HACKED! : Turning an Induction Motor into a Generator!
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Date: 2020-09-06
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Comments and reviews: 9
Power
Ya know, all you had to do to use this as a generator is to spin the shaft faster than synchronous speed while connected to mains. This does assume you have 3 phase power. You can also use an induction motor as a brake (energy lost in the motor) by applying a small DC voltage and current, as this creates really strong eddy-currents. It does heat up the rotor a lot and can damage it if your not careful, though.
Some of the more fancy ESCs or VFDs meant for powering induction motors have this feature built in. They can brake the motor to slow it down rapidly in CNC applications, and effectively regen. Tesla obviously does the same, regen with an induction motor.
Honestly the working principle of induction motors is just black magic to me. Field Oriented Control with a PMSM or BLDC makes perfect sense. Just a rotating B field causing magnets to chase it. But the rotor power being induced by the stator just makes them so much more complex!
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Ya know, all you had to do to use this as a generator is to spin the shaft faster than synchronous speed while connected to mains. This does assume you have 3 phase power. You can also use an induction motor as a brake (energy lost in the motor) by applying a small DC voltage and current, as this creates really strong eddy-currents. It does heat up the rotor a lot and can damage it if your not careful, though.
Some of the more fancy ESCs or VFDs meant for powering induction motors have this feature built in. They can brake the motor to slow it down rapidly in CNC applications, and effectively regen. Tesla obviously does the same, regen with an induction motor.
Honestly the working principle of induction motors is just black magic to me. Field Oriented Control with a PMSM or BLDC makes perfect sense. Just a rotating B field causing magnets to chase it. But the rotor power being induced by the stator just makes them so much more complex!
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Maulik
Eddy currents works both ways, in stator and winding, get the clue!
It will likely kill off any induction in wires and induction with those tiny magnets is very small comapre to surface area winding has.
Not to mention, coils in these motors are used to induce magnetism, not cut the magnetic field and generate power, so power generated is very small. It's more off trade-off depending on application about using mateiral that works for application and design of those parts. While concept works, it just won't be efficient at the end.
Also your gear needs to be compatible with metric or imperial system used to design bicycle, that's why chain was falling off.
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Eddy currents works both ways, in stator and winding, get the clue!
It will likely kill off any induction in wires and induction with those tiny magnets is very small comapre to surface area winding has.
Not to mention, coils in these motors are used to induce magnetism, not cut the magnetic field and generate power, so power generated is very small. It's more off trade-off depending on application about using mateiral that works for application and design of those parts. While concept works, it just won't be efficient at the end.
Also your gear needs to be compatible with metric or imperial system used to design bicycle, that's why chain was falling off.
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Brendan
AFAIK: It isn't so much that the number of magnets needs to be even, but more so that it is both even and ideally a common multiple of the number of phase coils. For a 3-phase motor, assuming 6 coils, one would then need either 6 or 12 magnetic poles (though 2 or 4 should also work OK. In contrast, 8 would likely have been be better for trying to convert a split-phase motor (or, in a BLDC, for optimizing for speed rather than for maximum torque and reducing the amount of cogging, though this effect should be more useful in a generator. Also with permanent magnets ideally one also needs a rotor with a fairly high magnetic permeability (such as silicon steel, etc.
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AFAIK: It isn't so much that the number of magnets needs to be even, but more so that it is both even and ideally a common multiple of the number of phase coils. For a 3-phase motor, assuming 6 coils, one would then need either 6 or 12 magnetic poles (though 2 or 4 should also work OK. In contrast, 8 would likely have been be better for trying to convert a split-phase motor (or, in a BLDC, for optimizing for speed rather than for maximum torque and reducing the amount of cogging, though this effect should be more useful in a generator. Also with permanent magnets ideally one also needs a rotor with a fairly high magnetic permeability (such as silicon steel, etc.
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LondonNight
I believe you would have gotten considerably greater results if you had used an unmodified rotor and stator for this job. I believe that the rotor not being ferromagnetic, together with the weak magnets, is what resulted in a low power output. I believe a squirell cage rotor, when properly excited, will create a very strong magnetic field, much stronger than any permanent magnet that can fit there. Also, watching you use an induction motor as a generator by having the squirell cage itself make the magnetic field would be awesome! :D
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I believe you would have gotten considerably greater results if you had used an unmodified rotor and stator for this job. I believe that the rotor not being ferromagnetic, together with the weak magnets, is what resulted in a low power output. I believe a squirell cage rotor, when properly excited, will create a very strong magnetic field, much stronger than any permanent magnet that can fit there. Also, watching you use an induction motor as a generator by having the squirell cage itself make the magnetic field would be awesome! :D
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Ojaswi
you can magnetize the rotor the start by using small amount of DC current through any of the winding for generating a voltage also for utilizing the output you have to place a three phase capacitor bank setup for stabilizing the output voltage, since voltages in induction motor as generator setups tend to collapse when subjected to change in loads. And if you have a constant value capacitor set the IMAG setup can only be used for a constant power output setup.
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you can magnetize the rotor the start by using small amount of DC current through any of the winding for generating a voltage also for utilizing the output you have to place a three phase capacitor bank setup for stabilizing the output voltage, since voltages in induction motor as generator setups tend to collapse when subjected to change in loads. And if you have a constant value capacitor set the IMAG setup can only be used for a constant power output setup.
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my
you're way too smart to quit with these results. That second motor could've got you there easily with reprinted magnet holder, 2x magnets per slot. That would be better than the og rotor because it would be lighter to turn. Use belt drive and a recumbent seat without the extra bike parts, make a flywheel for the primary drive mechanism so that it runs even if you stop pedaling for a few seconds.
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you're way too smart to quit with these results. That second motor could've got you there easily with reprinted magnet holder, 2x magnets per slot. That would be better than the og rotor because it would be lighter to turn. Use belt drive and a recumbent seat without the extra bike parts, make a flywheel for the primary drive mechanism so that it runs even if you stop pedaling for a few seconds.
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LOP1698
could you not drive the shaft get energy out of the shaft by hooking it up to 3 Phase and speeding the rotation to like 3'100-3'600 R/min(2 Pole/4 Pole half the rotation. etc (normely it would go 2600-2900R/min in 3phase 50Hz ) So you would essentialy Remove mechanical energie and you would give energie to the Electrical Grid.
At least thats my understanding of an Induction Motor.
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could you not drive the shaft get energy out of the shaft by hooking it up to 3 Phase and speeding the rotation to like 3'100-3'600 R/min(2 Pole/4 Pole half the rotation. etc (normely it would go 2600-2900R/min in 3phase 50Hz ) So you would essentialy Remove mechanical energie and you would give energie to the Electrical Grid.
At least thats my understanding of an Induction Motor.
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albi2k88
There on internet is couple videos of people using 2 or 3 capacitors to convert 3 phase motor to one phase AC generator without any motor modification (google result of AC 3 phase motor generator with capacitors. To start generating it needs slightly more RPM than normally that engine runs. With that caps 3phase motor can run on one phase (with reduced start torque.
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There on internet is couple videos of people using 2 or 3 capacitors to convert 3 phase motor to one phase AC generator without any motor modification (google result of AC 3 phase motor generator with capacitors. To start generating it needs slightly more RPM than normally that engine runs. With that caps 3phase motor can run on one phase (with reduced start torque.
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Jayaprakash
Try something like
start the induction motor with mains supply.
Get another prime mover mounted with the motor shaft.
Maintain the speed of the prime mover speed is equal to the motor speed.
Turn off the main supply and connect some electrical load to the motor terminas.
Maybe it gona work.
I guess.
reply
Try something like
start the induction motor with mains supply.
Get another prime mover mounted with the motor shaft.
Maintain the speed of the prime mover speed is equal to the motor speed.
Turn off the main supply and connect some electrical load to the motor terminas.
Maybe it gona work.
I guess.
reply
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