Is Magnet in pmac motor degrade while they are in use because in tesla model 3 they uses pmac motor so we have to replace magnet frequently ?
Electrical – Permanent magnet in ac motor
brushless-dc-motorelectromagneticmagnetmotor
Related Solutions
Finally found the closest thing to an answer, thanks to hints from David Kessner and Ignacio Vazquez-Abrams.
A pancake motor (AKA Floppy Drive motor) has a planar separation between the rotor and stator, and so is most suitable for working through a sheet of glass.
I am aware that I will not be able to produce more than 100W anyway.
That's about right. Another useful number to remember is that a servant can give about 1 kWh per eight-hour shift!
If I buy a motor with 24V 350W RPM2750 will I be able to run appliances which consume more power rather then I would purchase a motor 24V 250W RPM2750?
There will be losses in any motor / generator and these will increase with size although they may be countered by improving efficiency. The 250 W unit will have lower inertia and will probably be cheaper.
Does it mean that the motor with higher wattage will be more effective in running appliances which consume more power?
Yes, but as you've stated, your power source (you) is limited in output.
As I understand, the adult person is able to run the bicycle with more or less RPM 60, so it means that in an hour I will be able to do RPM 360, ...
Umm, 60 RPM x 60 minutes = 3,600 revs/hour - but why are you converting to hours?
which is 7 times smaller then RPM2750.
Much worse than you imagine: \$ \frac {60~rpm}{2750~rpm} = 2\%\$ of rated speed giving you 2% of 24 V = 0.5 V out. This won't light an LED! The DC generator's output voltage will be proportional to rotational speed.
The article is too long for me to read but here are a few pointers:
- You need to figure out what voltage your system requires.
- You need to generate in excess of that voltage and regulate it. (It is also possible to generate a lower voltage and boost it with a boost regulator.)
- If you go for 24 V out then you need to gear-up the motor drive to give 2750 RPM at your preferred cadence.
- You need to figure out what you want to happen when you stop pedaling for a second or a minute. Do you want your cinema to reboot? If not you need some short-term storage.
I think a more practical project would be to power your cinema from a mains-powered battery and the bicycle generator. Monitor the generator output and if you fall below a certain threshold for a time then blank the video. If you maintain output for more than ten minutes then dispense a chocolate reward.
Related Topic
- Electronic – arduino – Permanent magnet DC motor earth wire
- Electrical – How to determine a Permanent Magnet Synchronous Motor (PMSM) Nameplate
- Electrical – Can an Induction motor be called a BLDC motor if operated from a DC supply
- Electronic – Permanent magnet synchronous motor (PMSM) equivalent circuit
Best Answer
In a properly designed motor, no, they will not degrade. This sort of thing was a problem with older permanent magnet materials (if you are old enough you might remember the need for 'keeper iron' on the magnets at school) but with modern rare-earth magnets this is not a problem.
A permanent magnet is essentially a magnetic material with an extremely large B-H curve hysteresis. When you apply a large magneto-motive force (MMF) across the material, the magnet retains most of this force when it is removed. To demagnetize the magnet, or reverse the polarity, you have to supply a sufficiently large MMF in the opposing direction to 'snap over' to the other side of the hysteresis curve. In old magnetic materials, even the reluctance generated by the airgap between the poles could be sufficient to do this (hence the need for keeper iron), but with new materials the required MMF is so large that specialist magnetizing equipment is typically required.
If the motor is poorly designed, then it is possible that under transient conditions this could occur, but in most motor typologies the backing iron will saturate long before a sufficient field can be generated to demagnetize the permanent magnets. However, at a critical temperature permanent magnetization can be lost in most permanent magnet materials, so this remains a real risk if internal temperatures are not carefully managed.