Magnetic circuit simulation request

"m II" apparently doesn't know how PWM-ing works. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

WRONG!

--
"Design is the reverse of analysis" 
                   (R.D. Middlebrook)

"m II" is clueless about how PWM and flyback diodes work. Let him become another Darwin Award candidate ;-) ...Jim Thompson

-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at

| 1962 | I love to cook with wine. Sometimes I even put it in the food.

If the wind dictates that the rpm stays the same, the only other variable is the field current. Rpm and field current are the only variables given the same state of charge in the battery.

mike

--
It is hard enough to remember my opinions, without also remembering my 
reasons for them! 
--Friedrich Nietzsche

Suggested reading:

Regards

Klaus

EXCELLENT! Thank you, Klaus. Perhaps you can answer one question with regard to that paper's discussion of temperature compensation. At high temperature, the voltage to the battery is turned down to PREVENT the battery boiling over [that I understand], but what I missed was any mention of the relationship between the battery's voltage and temperature. Did I miss? What I mean is that lead-acid battery's voltage drops with temperature, to something like 8 volts at low temps and climbs to something like 14+ V at high temp and that effect would seem to help compensate for the other effect, that is the battery cannot take as much 'power' at high temperature and can take more 'power' at low temperature. However, the curve shown for temperature compensation seemed a bit extreme without any inclusion of what the battery is doing.

QUESTION in general: Why are wind generator blades shaped like giant propellers and NOT squirrel cage shapes? From logic it would seem that the best shape would be to follow what the fan makers discovered, that the best transfer of energy occurs with the squirrel cage shape and not the standard 'fan' shaped blades. Not being astute at fluidic energy transfer, could not work this out for self.

ARRRGGG! Why is the best way to discover the answer to ANY question is to first pose it on the internet, embarrass oneself with stupidity, and THEN see the solution!

ANSWER: The squirrel cage is BEST for working against head pressure and the standard blade is best for 'free' flowing air.

Is that it?

I broke down and actually did some research. I was wrong. It would appear that even in this enlightened era, there are such things as 'pulsating contacts' and dumping amperage to ground to divert it from reaching the battery. Unbelievable.

My only excuse (and humble attempt to redeem myself) is that I live in a small town and sometimes it takes decades for new information to reach us. This year of 1972 is finding me in good health.

mike

--
It is hard enough to remember my opinions, without also remembering my 
reasons for them! 
--Friedrich Nietzsche

A centrifugal blower the size of your average wind generator would be quite the installation!

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC 
Optics, Electro-optics, Photonics, Analog Electronics 

160 North State Road #203 
Briarcliff Manor NY 10510 

hobbs at electrooptical dot net 
http://electrooptical.net

Shorting out an alternator reduces the drag, so it isn't as bad as you'd think. Heating a zener is another matter.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC 
Optics, Electro-optics, Photonics, Analog Electronics 

160 North State Road #203 
Briarcliff Manor NY 10510 

hobbs at electrooptical dot net 
http://electrooptical.net

Field current controls output voltage, not output current, ergo your original statement is incorrect.

Lead-acid batteries need a current-limited, constant voltage, charge. Automobile alternators self-limit on current, and employ some sort of feedback control of voltage by controlling field current. DC regulation in earlier times, more efficient PWM, now. Most of the time, an automotive alternator is supplying vehicle electrical loads, with only a small proportion of its output going into the battery.

If only 'twere true that the wind dictated that the RPM stays the same. Wind speed varies from minute to minute. A combination of inertia, and careful blade design, even variable-pitch, and governors, are necessary to ensure even approximately constant speed. At low RPM, and high field excitation, the turbine might not supply enough torque to turn the generator.

A battery designed for automotive starting service is quite different to one designed for cyclic use. Look at the differing curves published by battery manufacturers. Different constructions require different charging profiles.

--
"Design is the reverse of analysis" 
                   (R.D. Middlebrook)

Not in an alternator. An alternator, for instance for Spice purposes, may be considered an "F" device >:-}

...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

n

e

,

Talking about wind turbines, some of the actually use what is called double fed generators. The function is much like the alternator. A sine shaped fi eld current determines the output from the generator. The output frequency of the generator is the difference of the shaft frequency and the rotor cur rent frequency

Cheers

Klaus

It is actually a classical mixing. You'll get both sum and difference of the excitation and shaft frequencies.

--

-Tauno

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uble fed generators. The function is much like the alternator. A sine shape d field current determines the output from the generator. The output freque ncy of the generator is the difference of the shaft frequency and the rotor current frequency

Thanks, didn't know that (I was on a "need to know basis") ;-)

Cheers

Klaus

only if the rotor is single-phase with a polyphase rotor you can do SSB mixing and produce a single output frequency.

It seems that if the rotor leads the output frequency this would generate energy in both the rotor windings.

--
?? 100% natural 

--- news://freenews.netfront.net/ - complaints: news@netfront.net ---

Field current puts a hard limit on output current.

Once the output current times the output turns count matches the input current times the input turns count the magnetic field is nulled and no voltage is produced.

--
?? 100% natural 

--- news://freenews.netfront.net/ - complaints: news@netfront.net ---

Naturally. Below this limit, voltage is a function of field current.

Automotive alternators limit at tens of amps. Fine for a discharged starting type battery with the lights on. Not so fine for batteries designed for cyclic service.

The OP seems to want to stuff 60 amps into his batteries, irrespective of state of charge. Not a good idea.

--
"Design is the reverse of analysis" 
                   (R.D. Middlebrook)

In a generator, the rotor phase always leads (torque angle) the (loaded) output phase.

The same principle in reverse can be used to make an unloaded, over-excited, synchronous motor look like a capacitor.

--
"Design is the reverse of analysis" 
                   (R.D. Middlebrook)