@chaitanya.hegde, would you happen to have a picture of the waveform post processing?
Whatever little that I managed to capture did not show a change in amplitude or duty cycle as the motor was spun up from 0 rpm. I’m havig a hard time imagining how what I saw could be a small slice of a larger sine wave.
Found this from google. I hope this is what @chaitanya.hegde meant when he said both are mostly similar.
This says the same thing in the excerpt.
What is confirmed now is that the motor remains the same between the 450 and X. Question is whether it’s a DC or an AC motor.
First of all, My language got mishandled.
To address your question starting from first when I say expert I mean the actual engineer who know how to divide and measure the current rating and have years of experience in handling probing
I too have a Bench Osiloscope 100mhz 1gs/s 2 port
As mod notes, I’m trying to get a 450x to be opened soon and post my findings here
As the product engineer here has already mentioned as the resolution on the scope cannot be visible in the Handheld/portable scope to actually see the Sinewave on needs to divide the rate/ms or volts/dev into a proper visible screen, since you used a laptop screen for a very short time the wave is showing its initial stage which is not forming sinewave(my theory)
No, I don’t need to travel to Bangalore to prove something that I already know, why should I spoil your fun in exploring in your own way
This is why both models are the same motor in both 450s and 450x
450X 450They both have the exact model number AMK6157 48v 3.3kW
This should be interesting. I am quite keen to see what you find.
Made in Slovenia? 
So the 450 and 450X have the same motor ?? Both BLDC??
Yes both are same. They changed the terminology to PMSM motor in case of 450X. As theres is a loophole (I preferred to use this word as I think it is) in the industry where some experts consider BLDC motor as a PMSM motor by definition and hence they used this name.
But if we look at it in a technical perspective BLDC and PMSM are different as they both have different waveforms.
The very first powertrains were imported. At some point, they switched to Indian manufactured units, and have been using the same ever since.
Yup.
Very much this.
Yes, even my 450 has a motor made in Slovenia. I think since the initial demand versus supply was limited the motors where imported. but since now they have a bigger factory which can pump up to 10000 units per month makes no sense in importing and paying additional duties. Mahle already has many plants in India for its automotive industrial supply. so making it here would make more cost-efficient.
I have been reading this for a while now, they do sometimes have different waveform they have a different power delivery system from what I have found in a few papers. Think of it as PWM signal the voltage goes up to a certain point then drops immediately and then tries to do this again and again which forms a square wave.
Now Ather claims they have smoothened the power delivery to the motor hence the term PMSM which can slowly raise the power until the magnets inside the motor aligns with the electromagnets and then drop it then power it again, like a smooth Sinewave.
Until technically proved yes
This is really interesting, especially @blackworks who got us hard data. I’m with him/her and ask anyone who wishes to trash the questions to come with similar data as well.
I can affirm as an electrical engineer (who did not forget the knowledge gained during B.Tech. the moment he stepped out of college like so many people proudly announce) that PMSM and BLDC are indeed taught as basically the same thing looked at from slightly different perspective.
I am not sure how to interpret what @chaitanya.hegde is referring to though. First of all, @blackworks’s image seems to me to not be at a high enough resolution to clearly say whether it is a sinusoidal shape or a square shape. And, PWM is normally used as the activation signal for the power electronics in the drive to produce the final current output for the motor, even if the latter is a sinusoidal wave. So unless the signal recorded was an input to the drive, rather than the output of the drive, I would expect to see a sinusoidal signal rather clearly.
The signal is the output from the controller / input to the motor. Unless there’s funky stuff built into the motor itself, there’s no “post processing” applied to it.
The signal was being sampled while the motor was turning and driving the rear wheel, so it’s not an aberration. If you look closely at the video, you’ll notice that there’s no variation in amplitude; only frequency. A sine wave would have shown up as amplitude change, even ASSuming that the resolution wasn’t right, as some here seem to be implying.
Not that I have anything to prove to anyone, but I will redo this once I get a 4 channel PicoAuto scope and inductive current probes, whenever they arrive.
Yeah I noticed the lack of amplitude changes, and that tells me there’s an issue with the way its being measured (for sure). Voltage amplitude must change with throttle. What I don’t know is what the issue could be.
Not necessarily. Voltage can remain steady and frequency can change too. Greater the frequency of voltage pulses to the motor, higher its speed.
Hence the wait for inductive clamps.
The fundamental reason for this exercise was to establish that the motor between the old and new models was the same, and not updated like Ather tried to lead people to believe. Now that it has been confirmed, the only thing left is to test the veracity of this post processing explanation.
Nope, frequency must match the speed of the motor (multiplied by number of poles), else it cannot apply ANY net torque to the wheel - because it’s a synchronous motor.
It is voltage that has to change with the throttle because that’s what allows you to vary torque. And we know from experience that the accelerator in the 450x (or for that matter any two wheeler ever), controls torque directly and speed only indirectly.
Ideally, torque on a motor is supposed to be flat from 0 to redline. Switching modes should vary max torque (probably by varying the duty cycle), but in a given mode, all the throttle lever needs to do is command output frequency and thus motor speed.
Consider a LED, for example being driven by a square wave type signal. Changing DC while keeping frequency constant varies its intensity, and changing frequency while keeping DC constant changes the blink rate.
Variable rate fuel pump motors on cars work similarly. The input signal to the driver from the ECU is a PWM indicating the desired speed, and the output from the driver to the pump is fixed DC variable frequency.
All this is my understanding of how this stuff probably works, and can be wrong. If someone else is inclined to measure things for themselves and publish the results here, I’d be very keen to see and read.
Thanks for sharing was eagerly looking for ather 450x disassembly videos on youtube without success
