More generator Q's

Those are over-excited synchronous motors.

Reply to
Don Foreman
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...As long as it isn't late Saturday night and you're in the boondocks. My trunk is lighter these days, however, without two stuffed toolboxes in the trunk.

Reply to
Ed Huntress

(...)

I'll make that trade! I spent many lost weeknights and weekends under the hood so that I could make it to work the next day. Fergit that, man! :)

Let us not forget the blessing of the Onboard Diagnostics! When things (rarely) do go pear-shaped, the OBD is a heck of a time saver. Imagine troubleshooting an intermittent sensor problem without it. (Shudder)

As is mine! (Though the boxes remained in the trunk a while before I noticed that my Japanese - designed car wasn't failing.)

Reliability leads to better gas mileage. Who knew?

--Winston

Reply to
Winston

For UK residents but may apply elsewhere. The old analogue electric power meters happily spun forwards or backwards to read power consumed or power fed back into the supply. In the UK the supply authorities are now replacing them with digital meters that are programmed NOT to register negative power. Power fed back into the supply will be happily accepted by the supply authority but will not reduce the meter reading.

Not sure why they are programmed this way but the effect with many Solar PV tariffs is to reduce the claimed saving In the nett electricity bill. Power that is registered outside daylight hours cannot be reduced or cancelled by daylight solar energy.

Jim

Reply to
pentagrid

Small wind turbine typically produce multiphase energy that is converted to DC and then runs a solid-state co-gen inverter system to grid tie and synchronise.

Here is another quote from another method used on larger units. The doubly fed generator bleeds a small bit of ac power off the utility grid and converts it to a signal that creates the wound rotor?s magnetic field at low wind speeds, when the generator is spinning at below its synchronous speed. Fast electronics control the spinning rotor?s magnetic field such that the generator puts out a 60-Hz signal even when it is turning slowly. (Above synchronous speed, the rotor of doubly fed generators produce power to the grid.)

------------------------------------------ "PrecisionmachinisT" wrote in message news:Q5CdnZE3QNK5-eXQnZ2dnUVZ snipped-for-privacy@scnresearch.com... Not sure about the 3660 poles per second part but pretty sure just about every windmill that is placed onto the grid does exactly this.

Reply to
Josepi

Nice.

How do you excite the windings ?

I have had the Nigel Smith book for nearly a decade now-actually bought the thing--if there is a prolonged power outage here what I do is I run a 50 hp

3ph motor as a single phase induction generator off from my 23 hp kubota tractor PTO--which easily powers the entire house including starting a 5 ton heat pump compressor..

C2C connection gives you single phase off of a 3 phase motor, rpm ( 60 hz ) is via throttle governor and isnt particularily critical, 20% is probably okay but if in doubt use a ole telechron clock, and compare with a quartz unit..they bothe should read within a few seconds after a minute's time on line...if not, then adjust your throttle to suit.

Reply to
Josepi

I haven't ran into that situation here. I doubt it would be approved...yet...until somebody thinks of it...shhhhhhh.

It would make sense as they do not want your extra energy in off peak hours. They are try to give the stuff away, already.

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Not sure why they are programmed this way but the effect with many Solar PV tariffs is to reduce the claimed saving In the nett electricity bill. Power that is registered outside daylight hours cannot be reduced or cancelled by daylight solar energy.

Jim

Reply to
Josepi

The brilliance (using the term loosely) is proportional to voltage^3.5. In other words, a small change in voltage results in a relatively large change in "brilliance".

Reply to
Ned Simmons

I know it is not completely linear to the square of the voltage, as the filament is a dynamic resistance, but where did you get the 3.5 exponent?

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On Thu, 10 Mar 2011 09:22:13 -0500, "Josepi" wrote: Yes, having two light bulbs with one as a standard could help your estimation of brilliance providing you knew the "standard" one was being powered by exactly the rated voltage. Since power is proportional to the square of the applied voltage the power and therefore the brilliance could be somewhat off for the purposes of good measurement.

Reply to
Josepi

That's inneresting -- from Stefan-Wien's law or sumpn?? Blackbody radiation?

So this would make comparative brilliance not such a bad indicator -- mebbe why optical pyrometers were pretty accurate?

But, any way you cut -- monitoring brilliance or voltage -- yer error is a whole lot less than this confabulated bullshit in the fitness market.

Reply to
Existential Angst

Lotus 7, huh. I remember going to a British car dealer in the 1960's to check out a '7' and I could not get my feet down to where the peddles were. I suppose if I took my shoes off, it would work. I dearly wanted to test drive that car.

Oh, well. In reality, we couldn't afford it.

Paul

Reply to
KD7HB

I'm 5'9" and have a couple of friends with old Lotuses (Super 7 America Mk IV, and a '63 Elan). They're just made for me. I think it was _Car & Driver_ that described the seats in the Super 7 Mk IV: "The word often used to describe supportive seating in a sports car is 'caress.' These seats are more like being gripped in the jaws of an enraged clam."

The Lotus 6 had a plank for a seat with a piece of canvas, or maybe an old T-shirt, glued to it. It weighed around 950 pounds, dry.

However, even I feel claustrophobic in a Lotus Europa. If you're over 5'11", your head squashes the headliner. No kidding.

I debated over a Super 7 in 1967, and again in '72. But I had to drive between NJ and Michigan in those days, and winter driving made it too unappealing. The Super 7 in kit form was $2,800 in '67. I don't know what the assembled price was, but you could bolt one together over a couple of weekends.

Reply to
Ed Huntress

From memory (I knew the exponent was approx 4), confirmed by Wikipedia. Fink's "Standard Handbook for Electrical Engineers" says

3.38.
Reply to
Ned Simmons

hmmm... sounds way too high, at first.

If the filament was a straight fixed resistor the power would be the square of the voltage only.

Since the filament increases resistance with heat the resistance is not constant and would decrease the voltage squared factor to less than 2. It should be noted that the resistance is probably not linearly proportional to the power as there is heat leakage factors and irradiation that will affect the linearity of that too.

Now we are talking about brilliance of illumination and not power per se, so another conversion factor enters into it.

DO we know (any links) what the relationship of a filament bulb lumens output to power in is. There should be some charts. If we can establish it has an almost squared element (pun noted) then we can basically verify this

3.38 or something to that effect.

Sounding more reasonable all the time and would make a light bulb a really sensitive power level indicator. Especially when compared to a standard known illumination.

Thanx for the info!

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3.38.

On Thu, 10 Mar 2011 11:12:05 -0500, "Josepi" wrote: I know it is not completely linear to the square of the voltage, as the filament is a dynamic resistance, but where did you get the 3.5 exponent?

Reply to
Josepi

Existential Angst wrote in rec.crafts.metalworking on Tue, 8 Mar 2011 23:24:34 -0500:

Should be spelled "All".

You would like the 'book' _alternator secrets_ . Covers automotive alternators mostly, but has a section on using induction motors as generators. I got my copy from lindsay publications.

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From what I remember, you may need to hit the windings with some current to get things started. A car battery should do, just for a second.

Reply to
dan

Not true, or only a little so. A 3 Ph induction motor WILL output power to the grid, WHEN RUN OVER SYNCHRONOUS SPEED. THis is NOT a rotating capacitor! It will still be "consuming" reactive power (vars) just like it was when running as a motor. This is an induction generator. THey are commonly found in wind turbines, and pumped storage systems.

A rotating condenser (capacitor) is a SYNCHRONOUS motor that is excited past unity power factor on it's field winding. [i.e. more excitation than needed when running as a motor] it is rotating at exactly synchronous speed. Attempt to rotate it faster (by sticking a primer mover on it) and you have a generator. Put a load on the shaft and you have a motor.

jk

Reply to
jk

2 Capacitors

Reply to
PrecisionmachinisT

Not in an incandescant lightbulb.

Reply to
Don Foreman

Lightbulbs are not a linear load. Their resistance goes up as the voltage increases. You would need to monitor the voltage and the current to get anything useful.

Reply to
Michael A. Terrell

Do you have any links for information along those line? . I never worked on "rotating capacitors" for power factor correction usage and would find that interesting . Mostly I worked with smaller motors under 5HP, transformers and transmission lines and communication stuff. The few PH correction capacitors we had were static units under 60 MVARs and I would think the protection circuits would be simpler.

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A rotating condenser (capacitor) is a SYNCHRONOUS motor that is excited past unity power factor on it's field winding. [i.e. more excitation than needed when running as a motor] it is rotating at exactly synchronous speed. Attempt to rotate it faster (by sticking a primer mover on it) and you have a generator. Put a load on the shaft and you have a motor.

"Josepi" wrote: This is nicknamed "rotating capacitor" by some electric utilities and used to correct power factor on lines and systems.

Reply to
Josepi

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