Genset voltage reg: capacitor vs. AVR

What are the pro's/cons of each?

One pro for caps is that they are cheaper! The AVR ditty for my unit would
cost another near-$400.
The pro for AVR is, presumably, much tighter voltage regulation with load.

But mebbe AVR has its limits ito ruggedness?

The voltage swing on my genset is 250 - 230 V, 0-50 A. Units with AVR
claim 1-2% regulation.

Should I spring for the AVR? If a major outtage occurs, I'll be running cnc
equpment from it.
--
EA

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.
What kind, model and serial number of genset do you have that currently has
no voltage regulation built in to it?

Pete Stanaitis
----------------

On Feb 16, 8:17*pm, "Pete S" > wrote:
> 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.
> What kind, model and serial number *of genset do you have that currently has
> no voltage regulation built in to it?
>
> Pete Stanaitis
> ----------------

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.

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.

And how could anyone forecast what regulation is required,
what the possible voltage swings might be, without knowing
what all the actual loads are, what their tolerance is, etc?

"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/...sp?page=H04599
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
> ----------------
>
>
>
>

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 ..

> wrote in message
...
On Feb 16, 8:17 pm, "Pete S" > wrote:
> 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.
> What kind, model and serial number of genset do you have that currently
> has
> no voltage regulation built in to it?
>
> Pete Stanaitis
> ----------------

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.
================================================

Except it's not so cheap. Which is why I was disappointed in the
regulation.
AVR IS available for the unit, they just chose to use caps..



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.
=============================================

I thought it did have AVR, and the point was, which you of course missed (in
your premature judgmental fervor), was *how much* better can AVR be expected
to improve things.... more of a general query as to how these things work.




And how could anyone forecast what regulation is required,
what the possible voltage swings might be, without knowing
what all the actual loads are, what their tolerance is, etc?
=================================================

That's the mfr's job. I in fact DID measure these things, whose values I
gave in the OP.

What size is YOUR generator, what fuel is used, and how well regulated is
it?
And what do you do about the noise? Or do you just let your neighbors
suffer?? lol
--
EA

On Sun, 17 Feb 2013 06:57:39 -0800 (PST), 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 ..

Without following this thread, it seems to me that he's looking at a
filter circuit for suppressing voltage spikes rather than a voltage
regulator.

I'll leave it to you to comment.

--
Ed Huntress

> 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

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

"Robert" > wrote in message
...
> 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 ..

OK.....

I am actually reciting what the company told me.
Apropos of your comment (and Pete's confusion, as well), what I think they
actually meant was that the caps are used to TUNE or balance the system,
somewhat like you would the legs of a 3 ph rotary converter -- which I do
all the time.

As I mentioned above, the "first stage" of regulation is accomplished via
some linkage between the generator and the motor, as in gas powered
welders -- which I've always been curious about how that works.
AVR would then seem to improve this.

Not sure how all this occurs, just exploring the idea of tighter regulation.

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

"Scott Dorsey" > wrote in message
...
> > 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.

Which is what cars do, right?

In generators, I think they call it automatic idle, in the better units.

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.

There's also the issue of "true sine" vs. std inverter output. True sine is
sig'ly more expensive.

>
>>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...

AMEN!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Hopefullyl they'll let me into VanCouver, BC, Canada.... LOL

fuknBloomberg has no sympathy for people unwilling/unable to spend $1 mil on
a 1 BR apt, whose rent (before he and Guiliani gutted rent control) was
proly $500/mo.

"Buying" apts. is essentially mega "key money", which is illegal.
But when sed key money allows you to "flip" a hot potato to some other
sucker, which generates all kinds of minicipal revenue, then I guess it's
ok.....

Parts of NYC used to be machining meccas, partic. in the small parts
industry (spring-making, lighting, for example), and in knitting. Pre-1990,
parts of Brooklyn, Queens were the knitting capital of the world, I'm told,
with a large machining infrastructure (mom&pop machining, btw) to make the
many *very* intricate parts that would wear in the needle/knitting process.
--
EA


> --scott
>
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."
>