Sizing Induction Motors and Cogen to Lower Power Bills

You will not be able to use that induction motor as power generator.

You need a real generator.

Take a look a the web pages from different windmill suppliers.

You will need a rectifier and inverter to couple the power from your windmill mounted generator to the grid.

When your bill is that high due the welding you will not be able to reduce a lot of the power bill. Your electricity meter will not turn back (but you will be feeding electricity to the grid) You will need a second or special meter that counts the kWh that you deliver to the grid, and you will be paid little money for it.

A possible route to look at is the use of a battery pack that you feed with the windmill and that you can use to weld. I don't know the real technique behind it but for every problem there is a solution.

As generator you can use a car/truck alternator.

Thanks for the comment Gwen, but I am still lost.

If the induction motor/generator is excited from the grid then I should not need the rectifier and inverter to couple the power. It wiil then be in sync with the grid. All I should need are some relays to cut in when up to speed and cut out for overspeed of the gen. Maybe I am not understanding this correctly.

As for payment from the power company, I am not looking to make any monies. I do hope to offset my bill by building credits through net metering during times of no welding work. If there is any excess credits at the end of the period, although I doubt there will be, they are welcome to them.

Asynchro AC motor could be a good generator if Mechanical Source of Energy (Wind) could deliver the speed over its rated value. Most of the time it requires a motor with very low rated speed or speed reducer! Before you decide what unit to select check out the speed of the shaft in real!

Check out this website.

http://www.thebackshed.com/windmill/default.asp

There is an article on converting induction motors (although an ambitious one). It would be easier to find a surplus DC treadmill motor.

Let us review what you stated. By the way, you DONOT generate 3>5 Kw per day.

• You hope to generate 3 to 5 KW. Say Average 4KW. In 24 Hours you ought to generate 96(24 hrsx4)KW-Hrs(if you store at 100% efficiency). Or in a month you can store for your own use~ 2900 KW-Hrs. Do you Storeyet?
• You do a lot of welding. Please tell us how you weld-MMA-TIG-Mig/Mag-SAW - which? Are you the only welder in your shop? Do you actually weld say 3 hours a day--5 days a week?
• What machine do you ? What welding current?What normal KVA/KW do you use -when you actually weld?
• Would you be happy to be self-sufficient by generating all the power you consume?
• Is your Wind generator already operating and gives you 3>5 KW?
• If you answer all my above correctly and completely--I have solutions for you.
• Waiting to hear from you.

1. I have no desire to store any. Except possibly in the form of credit through net metering from the power company.
2. As for the welding, I use a buzz box and MIG/TIG welder, 8 to 10 hrs shop time two days a week. that probably relates 4 to 6 hrs continuous weld time (power on)
3. I will check the KVA in the daylight. Currently to dark.
4. No major machines except small grinders, compressors, drill press, sander, chop saw, band saw, etc.
5. Yes I would be happy to generate all the power I consume ( who wouldn't )
6. I have not yet erected the mill. I plan to do so when the weather warms to at least 40⁰ F. As of now it is currently -8⁰ F

Also, I will have help in the spring of the year, I am somewhat physically challanged as a disabled firefighter and do not get out much in the snow.

Disability - Crushed Spine

Did you check with the local electricity company on the possibility to push electricity to the grid? What do they pay you?

Every system that you will install will be effective, the only question is at which cost?

You could estimate the power generated by a windmill over the year and try to come to a financial break even. When you install the tower yourself it will be sooner than a complete commercial installation.

You could also check what gives you the best payback: selling electricity or using the generated electricity to heat your shop and house. (through a heating element in a boiler that feeds the central heating system)

You seam to be handy with tools available, there are nice explications on the net explaining how to build a decent windmill. A nice one is the Lenz turbine. Rather easy to build, Those vertical types can be coupled to drive one generator and don't need to be aligned to the wind.

The generator part is somehow more difficult: an asynchronous motor can't be used as a generator like that, you need to have a magnetic field from the rotor that goes round while it turns. An asynchronous generator is something completely different than a motor. It is a very special machine, check it out on wikipedia. Efficacy is lower than a normal generator. Although it is used in medium size windmills as they can be directly coupled to the grid (no need for an inverter) and don't need a gearbox.

Buying your generator is probably the best choice, building this kind of machines is specialists work. When you want at least some decent efficacy.

Thanks for the encouragement Gwen

Here In Michigan the power company will not by any power pushed into the grid. They will only credit for the excess, unless I become a commercial generator at 50KW/230V per hour. They call it net metering.

As for the towers, I have four at 20 meters. Left over from when the power company moved a primary feed line.

I do like the Lenz turbine setup. We have a steady supply of wind at low speed, but rather finickey as it seems to come from all directions at the same time.

If you can send me a contact Telephone number I would like to fax you my email address. I prefer to do it this way to stop spam rather than post address here.

Hi,

Use the private mail section of your account, you can send private mails to everyone.

The mail stays within the CR4 system but only you and the addressee can see it.

This advice is also for all the rest, interested to contact someone: do it this way.

Gwen