# Electrical If i wanted to make a generator ... which equations would I need to use?

#### Roxy Hasan

i want to make a generator by rotating turbine by water... i want a equation for speed of the armeture and others plz help

#### jrmichler

Google is your friend. Good search terms to get started are small hydro generator. Since you are studying to be a civil engineer, a project like this is definitely in your specialty.

#### fresh_42

Mentor
2018 Award
i want to make a generator by rotating turbine by water... i want a equation for speed of the armeture and others plz help

Could you be more specific? An equation is probably one of the last things you need to consider.

#### anorlunda

Mentor
Gold Member
If you want to make a hydro power project, the place to start is with your water resources. You need a flow of water running down a vertical distance.

How much water flow (liters per hour) do you have?
How much vertical distance (meters) does the water fall?

#### Roxy Hasan

i will model the tank for the project.. i will make the minimum pressure needed for that power .. but for that i need to know first how much water head pressure i need to create.. so i wanted yours help for the dianamo equation.. from which i can measure the rotating speed which is releted to the water flow.. i need to create at leadt 2 hp power from the dianamo .. plz help me

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#### Roxy Hasan

If you want to make a hydro power project, the place to start is with your water resources. You need a flow of water running down a vertical distance.

How much water flow (liters per hour) do you have?
How much vertical distance (meters) does the water fall?
Google is your friend. Good search terms to get started are small hydro generator. Since you are studying to be a civil engineer, a project like this is definitely in your specialty.
thnx .. but i can't find any suitable or understanding equation from there.. there is all projects and so on.. but I can't find the right formula or way to apply it

#### Roxy Hasan

i got the equation E= B*v*I .. but i can't understand it good way.. do i need to calculate the I as the full Length of wire ..

is this equation is also applicable for ac current or only dc..

#### anorlunda

Mentor
Gold Member
If you really want to build it, you must start with the numbers for the water, not for the electricity.

#### Roxy Hasan

If you really want to build it, you must start with the numbers for the water, not for the electricity.
i know but i i want to creare a project for exibithion.. where i will need to work a 2Hp water pump ... i want to work on structure of water way so i need to know the speed of water then i can make the structure of water way..

#### Roxy Hasan

here main fact is free eatwa not electricity

#### anorlunda

Mentor
Gold Member
i know but i i want to creare a project for exibithion.. where i will need to work a 2Hp water pump ... i want to work on structure of water way so i need to know the speed of water then i can make the structure of water way..
OK, that is more clear now. You want to learn about generator design. AC or DC, whichever is easiest

Must you build it from iron and wire, or can you use pays like an alternator from an automobile?

I don't understand "eatwa"

Ping @jim hardy

#### Roxy Hasan

sorry .. spelling mistake not eatwa .. it is water ..

thnx ... for advising alternator... but i also need to know the equation for it..

#### Roxy Hasan

how can i easily calculation from alternator... it is more complex... i used iron and wire for less complexibity...

#### jim hardy

Gold Member
2018 Award
A question well stated is half answered.
i want a equation for speed of the armeture
i need to create at leadt 2 hp power from the dianamo

Here is a primer on motors. It introduces the concepts of torque and power which will be fundamental to your design effort.
http://www.aspenmotiontech.com/docs/brushless-dc-motor-primer.pdf
It also touches on electromagnetics.

I think your starting point will be here:
horsepower = 2pi X torqueft-lbs X rom / 33,000
so your speed depends on the turbine with which you intend to drive your generator.
You'll have to pick a turbine size and speed from the volume and velocity of water that you have available at your turbine.

Here's a primer on hydraulic power of a pump. A turbine will be similar.

https://www.thermexcel.com/english/ressourc/pumps.htm

that should give you basic vocabulary.
Here's another primer on pump design.
www.psaincorporated.com/files/Pump_Basics.ppt
a turbine is basically a pump with flow reversed.

Then look for a dynamo that'll do what you want.

To design a dynamo from scratch you'll have to become familiar with magnetic unts .

Energy is conserved. So you'll have to extract at least 2hp from your water source.
2hp will move a LOT of water , so you're looking at a sizeable machine.
Go to the hardware store and look at a 2hp yard sprinkler pump.

An automobile torque converter has a turbine in it.
"Home Shop Machinist" magazine a few years back featured steam turbines made from them.
I suppose they'd work with water but i've never seen it done....would be an interesting project

I think you've bitten off a lot for a beginner.
You might look into a simple overthrow water wheel and car alternator driven with bicycle chain.

good luck. .

old jim

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#### Roxy Hasan

A question well stated is half answered.

thnx very very much.... i needed just these things for my projects... i really wanted this equation and the types of information you just provide...

Here is a primer on motors. It introduces the concepts of torque and power which will be fundamental to your design effort.
http://www.aspenmotiontech.com/docs/brushless-dc-motor-primer.pdf
It also touches on electromagnetics.

I think your starting point will be here:
horsepower = 2pi X torqueft-lbs X rom / 33,000
so your speed depends on the turbine with which you intend to drive your generator.
You'll have to pick a turbine size and speed from the volume and velocity of water that you have available at your turbine.

Here's a primer on hydraulic power of a pump. A turbine will be similar.

https://www.thermexcel.com/english/ressourc/pumps.htm
View attachment 229868

that should give you basic vocabulary.
Here's another primer on pump design.
www.psaincorporated.com/files/Pump_Basics.ppt
a turbine is basically a pump with flow reversed.

Then look for a dynamo that'll do what you want.

To design a dynamo from scratch you'll have to become familiar with magnetic unts .

Energy is conserved. So you'll have to extract at least 2hp from your water source.
2hp will move a LOT of water , so you're looking at a sizeable machine.
Go to the hardware store and look at a 2hp yard sprinkler pump.

View attachment 229867

An automobile torque converter has a turbine in it.
"Home Shop Machinist" magazine a few years back featured steam turbines made from them.
I suppose they'd work with water but i've never seen it done....would be an interesting project

I think you've bitten off a lot for a beginner.
You might look into a simple overthrow water wheel and car alternator driven with bicycle chain.

good luck. .

old jim

#### Roxy Hasan

I dont need to create it.. just proved it with my talk and presentation .. a small protype will be need .. which i can easily make from my place...

#### jim hardy

Gold Member
2018 Award
Ahh a Powerpoint turbine ! There are lots of primers out there google found several.

There is an active business in small low head hydro generators for off-gridders .

Try a search, you can get an idea what people are doing out there.

"If i wanted to make a generator ... which equations would I need to use?"

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