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Power-User

Join Date: Apr 2007
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Roto Phase As Generator To Create off Grid Power

12/26/2008 5:15 PM

We have a client that ask us if we will use his 3 phase converter , a roto phase converter, to be his off grid alternating power source and I need instructions as to how to do it properly. What They Want Is 230 single phase service at their 2 200 amp 40 switch panels and they can not afford to get the grid brought to them to feed the double 200 amp service panels ; so they want us to use what they have on hand plus a battery charger & Inverter for the batteries to create a storage system they can depend upon.

Looks like it should work on the surface so:

Would there be an an Electrical Engineer, here about CR4 that Would tell me how to do this properly please ? Going to have a Electrician to wire it together , I have one on the payroll. What size IE engine should drive it ? They have proposed a Good Running Ford Ranger Pick up truck as the drive motor Come off the drive shaft with a belt pulley and drive the Roto-phase ( So Lots Of Potential 4 Cyl HP ) which would also give them, (CH&P) , hot water to store, when power is being generated. It is a gasoline engine ( cheap to fix, & Lots of them around ) , so at what RPM should this thing run, to produce 60 hertz power ( 1800 Plus 10% )? Are Any Capacitors ( & how Many ) or other devices required in the line, before line connection to mains to create as close to Sine Wave As Possible ? And What Else Do We Need, Etc ?

The info on his Rotary Phase Converter Is As Follows:

Model RPC 10-30

Largest Motor HP 10

Volts 230

HZ 60

Combined Total HP 30

Amps NL. 10.0

Thank You Very Much For Any Help You Can Be !

Joe Woodall

Georgia Adobe

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#1

Re: Roto Phase As Generator To Create off Grid Power

12/26/2008 6:04 PM

I would suggest you do a Google search for Roto Phase Converter. There were a number of hits. Contact the Mfg for assistance.

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#2

Re: Roto Phase As Generator To Create off Grid Power

12/26/2008 6:05 PM

You can't use a rotophase for that purpose. A rotophase takes 1 phase power and uses a capacitor plus the motor rotating field to create a pseudo 3rd phase. But it is not a generator/alternator all by itself. At best, the 3 phase motor inside of the rotophase could be theoretically made into a 3 phase alternator, but that is really a difficult project for a novice. The problem is, a 3 phase motor cannot "self excite" to become an alternator, it needs to be connected to a source of excitation power, and that is usually the grid itself. There are tricks to using capacitors and residual magnetism inside of the motor frame to allow self excitation, but that is where the tricky part comes in. You can waste a lot of time and money trying to do it and get nothing for it if you don't know what you are doing. There are articles available on the web in some of the Alt Power forums if you search. They can give you some insight as to the possibility. But to be quite hnest, the practicality of doing that for 2 x 200A services is way beyond what most people would want to tackle.

You are better off buying a true AC synchronous alternator that can be excited from an expernal DC source such as batteries in order to begin generating power. Speed regulation on an auto angine is anther issue needing a lot of attention, but that is not something I know much about. I justknow it's difficult. When you see people use car engines for generation, they typically use DC generators because speed regulation isn't as critical. Then you can hook up an inverter to give you AC power.

You seem to be a novice, so my advice is to start with reading up on off-grid power systems, especially the parts about sizing and capacity. You cannot just say "...230 single phase service at their 2 200 amp 40 switch panels" and have that mean anything useful. You must first do a very thorough and careful load assessment, along with some serious sould searching on your client's part as to which loads he really needs. Running a gas powered car engine to spin an alternator is an extremely expensive endeavour in the long run.

Good luck with that.

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#3

Re: Roto Phase As Generator To Create off Grid Power

12/26/2008 11:43 PM

Hi GA ,

That's A Pretty Cool Idea To Try & Recycle Things, That Your Customer All Ready Has Since It Might Save Them Money.

As It Is, A Fairly Big One, If You Can Excite The Those Windings, It Might Even Run A Good Sized Motor Too, As Your Notes Say It Runs In Normal Mode, A 10 HP Motor. Perhaps, A Set Of Capacitors & A Battery Might Drive That Thing, In Normal Mode, Without Using The ICE At All And Then This Might Give You, 180 Volts AC That Could Be Used To Charge The Battery & Deliver 120+ AC Volts Back To The Panel ,In Addition. No Such Thing, As Free Energy - But This Bears Doing Just To Find Out, How It Would Play Out & As I Have 1 Of Those Old Roto-Phases Myself, Too.

If Not, Maybe They Will Buy One Of Your Big Generator Heads From Over At Your Web Site, Or You Could Give Them A Fair Trade In Value , For Their Roto-Phase , On One ?

Cheers,

Bond

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#4

Re: Roto Phase As Generator To Create off Grid Power

12/28/2008 8:45 AM

Its not that I want to throw cold water on a hot fire but what you are trying to do is not that simple, and will wind up spending more time on something that probably won't work. Unless you spend more money than you want to and only then would you find you have a system impossible to maintain and expensive to fix.

First observation:

You were on the right track when you were asking what the engine rpm should be. You are going to need a governor to apply power. Since this is a "one off" design you are probably going to have to have someone design or monkey up a make shift one. Since it is one of a kind it is not going to work right the first time, and it may or may not ever work in a pratical situation.

Second observation:

On site fossil fuel type generators are always more expensive to operate per KWH than practically any other source of power.

Third observation:

How are you going to transfer the power?

In conclusion, many people have great ideas and sometimes there is new technology developed that may make that idea work out. But normally, if there are any good cheap ideas that gererate power. Someone has already slapped a patent on it and is making themselves a good living off of it.

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Anonymous Poster
#5

Re: Roto Phase As Generator To Create off Grid Power

12/28/2008 2:33 PM

Hello,

Can you change their rotor into a Permant Magnet type rotor, so as to excite the windings when it is turned by their motor ?

That way its just like a generator; Just a thought.

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#6

Re: Roto Phase As Generator To Create off Grid Power

12/28/2008 7:54 PM

I recently purchased an R5 to power some equipment in our plant. We have been using the smaller R3 forever and since I know very little about these matters I sought tech advise. I contacted Roto-Phase and they were very knowledgeable and helpful.

I would recommend them without hesitation.

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Power-User

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#7

Re: Roto Phase As Generator To Create off Grid Power

12/30/2008 12:11 AM

Hello Everybody,

I have not thought much about this, since posting the question, with Christmas & Everything but, I'm thankful, to you all , for the input , received .

I made a request of the M.P. at Roto-Phase.com to comment if he had the time, as they would (as pointed out) surely know more about this. I think too, if I were to attempt my clients request and work on this , I will be inclined to ask the actual equip mfg.'s tech guys, for their input too , ( bet somebody there, has done something on that idea before ). Also, Not being a expert at all but , I've never looked at a schematic of this device but, if it has a "X" number of stator coils and it has "X" number of magnets turning, they have to be proportional to each other ,so as to generate the proper current flows. Thus, if a rotor is to be changed, then a custom one, would have to be turned down to size, at our fabrication shop, to try that idea . No way, a 6 pole stator and a 4 pole rotor will work together; so, all the proper magnet sizing and their spacing is required if there is room in there. The bigger the need, the bigger the unit gets built, for its properly designed purpose.

Yes, I'm still going to try to sell them something else though, as their prime mover set up, We've Got Plenty Of Equipment Ready To Install & after all I can Buy,Sell , Finance & Install easier, than I can create - any day. Plus, we are receiving in some really cheap offers from China , on good PMA alternator Equipment, (I guess the economy is changing the price lines, there too) .

Would have loved to come back and see a good plan though, to use their present equipment and save the client some money - As They Need It & it's kind of been 1 goal, that we always worked towards, for each client, during our 2 years in business so far.

All The Best New Years Wishes & Many Thanks From :

Joe Woodall, Managing Partner

Georgia Adobe Rammed Earth & Renewable Energy

Dewy Rose , Georgia 30634 CSA

706-213-7693

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#8

About Solar Panels and System

07/24/2009 7:40 AM

See this Solar Panels and System. Hardy Solar Home Stezader 4 kW off grid energy generator system.1,500 Watt off grid Solar Panel System.

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