I am comparing async induction motors with synRM and PM motors and noticed that, although the efficiency of a SynRM motor is a bit higher compared to induction, the current is much higher. Example: 110kW 4pole @100% load. IE5 synRM: eff: 96,8% - 243 amp IE4 async induction: eff: 96,3% - 194 amp IE5 PM motor: eff: 97,2% - 191 amp This difference in current is Around 20% which is a lot. Now the only way I can explain the much higher current of the SynRM is that the VFD would sent out a much lower voltage level @ full speed but: A) is this correct? B) would this mean thicker cables between the drive and motor compared to induction and PM? C) in the end the energy company charges us the kWh we use. As we need more current for the synRM would it not mean a higher energy bill and CO2 footprint? Any other advantages/disadvantages of synRM compared to the the other types of motors?
Hey everyone, came up with a question the other day. In hobby applications, such as RC cars and planes, BLDC motors are extremely common. All of the motors and applications I've encountered use synchronous motors with permanent magnets in the rotor. Why aren't reluctance motors used? I was reading about the motors used in electric vehicles, and those are very commonly switched-reluctance motors, which seem to offer advantages over the conventional PMSM. Is is due to the cost of the motor (or controller), complexity, or is there some other reason? Thanks!
I'm wondering if any other teams have considered using SRM motors (https://en.wikipedia.org/wiki/Switched_reluctance_motor) rather than the normal Brushless Permanent magnet motors that are most commonly used. According to this abstract: https://ieeexplore.ieee.org/abstract/document/8385282 , SRM motors have "higher torque to power ratio, low losses" and also don't suffer from thermal de-mag due to not actually having permanent magnets. These all sound very beneficial to a solar car motor, but perhaps the larger torque ripple makes it not worth the benefit?
I'd really appreciate feedback from anyone with more experience designing motors, it's a complicated field that I'm doing my best to break into!
I understand that for regenerative braking basically an EMF needs to be induced onto the stator coil. And for that you need a changing magnetic field around the stator coil. But if the rotor does not have any permanent magnet which means (this is my understanding) that even if it rotates, the magnetic field (flux) associated with the stator is not going to change and hence not going to induce any EMF.
Am I right or wrong? If wrong can anyone explain what is the correct behaviour and why?
Hey, I'm looking into switched reluctance motors as an alternative to BLDC, anyone have an recommendations for cheap motors to buy or resources? Motor specs don't matter that much as I would build my own controller.
Hey, very specific question for you all.
I'm trying to run the motor from a Dyson handheld vacuum cleaner using an Arduino and a couple of MOSFETS. I've got it spinning, but it's super graunchy and needs hand starting then ramping up. If I bring the frequency too high it dies on me.
Anyone know if it's possible to control one via very dumb open loop, or if I have to build a full controller system with current sensing? I don't need any power out of it, I just want it to spin at a specific frequency.
I can find very little information on actually controlling switched reluctance motors online, and even less on these low power, two pole versions.
Thanks!
(The irony of this is that I actually work just the other side of the wall from the guys who designed the control systems for the handhelds, but they insist it's all magic and fairy dust and that us peons can't understand it. After getting a Supersonic motor to spin using just a stepper motor driver I'm determined to prove them wrong, but that's not the primary goal here. That's actually a synthesiser using vacuum cleaners...)
From what I can find on the internet, SynRM motors use the sinusoidal waveform and doesn't have salient poles like a switched reluctance. Doesn't that make it an induction motor? how is it any different?
I also recently read that Tesla has switched to a switched reluctance motor. From what I can find, it's noisy and has torque ripple. But it doesn't produce much heat in the rotor. Why is that? Current must be induced in the rotor like an induction motor. Shouldn't it too produce heat just like an induction motor?
And why is that motor controller for induction motors are said to be more expensive than DC motor controllers for EVs (this seems to be true while looking at Alibaba and EVWEST pricing)?Both BLDC and induction run on "AC". They just use different waveforms. Is making a sinouduial waveform more complicated than switched waveform (I don't know the right term)?
And how come Axial flux motors so hard to make? I read that windings are more complicated. But how are they more complicated?
Please ELI5 because I am a Meche and electricity is witchcraft to me.
Hey guys, My professor assigned a project where we have to teach a reluctance motor to class... but our book doesn't explain how it works, and online has fairly sophisticated explanation. Can any of you guys explain how it works on a very simple level?
My basic understanding is that there is a magnetic rotor between two electromagnetic. Torque is created by switching the electromagnets at the appropriate time... Please help!!
So the electric revolution is coming and having a working knowledge of what makes particular electric motors in cars feel different might be a good thing to know about. So what i'm talking about is for instance with the difference between diesel and petrol ICE we know that one will generally have a lot of torque and the other will be able to rev freely or a long stroke ICE will have more torque but rev less that an over square design, all things being equal bigger displacement *generally* equates to more power etc.
Essentially what i'm asking is what do you think are the defining characteristics of electric motors and how they perform.
This time of year, trouble lurks in the shadow of my graveyard. It’s because of the winter holidays, you see—bereaved families come to visit, their outpouring of emotion gets the 'locals' all riled up, then anyone caught here after sundown is liable to have an encounter.
That’s what happened with poor Mrs. O’Reilly. I spotted her through the window of my shack, wandering past a row of headstones from the nineties. There was a dry winter breeze and mist so thick you couldn’t see your own shoes; definitely not a night you wanted to get stuck outside.
I pulled on my raincoat and gloves and caught up to her on the flank of a steep hill, close to a headstone dated October 13th, 1997.
“Good evening,” I said.
She shrieked and spun around.
I leaned back. “Didn’t mean to startle you. I’m Sean, the groundskeeper here.”
She put a hand to her chest and said, “Oh, I’m so sorry. You scared the absolute bejesus out of me.”
“My apologies.”
Wind hissed through the crooked branches of skeletal trees on either side of us. I looked around then said, “That breeze must be cutting you to the bone, what are you doing out here at this hour?”
“Well, I’m afraid I lost my bearings. I can’t even remember which way I came.” She whipped her head from side to side. “It feels like I’ve been going in circles. I really need to get home to my daughter, she must be worried sick.”
I had to get the lady inside before the situation became dangerous. “Not to worry. Come with me, I’ll take you over to the gate.”
“That would be wonderful. Thank you, Mr…” Her voice trailed off, waiting for me to fill in the rest.
“Donnelly. But you can call me Sean.” I tipped my cap.
“Pleased to meet you Mr. Donnelly.”
The path curved in a lazy S-shape. It was a narrow lane, with brambles and bushes to the left and a row of headstones on the right.
“How long have you worked here?” she asked, then breathed into her cupped hands.
“Coming up on twenty-five years.”
“And does it ever bother you?”
“What?”
She gestured toward a nearby headstone. “Being so close to the…you know. I’d imagine you’ve had a few frights over the years.”
“Only when I get my pay cheque.”
She chuckled. “It’s funny, I’ve never thought of myself as superstitious, but as soon as the sun went down I started picturing corpses springing out of their graves. I half-expected a rotted hand to snatch my ankle.”
“When that happens, it’s best to bash ‘em with a shovel. Usually sends ‘em right back to sleep.”
She stared at me.
“Kidding
... keep reading on reddit ➡I am comparing async induction motors with synRM and PM motors and noticed that, although the efficiency of a SynRM motor is a bit higher compared to induction, the current is much higher. Example: 110kW 4pole @100% load. IE5 synRM: eff: 96,8% - 243 amp IE4 async induction: eff: 96,3% - 194 amp IE5 PM motor: eff: 97,2% - 191 amp This difference in current is Around 20% which is a lot. Now the only way I can explain the much higher current of the SynRM is that the VFD would sent out a much lower voltage level @ full speed but: A) is this correct? B) would this mean thicker cables between the drive and motor compared to induction and PM? C) in the end the energy company charges us the kWh we use. As we need more current for the synRM would it not mean a higher energy bill and CO2 footprint? Any other advantages/disadvantages of synRM compared to the the other types of motors?
