Roto Verter

[theremart]

Horse power for alternator...

Calculation for an alternator horsepower...
FAQ

How much horsepower loss
will an alternator cost ?

As was stated in the answer to the first question, an alternator is a power converter. It converts mechanical power into electrical power. So it doesn't lose power, but rather changes its form. No electrical motor or generator is 100% efficient and this is true of alternators as well. Alternators are about 85% efficient with power being lost in the form of heat and wind resistance (cooling fans). Thus the real power loss of the alternator is relatively small.

How much horsepower does an alternator pull ? You can mathematically determine the horsepower cost at any given load. (Remember, alternators respond to load. If there is no load present the alternator is basically freewheeling.)

Amps x Volts = Watts
Watts / 745.7 (one HP) = Electrical HP Produced by the Alternator
HP x 15% Efficiency Loss = HP Loss
HP + HP Loss = Total HP Used

Example:
57A x 14.9V = 849.3 Watts
849.3 Watts / 745.7 = 1.14 HP
1.14 HP x 15% = 0.17 HP
1.14 + 0.17 = 1.31 HP Total

Now we know the cost to run the electrical system. The most important question is what is the payback ? Which way does the horsepower benefit you ? How much horsepower are you currently losing because of low electrical system voltage ?

[theremart]

RE: Alternator...

ok...

I think I was introducing some how TOO much load on the alternator at one time. If I could figure out how to downgrade the load to match the output to a fixed point, that matched the RV, plus a small load I think I would have something. ( see next post for HP calculation )

I think I will pull my wheel off my SSG with the wind generator and try it on the RV. I could then tune the alternator for a fixed point of voltage.

It is just now I have to be much much more careful about the balance of the magnets turning at 3200 RPM is a new ball game. Will enclose this in a box...

maybe I could embed the magnets into a wood wheel.... or cast a resin mold for the magnets...

Before I invest in a frequency generator, I believe I need to know who has built one, and how much more horsepower this will put out.

BTW I have pulled the hood off of my Air conditioner unit, I found tons of dust on the screen, getting this off alone will help tons on the cooling costs...

I hope to lubricate each of the motors in the AC unit and see if I can measure how much voltage is going to each.

Mart

[Chip Shorter]

It takes a few horsepower to run an alternator. Depending on the fla I would say 15-20 for a modern automotive say 130 amp alternator. I can get back with some real numbers for certain series alternators but generally thats the deal.

[Peter Lindemann]

Alternator Drag is Too Much

I did some research and i found that I needed a resistor in series with the coil.

Great info found here...
Using an Alternator in Renewable Energy Projects

The alternator seems to be TOO much for the rotoverter not enough torque when the coils are engaged.

Mart

Mart,

Yes, this is what I have been trying to tell people. When the current is restricted to the RV in the motor mode, the electric input goes down, BUT SO DOES THE MECHANICAL OUTPUT! A standard automobile alternator is NOT very efficient, and has significant drag from hysteresis even BEFORE producing any output current. (That is why they run so HOT in your car.) When these "real loads" are applied, the RV motor cannot respond to produce more torque, because its input current is limited by the capacitors and the reduced run voltage. The RV systems that are saving people money are designed to run a specific, fixed load, and the system is tuned to do that. It cannot respond to a variable load without being thrown out of its "operating window".

Peter

[theremart]

Frequency drive.

Ok has anyone ran an alternator before with the RV, if so what size?

Thanks Ash.

mart

[ashtweth]

Hi aadee and Mart


Okay, first of all that looping Schematic requires allot of tunning and empirical exploration , i have been researching, building and testing the RV for over 4 years and as a result of our open source engineers we have many practical energy saving circuits form it.

Two engineers in particular , Ed and Gene have spent allot of money trying to bring us some results based on that Sch, we are up too resonating the transformers and trying ti match impedances. (its not easy). Also Thanks to peter we have new ideas on how to extract the reactive power.

What you will have to do is READ ALL OF THIS COMPILATION, (4 years in the making) to see where we are up too.
http://panacea-bocaf.org/files/Advan...evelopment.pdf

Now, Mart, the RV will run that alternator if you adjust the voltage or Frequency, You need to get a frequency drive to give it more grunt. There are also RLC (which is what you need for looping) Ideas in the compilation mentioned.

Now the start caps vary for each motor, depending on what motor size you have a good rule of thumb is 120uf.thumb is 120uf.

[ashtweth]

Doh double post!

[aadee92]

are there any recommendations to the cap sizes for the schematic that WAS on "theverylastpageoftheinternet.com" They all have a "? mfd" would a 50 mfd work, 100mfd capacitors??

[theremart]

RE: alternator...

I did some research and i found that I needed a resistor in series with the coil.

Great info found here...
Using an Alternator in Renewable Energy Projects

The alternator seems to be TOO much for the rotoverter not enough torque when the coils are engaged.

Mart

[theremart]

RE: adding alternator to RV

Well it was spinning at 3200 RPM today, but I am unable to get it kick in...

I must be not doing something right on wiring it...

[ashtweth]

Aha, man a 15 year old is trying to loop an RV this is one cool day , i ma gonna show Hector this post, you know we really should also look into Eric Dollards/Peters recommendations as well.

[theremart]

RE: looping.

Tomorrow I will try to loop the RV... or at least set the stage for it.

I will put an car alternator on the end of the prime mover, and see if it can reach 2000 RPM... If it does it should be able to supply the power to the primary battery. After that replacing that with a capacitor bank should do the trick.

I have tested this on my 2 cycle generator, and it has enough power to run / start the RV. However the noise is a killer.

Need sleep now...

[aadee92]

Hello Everyone,

Ive been working on the rotoverter for several months, and entered it in my hometown science fair (i'm 15). It's been going pretty good, ive got 8 times more reactive power from the alternator than i have true power going into the Prime Mover. I heard that by using transformers you can extract or transform this reactive power to true power; but only 2 of the transformers came in, and as it is, i cant extract very much of this power, but i did melt a FWBR, that's encouraging. I'm trying to get this working to the extent of looping it before state science fair.

[theremart]

RE: capacitors

Mart, BE CAREFUL WITH YOUR CAPACITORS SWITCHES, MAKE SURE THEY HAVE A TOLERANCE OR YOU WILL GET ZAPPED(BEMF)

Good advice, they are rated at over 660 V Kone says that as long as they are over the rating I should be good.

Thanks for the advice.

[ashtweth]

Mart, BE CAREFUL WITH YOUR CAPACITORS SWITCHES, MAKE SURE THEY HAVE A TOLERANCE OR YOU WILL GET ZAPPED(BEMF)