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Kevin
Kevin, Licensed Electrical Contractor
Category: Electrical
Satisfied Customers: 3721
Experience:  30 years Licensed Electrical Contractor in Illinois, Adjunct College Electrical Instructor, Former Electrical Inspector, Diploma: Digital Electronics, FCC Technician License
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HOW DOES A WIND MILL OPERATE: EXAMPLE: A 1MW WIND MILL IS

Customer Question

HOW DOES A WIND MILL OPERATE :
EXAMPLE : A 1MW WIND MILL IS CONNECTED TO THE GRID WHICH IS INFINITE, SO THE MOMENT YOU CONNECT THE WIND MILL TO THE EB LINE IT SHOULD SEIZE (STOP) IMMEDIATELY. AND HOW IS THE 50 CYCLES (HZ) MAINTAINED THROUGHOUT IN WINDY AND LESS WINDY SITUATIONS
Submitted: 1 year ago.
Category: Electrical
Expert:  Kevin replied 1 year ago.

Hello and welcome to Just Answer. My name is ***** ***** I will be happy to assist you with your electrical question.

1) Not sure what you mean that when the wind generator is connected that it will seize?

2) Wind generator permanent magnet motors are designed as either 50 or 60 Htz when back-fed and grid tied to the local electrical utility. The motor is internally designed for the frequency...........ie.... 50 Htz in your example. Globally, motors are designed and manufactured as either 50 or 60 Htz. An AC inverter is also designed for either a 50 or 60 Htz output.

In India, your public utility grid is designed to operate at 230 volts @ 50 Htz.

3) Less wind conditions = less amperage output from the generator motor. Thus less power is produced.

More wind conditions = higher amperage output from the generator motor. Thus more power is produced.

4) Wind turbine blades are connected to a permanent magnet DC voltage motor. When the wind spins the turbine blades, the motor shaft cranks out DC voltage. The DC voltage is then sent to a Charge Controller device which regulates the maximum amount of DC voltage. The DC voltage is then fed into a battery bank to store the voltage. An inverter is connected to a battery bank which converts the DC voltage to AC voltage (230 volts) which is either consumed and/or grid tied to the local electrical utility. In summary, a wind energy source is converting mechanical energy to electrical energy by the wind rotation of the turbine blades, spinning a motor and out putting a DC voltage and converting it to AC voltage and then grid tied to the public utility grid via a circuit breaker installed in your main electrical panel.

If you have any additional questions, just let me know and I’ll be glad to answer them for you.

Otherwise, don’t forget to rate me before you log Off.

Thanks..............Kevin:)

Customer: replied 1 year ago.
SORRY I DIDNT UNDERSTAND
1. AS FAR AS I KNOW ONLY WHEN A GENERATOR IS CONNECTED TO LOAD IT DELIVERS CURRENT .
2. IF THE WIND MILL SPINS SLOWLY THEN THE HZ SHOULD ALSO GO LESS
3. AS WE SEE IN A GENERATOR IF IT IS OVER LOADED WITH LOAD, IT STRUGGLES AND TURNS OFF
Expert:  Kevin replied 1 year ago.

1) Yes of course the generator size and wind speed and the load must all be proportional and the components (turbine blade pitch, controller, shaft, yaw drive, gear box, brake, motor type, etc.) must be properly designed, that's a given.

2) The inverter has a fixed frequency....... in your application it needs to be a 50 Htz frequency since your electrical grid and your loads are 50 Htz. The inverter frequency does not change. Don't get confused on the rotational speed of the turbine that is impacted by the wind speed. Frequency has nothing to do with the wind speed. The generator motor and the inverter are the 2 components that control the fixed frequency outputs. Both of these components must match each others frequency.

3) If the wind is less mph, then the turbine amp output is less and can thus support a smaller load. The generator and/or inverter frequency of 50 Htz each remains as constant.

4) If the wind is more mph, then the turbine amp output is greater and can thus support a higher load. The generator and/or inverter frequency of 50 Htz each remains as constant.

I hope this better explains that the turbine and/or inverter frequency has nothing to do with the rotational wind speed frequency. You are comparing apples to oranges...ie....... 2 different things:)

Whether the wind speed is 5 mph or 25 mph, the turbine and/or inverter are both generating voltage at a 50 Htz frequency.

The rotation of the turbine blades is called wind speed rated in mph and is not rated in frequency. The magnetic fields in both the generator motor and/or inverted are rated in frequency.

If you have any additional questions, just let me know and I’ll be glad to answer them for you.

Otherwise, don’t forget to rate me before you log Off.

Thanks..............Kevin:)

Customer: replied 1 year ago.
kevin
please see some wind mill working videos on youtube , where in they say a planetary gearbox is placed in between the blade shaft and generator. this gearbox is used to increase the rotation upto 90 times to attain a frequency of 50 Hz.
if you say there is no connection between the rotation speed of the blades and frequency then why an planetary gearbox which steps up the rotation speed to 50 rounds per second..
i hope you are advising me properly.. i dont know what apples and oranges have to do with a wind mill.. i have spent money, hoping i ll get my doubt totally cleared .. please lets not joke about
Expert:  Kevin replied 1 year ago.

1) I don't provide jokes. I provide correct answers:)

2) I've been a licensed electrician for 29 years, a college electrical instructor for 5 years as well as a former electrical inspector. I am also certified on wind and PV power applications. I take my job and customer questions and/or electrical projects very seriously.

3) Apples & oranges is a slang term where someone is comparing 2 different things. In other words, wind speed of the turbine is not to be compared to the generator and/or inverter output frequency. Wind speed and component (motor and inverter) frequency are 2 different entities. Thus the slang term is used to compare apples & oranges:)

4) As I previously mentioned, the wind speed can be low (5 mph) or higher (25 mph)and the output voltage frequency on the components is still 50 Htz.

5) If the turbine is spinning at a 5mph wind speed or if it spinning at a 25 mph wind speed, the end result is that both are cranking out voltage at 50 cycles per second.

6) It is a well known fact that wind turbines can generate electricity as low as 5 mph and they can be grid tied to your 50 Htz system. If the wind speed is as low as 5 mph, then you explain to me as to how a turbine which is has internal motor windings and coils that are manufactured to a 50 Htz frequency which can produce a lower frequency (less than 50 Htz), yet still be connected to a grid that requires 50 Htz? It is impossible to modify the output frequency of a motor and/or inverter unless you change the internal winding/coil.

7) The most important part of this discussion and that you are not understanding is that frequency is part of the internal design of any motor, generator and/or inverter. Frequency is not wind speed and wind speed is not frequency. Frequency is derived from the internal magnetic windings/coil of a motor and not from the wind speed. I don't know how to explain this any better than I have?

8) Simply put, if you purchase a wind turbine and/or an inverter that is meant to be deployed in India as well as most other portions of Asia and Europe, the output voltage frequency will be 50 Htz. If you purchase the same products here in the United States, both components will be @ 60 Htz since our grid is different than yours as we are on 60 cycles per second and not 50 cycles.

Customer: replied 1 year ago.
then why is the planetary gear box installed in a wind mill,there must be some reason
Expert:  Kevin replied 1 year ago.

1) To stabilize or equalize the wind shear load on the turbine shaft and to prevent damage to it and/or the shaft bearings. Also used to maintain a minimal noise level from the shaft rotation. Some manufacturers call the device a gear box, others call it a controller........ie... same concept just a different name.

Customer: replied 1 year ago.
A gearbox is typically used in a wind turbine to increase rotational speed from a low-speed rotor to a higher speed electrical generator. A common ratio is about 90:1, with a rate 16.7 rpm input from the rotor to 1,500 rpm output for the generator. Some multimegawatt wind turbines have dispensed with a gearbox. In these so-called direct-drive machines, the generator rotor turns at the same speed as the turbine rotor. This requires a large and expensive generator. Other wind turbines on the market sit in-between, with gearbox ratios of about 30:1, dispensing with the highest speed stage in a typical gearbox. There is a trade-off between the reliability of gearboxes and gear stages and the cost of slower, higher torque generators.
AND GOES ON..
http://www.windpowerengineering.com/design/mechanical/gearboxes/gears-gearboxes-101/
NOT THIS ONLY BUT THERE ARE MANY MANY MORE SITES THAT SAY THE SAME
I AM SORRY I HAVENT SEEN ANY SITE THAT SAYS WHAT YOU SAY
THANKYOU
Expert:  Kevin replied 1 year ago.

Gearboxes, wind generator (magnetic motor) and inverters are all inter-active components of a wind system.

Your question is about how the output frequency changes due to the wind speed.

Simply put, if the wind system is grid tied, the inverter output design is what creates the required 50 Htz cycle back to the utility grid. On a properly functioning inverter, the output frequency never changes no matter the wind conditions....ie........ the inverter always maintains a consistent 50 Htz output frequency.

There can be (0) zero mph wind speed and if the wind system is connected to a battery bank and to a 50 Htz inverter, the output voltage that is being back-fed to the grid is being produced at a 230 volt AC voltage 50 Htz frequency. Thus the gearbox or controller does not constitute the voltage output frequency, the inverter is the final electrical component that is responsible for frequency.