Genset voltage reg: capacitor vs. AVR

Anybody can make a spelling or grammar mistake or a simple typo in a
usenet post, but why would anyone do so intentionally?


--
There is always an easy solution to every human problem -- neat,
plausible, and wrong." (H L Mencken)

Larry Wasserman - Baltimore Maryland - lwasserm(a)sdf. lonestar. org

On Feb 19, 1:48*am, "Existential Angst" > wrote:
> "jon_banquer" > wrote in message
>
> ...
> On Feb 17, 10:00 pm, jon_banquer > wrote:
>
>
>
>
>
>
>
>
>
> > On Feb 17, 9:50 pm, jon_banquer > wrote:
>
> > > On Feb 17, 9:40 am, "Existential Angst" > wrote:
>
> > > > 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
>
> > > I'm hearing almost all air compressor pumps are made in either China
> > > or India. That includes Ingersoll Rand. Thinking that Northern Tool
> > > may not be the way to go. Found this. Like the price and the specs:
>
> > >http://www.eatoncompressor.com/catal...43/1320611.htm
>
> >http://wiki.answers.com/Q/Are_Ingers...ade_in_the_USA
>
> Spoke with Eaton compressor at length today. Person I spoke with was
> very knowledgeable and no bull****. Their air compressor pumps have
> been made in China for the last 12 years. They have dual suppliers in
> China and the parts are interchangeable. They stock all the parts. I
> like how the compressor pump I'm interested in runs at low RPM (850),
> is 25 CFM (@90 PSI) and sells for $500. The also sell Lincoln electric
> motors which are owned by Leeson. 7 1/2 HP Lincoln motor is $550. $65
> for a pulley. Square D mag starter is $170. Pressure switch is $40.
> Don't think I'm going to need multiple tanks. What do you see as the
> benefit to multiple tanks if you have the right compressor to keep up
> with your needs?
> ================================================== ===========
>
> True, a good compressor does not require my staged tank strategy, but imo,
> increasing tank capacity will extend the usable cfm rating of any
> compressor, AND reduce it's cycling.
>
> This is more important if you are going on the cheap, or have limited power,
> or space. *I got my 26 gal Husky as a floor model for $160 at HD, and just
> added extra tanks as I stumbled across them -- could even be tall welding
> tanks!
> Dat 7.5 hp motor is going to dim the lights!
> You can also save on the contactor by just using a simple relay, with the
> coil wired into the pressure switch.
> For me, space is at a premium, portability is really helpful.
> And even a 26 gal Husky (vertical) is heav-eeeeee!! *Holy ****.....
> Also make sure it's easy to drain the tanks. *I run a long hose from the
> bottom, with a small ball valve at the end of the hose (1/4" white stuff,
> like for a fridge's ice-maker), and just empty it into a bucket.
>
> If you are going to mix'n'match, $550 for a motor seems like a lot, I would
> go to a motor re-winding place, and see what they have on their shelves, for
> cheap. *They often have *hundreds* of spare motors to choose from, I'll bet
> you could find sumpn suitable for under $100, mebbe way under.
>
> Finagling "small" has its advantages. *For example, if you have limited
> power, and are running cnc, you don't want big-azz motors causing transient
> voltage drops every time the pressor kicks in. *So a smaller motor/pressor
> is less electrical strain, and larger tank volume creates less cycling,
> jolts to the electrical service.
> Which also becomes even more important during outtages, if running off a
> generator.
> And also ito moving **** around...
>
> If none of this is a factor, then you can go big and heavy and strong, but
> if it is a factor, finagling small stuff helps -- a kind of "modularity".
> --
> EA

"This is more important if you are going on the cheap, or have limited
power, or space."

We both have a limited space problem.

Would something like this help you?

https://www.benchsolution.com/products/workbench/

On Feb 19, 4:40*pm, (Scott Dorsey) wrote:
> > wrote:
>
> >Which would mean to me that you could run a generator with a bad or
> >incorrectly adjusted governor running at 3400 RPPM, or 4000 RPM
> >and the only thing that would change is that the frequency would not
> >be 60hz, ie the voltage stays the same. * That isn't true, because the
> >voltage is directly proportional to the speed too. *I agree that
> >adjusting
> >the field is how the voltage is adjusted without changing the engine
> >speed.
>
> But you CAN run the generator at some other speed and the output voltage
> will be the same. *Try it! *That's the purpose of the feedback control of
> the field coil. *The faster you run the thing, the more the regulator
> will drop the voltage of the field coil. *It completely decouples the operating
> speed from the output voltage.

Yes, IF the speed deviation is within the range of whatever
the voltage regulator is capable of maintaining.



>
> >I posted a link to a discussion on the subject previously.
> >Apparently capacitors are used as a cheap voltage regulator.
> >Also, just google and you'll find info.
>
> This is just handwaving. *What is actually going on? *The capacitor can
> be used to shift the phase of a signal, it can be used as part of a resonant
> tank. *What is the capacitor _doing_ in this magic circuit?
>
> I have googled and I have seen nothing particularly useful, unfortunately..
> --scott
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."

I agree that I haven't seen a technical description of how they
work. But there is enough info from some google searches
that shows that caps are used as voltage regulators in basic
generators.

"jon_banquer" > wrote in message
...
On Feb 19, 1:48 am, "Existential Angst" > wrote:
> "jon_banquer" > wrote in message
>
> ...
> On Feb 17, 10:00 pm, jon_banquer > wrote:
>
>
>
>
>
>
>
>
>
> > On Feb 17, 9:50 pm, jon_banquer > wrote:
>
> > > On Feb 17, 9:40 am, "Existential Angst" > wrote:
>
> > > > 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
>
> > > I'm hearing almost all air compressor pumps are made in either China
> > > or India. That includes Ingersoll Rand. Thinking that Northern Tool
> > > may not be the way to go. Found this. Like the price and the specs:
>
> > >http://www.eatoncompressor.com/catal...43/1320611.htm
>
> >http://wiki.answers.com/Q/Are_Ingers...ade_in_the_USA
>
> Spoke with Eaton compressor at length today. Person I spoke with was
> very knowledgeable and no bull****. Their air compressor pumps have
> been made in China for the last 12 years. They have dual suppliers in
> China and the parts are interchangeable. They stock all the parts. I
> like how the compressor pump I'm interested in runs at low RPM (850),
> is 25 CFM (@90 PSI) and sells for $500. The also sell Lincoln electric
> motors which are owned by Leeson. 7 1/2 HP Lincoln motor is $550. $65
> for a pulley. Square D mag starter is $170. Pressure switch is $40.
> Don't think I'm going to need multiple tanks. What do you see as the
> benefit to multiple tanks if you have the right compressor to keep up
> with your needs?
> ================================================== ===========
>
> True, a good compressor does not require my staged tank strategy, but imo,
> increasing tank capacity will extend the usable cfm rating of any
> compressor, AND reduce it's cycling.
>
> This is more important if you are going on the cheap, or have limited
> power,
> or space. I got my 26 gal Husky as a floor model for $160 at HD, and just
> added extra tanks as I stumbled across them -- could even be tall welding
> tanks!
> Dat 7.5 hp motor is going to dim the lights!
> You can also save on the contactor by just using a simple relay, with the
> coil wired into the pressure switch.
> For me, space is at a premium, portability is really helpful.
> And even a 26 gal Husky (vertical) is heav-eeeeee!! Holy ****.....
> Also make sure it's easy to drain the tanks. I run a long hose from the
> bottom, with a small ball valve at the end of the hose (1/4" white stuff,
> like for a fridge's ice-maker), and just empty it into a bucket.
>
> If you are going to mix'n'match, $550 for a motor seems like a lot, I
> would
> go to a motor re-winding place, and see what they have on their shelves,
> for
> cheap. They often have *hundreds* of spare motors to choose from, I'll bet
> you could find sumpn suitable for under $100, mebbe way under.
>
> Finagling "small" has its advantages. For example, if you have limited
> power, and are running cnc, you don't want big-azz motors causing
> transient
> voltage drops every time the pressor kicks in. So a smaller motor/pressor
> is less electrical strain, and larger tank volume creates less cycling,
> jolts to the electrical service.
> Which also becomes even more important during outtages, if running off a
> generator.
> And also ito moving **** around...
>
> If none of this is a factor, then you can go big and heavy and strong, but
> if it is a factor, finagling small stuff helps -- a kind of "modularity".
> --
> EA

"This is more important if you are going on the cheap, or have limited
power, or space."

We both have a limited space problem.

Would something like this help you?

https://www.benchsolution.com/products/workbench/
================================================== ======

Mebbe in a Leave-It-To-Beaver shop world..... lol
In MY world..... lessee, how to describe it....

The only way I can find a pencil in my shop is to buy a gross (or two) and
throw all 144 of them up in the air, throughout the shop. THEN mebbe I'll
be able to find a pencil somewhere.
Ditto flashlights, tape measures, calipers, you name it. I now have OVER 30
small led flashlights ( HD 8-packs, about $10, batts included) throughout
the house/shop -- and finding a flashlight is STILL hit and miss!!!

Funny, I built a drop-down welding table almost exactly like that, with
shelving on top, when I was still parking <gasp> CARS in the garage -- how
silly was DAT???
So I figgered Oh, Gee, I'll just drop down the table to park the cars....
Yeah, right.....
Dat drop-down welding table was dropped down exactly ONCE (to show the
wife), and was never ever deopped down again!! Cuz, well, dropping down
the table would mean..... <GASP> ..... CLEANING UP!!!! LOL
'tis the Nature of the Shop Beast.

**** like dat is for Tool Time, or This ole House..... or shop teachers in
a well-funded school. Noble-ly ideal, but just not in the reality of The
Frazzled and The Cramped. Heh, and The Broke.

It DOES look beautiful, tho.
But it's sorta like exercise equipment/gadgets that store under yer bed.....
Guess what.... they then STAY under the bed. lol

I eventually took my drop down welding table out altogether and made it
REALLY useful:
I parked it on some milkcrates -- stacked three-high -- which is a li'l
tip for Iggy and his ridiculous 30" high welding tables. goodgawd.....

Which I really shouldn't knock......
cuz all those mutha****as dumb enough to weld on his 30" welding table
will be calling Moi up for my apparatus/bars to stretch out/invert their
aching mis-aligned backs. Heh, I should send Ig a commission, eh?
Well, I will, but AFTER he sends the whole of RCM a commission check for the
*unending* (free) business advice he solicits ad nauseum.
--
EA

"Larry W" > wrote in message
...
> Anybody can make a spelling or grammar mistake or a simple typo in a
> usenet post, but why would anyone do so intentionally?

My phonetic rebellion..... no more o-u-g-h's for me -- enuf is enuf.

>
>
> --
> There is always an easy solution to every human problem -- neat,
> plausible, and wrong." (H L Mencken)

Einstein:
**** should be made a simple as possible.... but no simpler.

Einstein:
If you think **** is simple, then you really don't understand ****.
--
EA




>
> Larry Wasserman - Baltimore Maryland - lwasserm(a)sdf. lonestar. org

On Feb 19, 4:56*pm, Transition Zone > wrote:
> On Feb 19, 1:54*pm, (Scott Dorsey) wrote:
>
>
>
> > > wrote:
> > >On Feb 18, 11:12=A0am, (Scott Dorsey) wrote:
> > >> > wrote:
> > >> With a conventional AC generator, the speed of the engine governs the
> > >> output frequency. =A0The generator HAS to run at constant speed, usually
> > >> 1800 rpm, in order to get 60 Hz out of the generator. =A0Change the engin=
> > >e
> > >> speed, you change the line frequency.
>
> > >No **** sherlock and you also change the voltage.
>
> > Possibly for one fraction of a cycle, but as soon as there is any change, the
> > field coil voltage will be increased to compensate for it. *The mechanical
> > feedback loop that controls the engine speed is very very slow, because it
> > is limited by the inertia of the engine an the rotor. *The electrical feedback
> > loop that controls the field coil voltage is pretty fast; it is limited
> > mostly by the inductance of the field coil.
>
> > >> This is why conventional AC generators ALL have a device to regulate the
> > >> field coil voltage in order to get constant output voltage. =A0Some of th=
> > >ese
> > >> devices are better than others.
>
> > >That's true and why EA is asking about a cap versus
> > >a ture electronic voltage regulator.
>
> > And what does he mean by "a cap?" *As I said earlier, you have two choices
> > for voltage regulation: a feedback loop controlled by a mechanical buzzer, or
>
> *>a feedback loop controlled by a solid state device. * What is this
> mysterious
>
> > *"capacitor regulation" that he has come up with?
>
> A cap is a given as a capacitor. You regulate voltage, raising it
> means you lower its current. Increasing the current means you can run
> something faster, like a fan, but you lower the voltage, so you are
> regulating it in that sense. *But the power is what always remains the
> same (assuming reaction in the circuit isn't a factor).- Hide quoted text -
>
> - Show quoted text -


Sigh.....

> wrote:
>
>I agree that I haven't seen a technical description of how they
>work. But there is enough info from some google searches
>that shows that caps are used as voltage regulators in basic
>generators.

Okay, here is the story! All of the details can be found in US Patent
4,269,368.

Looking at how this works, it's not a conventional brush-type alternator at
all, but an induction device almost like an induction motor in reverse. The
patent shows a single pole rotor with a diode across the winding, so the
rotor acts as a magnetic short in one direction and a magnetic open in the
other. This diode is really the key to the trick.

Now, the stator has two windings, physically 90 degrees apart. One winding
is the load winding, the other is the field coil itself, and the field coil
has a capacitor across it.

When the first pole of the rotor passes by, it induces a current in the
field winding that is proportional to the current passing through the
load coil (ie. proportional to the load being drawn). Then that pole
continues on and in the next 180 degrees of rotation induces a current
proportional in the load winding that is proportional to the current in
the field coil across the capacitor.

You can think of this not as an AC generator but as a device that creates
pulsed DC... the waveform is going to be very asymmetric. But, the amount
of voltage induced in the load coil should stay more or less sort of constant
with the current draw on it.

It really is a cheesy kind of trick, and I am not sure I'd want to use a
generator like this to run anything more sophisticated than an induction
motor, but there are plenty of folks out there who need to run induction
motors.

The capacitor isn't doing the regulation, it's just storing energy to keep
the field coil running.... the diode isn't doing the regulation, it's just
making sure the coils are both excited only in one direction.... it's the
design of the whole thing that is doing the regulation. Calling this
"capacitor-regulated" is incorrect but "capacitor-excited" is more like it.

I've never actually seen this before and the whole idea is just kind of
ingenious. The patent dates back to 1981 so this has clearly been in use
for a while. My guess is that in real life there are a bunch of poles on
the rotor with an individual diode for each pair, but I've never taken one
apart.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On Feb 20, 7:58*am, " >
wrote:
> On Feb 19, 4:56*pm, Transition Zone > wrote:
>
>
>
>
>
>
>
>
>
> > On Feb 19, 1:54*pm, (Scott Dorsey) wrote:
>
> > > > wrote:
> > > >On Feb 18, 11:12=A0am, (Scott Dorsey) wrote:
> > > >> > wrote:
> > > >> With a conventional AC generator, the speed of the engine governs the
> > > >> output frequency. =A0The generator HAS to run at constant speed, usually
> > > >> 1800 rpm, in order to get 60 Hz out of the generator. =A0Change the engin=
> > > >e
> > > >> speed, you change the line frequency.
>
> > > >No **** sherlock and you also change the voltage.
>
> > > Possibly for one fraction of a cycle, but as soon as there is any change, the
> > > field coil voltage will be increased to compensate for it. *The mechanical
> > > feedback loop that controls the engine speed is very very slow, because it
> > > is limited by the inertia of the engine an the rotor. *The electrical feedback
> > > loop that controls the field coil voltage is pretty fast; it is limited
> > > mostly by the inductance of the field coil.
>
> > > >> This is why conventional AC generators ALL have a device to regulate the
> > > >> field coil voltage in order to get constant output voltage. =A0Some of th=
> > > >ese
> > > >> devices are better than others.
>
> > > >That's true and why EA is asking about a cap versus
> > > >a ture electronic voltage regulator.
>
> > > And what does he mean by "a cap?" *As I said earlier, you have two choices
> > > for voltage regulation: a feedback loop controlled by a mechanical buzzer, or
>
> > *>a feedback loop controlled by a solid state device. * What is this
> > mysterious
>
> > > *"capacitor regulation" that he has come up with?
>
> > A cap is a given as a capacitor. You regulate voltage, raising it
> > means you lower its current. Increasing the current means you can run
> > something faster, like a fan, but you lower the voltage, so you are
> > regulating it in that sense. *But the power is what always remains the
> > same (assuming reaction in the circuit isn't a factor).- Hide quoted text -
>
> Sigh.....

Oh, and with a split-phased capacitor, part of one phase can be used
to help start a motor before its brought back to normal running the
motor.

On Feb 21, 11:35*am, Transition Zone > wrote:
> On Feb 20, 7:58*am, " >
> wrote:
>
>
>
>
>
> > On Feb 19, 4:56*pm, Transition Zone > wrote:
>
> > > On Feb 19, 1:54*pm, (Scott Dorsey) wrote:
>
> > > > > wrote:
> > > > >On Feb 18, 11:12=A0am, (Scott Dorsey) wrote:
> > > > >> > wrote:
> > > > >> With a conventional AC generator, the speed of the engine governs the
> > > > >> output frequency. =A0The generator HAS to run at constant speed, usually
> > > > >> 1800 rpm, in order to get 60 Hz out of the generator. =A0Change the engin=
> > > > >e
> > > > >> speed, you change the line frequency.
>
> > > > >No **** sherlock and you also change the voltage.
>
> > > > Possibly for one fraction of a cycle, but as soon as there is any change, the
> > > > field coil voltage will be increased to compensate for it. *The mechanical
> > > > feedback loop that controls the engine speed is very very slow, because it
> > > > is limited by the inertia of the engine an the rotor. *The electrical feedback
> > > > loop that controls the field coil voltage is pretty fast; it is limited
> > > > mostly by the inductance of the field coil.
>
> > > > >> This is why conventional AC generators ALL have a device to regulate the
> > > > >> field coil voltage in order to get constant output voltage. =A0Some of th=
> > > > >ese
> > > > >> devices are better than others.
>
> > > > >That's true and why EA is asking about a cap versus
> > > > >a ture electronic voltage regulator.
>
> > > > And what does he mean by "a cap?" *As I said earlier, you have two choices
> > > > for voltage regulation: a feedback loop controlled by a mechanical buzzer, or
>
> > > *>a feedback loop controlled by a solid state device. * What is this
> > > mysterious
>
> > > > *"capacitor regulation" that he has come up with?
>
> > > A cap is a given as a capacitor. You regulate voltage, raising it
> > > means you lower its current. Increasing the current means you can run
> > > something faster, like a fan, but you lower the voltage, so you are
> > > regulating it in that sense. *But the power is what always remains the
> > > same (assuming reaction in the circuit isn't a factor).- Hide quoted text -
>
> > Sigh.....
>
> Oh, and with a split-phased capacitor, part of one phase can be used
> to help start a motor before its brought back to normal running the
> motor.- Hide quoted text -
>
> - Show quoted text -

Sigh.... None of which has any relevance to how a cap is used
to regulate voltage in a cheap generator.

"Scott Dorsey" > wrote in message
...
> > wrote:
>
> Looking at how this works, it's not a conventional brush-type
> alternator at
> all, but an induction device almost like an induction motor in
> reverse. The
> patent shows a single pole rotor with a diode across the winding, so
> the
> rotor acts as a magnetic short in one direction and a magnetic open
> in the
> other. This diode is really the key to the trick.
>

http://en.wikipedia.org/wiki/Magnetic_amplifier
"A relatively small DC current on the control winding is able to
control or switch large AC currents on the AC windings. This results
in current amplification."