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I have been told that a wind operated generator can be made using an electric motor by turning the shaft by wind power and drawing off generated current through the original current input terminals.
Is this right?
What voltage would be generated?
BOSSCHESTER
Is this right?
What voltage would be generated?
BOSSCHESTER
Answers
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It depends upon the speed of rotation of the shaft. Let's assume that it's a 12V motor. If you remove the electrical power source but then get the shaft to rotate at the same speed as it would when 12V is applied, you'll generate (roughly) 12V. If you only get the shaft to rotate at half of it's 'normal' speed, you'll generate (roughly) 6V.
However, the basic principle is correct. A generator is simply a motor working in reverse.
Chris
However, the basic principle is correct. A generator is simply a motor working in reverse.
Chris
It depends on the type of motor. Technically any kind of motor can be a generator and vice versa. Some are more easily made to work the other way.
The old brush type generators used in cars until the early sixties made excellent DC motors. I uses them to drive workshop tools directly from the house battery.
These require a field to be switched on to generate. Quite a bit of power is used in the field magnets. Varying the field current changes the torque and operating speed of the generator depending on the prime mover employed.
Permanent magnet motors make great generators. No field to energise. However the load they place on the generator is more difficult to contol.
Wind turbines have a preferred operating speed that more or less linearly rises with the wind speed. The torque they produce rises at the square of the wind velocity. The load absorbed by the generator must be matched to the availbel torque of the turbine or efficiency will be poor or the turbine may stall.
The best generators for small wind turbines are the permanent magnet multipole flat motors used in Fisher & Paykel washing machines. They have a stainless steel shaft and can be run without a stepup gear stage.
Their many poles and a useful potential to change the winding configuration.
Being 3 phase they already have a simple star-delta 1.8 :1 ratio by changing phase connections. The pole windings can also be rearranged to parallel connections for higher current at lower voltages.
With so many combinations most turbines can be roughly matched to the voltage of the battery. Better matching can be achieved by complex electronic controls. All that is required is a three phase bridge rectifier which are readily available.
Permanent magenet generators tend to be "notchy" which can make them difficult t so start.
The old brush type generators used in cars until the early sixties made excellent DC motors. I uses them to drive workshop tools directly from the house battery.
These require a field to be switched on to generate. Quite a bit of power is used in the field magnets. Varying the field current changes the torque and operating speed of the generator depending on the prime mover employed.
Permanent magnet motors make great generators. No field to energise. However the load they place on the generator is more difficult to contol.
Wind turbines have a preferred operating speed that more or less linearly rises with the wind speed. The torque they produce rises at the square of the wind velocity. The load absorbed by the generator must be matched to the availbel torque of the turbine or efficiency will be poor or the turbine may stall.
The best generators for small wind turbines are the permanent magnet multipole flat motors used in Fisher & Paykel washing machines. They have a stainless steel shaft and can be run without a stepup gear stage.
Their many poles and a useful potential to change the winding configuration.
Being 3 phase they already have a simple star-delta 1.8 :1 ratio by changing phase connections. The pole windings can also be rearranged to parallel connections for higher current at lower voltages.
With so many combinations most turbines can be roughly matched to the voltage of the battery. Better matching can be achieved by complex electronic controls. All that is required is a three phase bridge rectifier which are readily available.
Permanent magenet generators tend to be "notchy" which can make them difficult t so start.
Ordinary induction motors can aslo be generators. Turning one faster than its inherant speed and it will generate back into the supply. When fitted with suitable capacitors they self excite and can generate very high voltages. The three phase units make very robust generators.
The wind turbine I built uses a three phase induction motor as a generator. A specially designed transformer keeps the load matched for the turbine as the frequency changes.
The system is largely passive with the intrinsic properties of the generator and transformer matched. An electronic controller forces the tubine to stall when it reaches a preset speed or the battery is fully charged.
The wind turbine I built uses a three phase induction motor as a generator. A specially designed transformer keeps the load matched for the turbine as the frequency changes.
The system is largely passive with the intrinsic properties of the generator and transformer matched. An electronic controller forces the tubine to stall when it reaches a preset speed or the battery is fully charged.
Many thanks to you guys who have clearly gone to a lot of trouble and time expenditure to reply.
I have two motors. One is a pretty hefty rotivator motor - I believe the old type with brushes. The other is a magnetic water pump motor. They both operate on 230v. How would I store the current?
I do wish that I had paid more attention in Physics at school - but that was more than 60 years ago and the old memory ain't what it used to be!.
George.
I have two motors. One is a pretty hefty rotivator motor - I believe the old type with brushes. The other is a magnetic water pump motor. They both operate on 230v. How would I store the current?
I do wish that I had paid more attention in Physics at school - but that was more than 60 years ago and the old memory ain't what it used to be!.
George.
The answer to your second question is using batteries. These store energy but have the disadvantage that they provide a DC voltage - and at relatively modest voltage levels per unit battery (say 12V, as from a standard lead-acid battery).
It really depends on what you are trying to do with this wind generator. One wonders if it is merely experimental, or whether you are hoping to save money. Unfortunately a domestic size of generator only produces about 500W of power when the wind is blowing at a reasonable rate. A DIY perhaps might produce rather less.
It would be possible to rectify the output from an AC supply and store it in banks of batteries - normally done with banks of batteries in series so producing 12V output. But then if you want to use this stored energy back into your domestic lighting circuits, you need an inverter to turn 12V DC back to 240V AC, using a qualified electrician to do it for you. Developments are being made all the time on battery technology - particularly for use in motive power for auto technology.
It really depends on what you are trying to do with this wind generator. One wonders if it is merely experimental, or whether you are hoping to save money. Unfortunately a domestic size of generator only produces about 500W of power when the wind is blowing at a reasonable rate. A DIY perhaps might produce rather less.
It would be possible to rectify the output from an AC supply and store it in banks of batteries - normally done with banks of batteries in series so producing 12V output. But then if you want to use this stored energy back into your domestic lighting circuits, you need an inverter to turn 12V DC back to 240V AC, using a qualified electrician to do it for you. Developments are being made all the time on battery technology - particularly for use in motive power for auto technology.
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