonably priced horizontal air tank I'm ****ed.
Prices are insane. Looks like my only choice will be to buy a used
horizontal air tank.
================================================== ==========

Well, mixing/matching is not a bad idea, and proly a really good one. Tanks
are tanks, motors are motors, so really what you want are a nice (quiet)
'pressor head, and a good regulator, with separate set points for
cut-in/cut-out, which bigbox stuff doesn't have.

Also, recall from a previous discussion that a big tank will help compensate
for smaller compressor size, and that instead of one big tank, a bunch of
small ones are the same as one big one, and a lot more manageable. I have a
bunch connected together, each one separately valved. You don't even need
the motor/'pressor mounted on a tank, per se.
I've even got some BBQ propane tanks I want to hook in, but goddamm, do they
make it difficult to remove dat stuff in the 3/4 neck. Also, there's no
drain, altho they are small enough you could put the drain on top, and just
tilt it to drain it.
--
EA