It is known that electric machines have the principle of reversibility. It is quite possible to make a generator from an old electric motor and use it for your household needs. This article talks about how an old asynchronous motor and an industrial walk-behind tractor, with skillful hands, are transformed into a free supplier of electrical energy.
To generate electric current, an old Soviet asynchronous electric motor “AOL 32-4” is used. This unit was produced back in the 50s of the last century. But it turned out to be functional even 70 years after leaving the factory assembly line.
The gasoline engine of the walk-behind tractor will rotate the electric motor shaft.
The ratio of the pulley sizes on the motor shafts is approximately 1:1.
To use an electric motor as a generator, important electrical characteristics must be taken into account:
- winding wire cross-section;
- maximum engine speed;
- Efficiency and cos are important for selecting capacitors;
- winding connection diagram.
All this information can be found on the enclosure plate or on the Internet.
DIY 220 V generator from a walk-behind tractor
The electric motor in our homemade generator is connected in a star circuit.The middle common point of the windings is the neutral wire. And the phases are removed from the rays of the star. A capacitor with a capacity of 170 μF is connected between the two beams. Energy can be taken from all rays - both where the capacitor is powered and where it is not. The phase from each beam is output to a separate socket.
From each outlet you can take approximately 800 - 900 watts of power. Accurate measurements were not taken. An 1800 W grinder with a cutting wheel was connected. Iron cuts easily. The current consumption was measured with an ammeter. Amounted to 4 Amperes from one phase. An experiment was also conducted with a 750 W drill. An attempt to stop the rotation by resting the cartridge against the board was unsuccessful. Yes, the voltage dropped to 200 Volts, and the current was 3 Amperes.
The voltage between the rays of the “star” was also measured. Amounted to 380 - 400 Volts. However, single-phase transformer inverter welding did not work.
Let's start testing. We start the walk-behind tractor. To control the electrical parameters of the network it is used digital device. Three parameters are displayed: voltage, current, frequency. At idle speed of the walk-behind tractor indicator shows a voltage of 125 Volts and a frequency of 36 Hz. Not enough, but the electric drill is already working. We increase the speed of the walk-behind tractor - voltage 245 V, frequency 48 Hz. The drill started working more happily. Current consumption is 1.6 Amperes. When the grinder is operating, the voltage drops to 190 Volts, the current consumption increased to 2.9 Amperes.
And now about the main drawback of the design: the high fuel consumption of the walk-behind tractor. If, for example, there is no load on a purchased generator, then it operates in economical mode and consumes almost no fuel. The walk-behind tractor is quite power hungry. There is no economic gain due to this.You can use such a homemade structure for one-time work, to cut or drill something 100 - 150 meters from the garden.
But the generator is operational, and there is no limit to perfection - we will bring it to perfection, adjust it, and modernize it.
