Greg Spalding Posted September 14, 2016 Share Posted September 14, 2016 all this reminds me of the way KITT from the original Knight Rider series used to sound when driving by https://en.wikipedia.org/wiki/KITT Link to comment Share on other sites More sharing options...
Keith Posted September 14, 2016 Share Posted September 14, 2016 2 hours ago, Greg Spalding said: a characteristic of the MOSFETs and the motor.... it's just the harmonics of that situation and UNalterable. If my MOSFETs started screaming I'd be very worried. Actually it is the PWM frequency. (Pulse Width Modulation). To prevent MOSFETs burning out they are either on or off, never anything in between or the MOSFETS would have significant resistance which would generate significant, read way too much, heat, So to control the power fed to the motor it is sent in pulses, short pulses, or more accurately a short duty cycle, for low power longer duty cycle (more 'on' than 'off') for higher power, all this on top of also timing which of the three phases the pulses are going down depending on which magnets are in the right place to give them a push or pull. those pulses have to be sent at a frequency that is high enough to to not make the motor control jerky but low enough to cope with the inductance of the motor windings, unfortunately that frequency tends to end up in the 8kHz to 12kHz range, anything higher and therefore less audible needs a very low inductance motor, ideally it would be at least 24kHz so it only upset dogs ;-). The last part of the equation is that a speaker is an electromagnetic coil of wire next to a permanent magnet, an a.c audio frequency signal sent through the coil makes the magnet move at that frequency and generate sound - pretty much exactly the same thing as an electric motor. I suspect that the reason some motors are a lot noisier than others, does indeed come down to harmonics I.e. how easily that motor can vibrate at the audio frequency the PWM is generating. It does mean it could be prevented or at least heavily reduced if the motor was designed such that it cannot resonate at that frequency, I suspect that would be a challenging design issue. Link to comment Share on other sites More sharing options...
Greg Spalding Posted September 14, 2016 Share Posted September 14, 2016 2 minutes ago, Keith said: If my MOSFETs started screaming I'd be very worried. Actually it is the PWM frequency. (Pulse Width Modulation). To prevent MOSFETs burning out they are either on or off, never anything in between or the MOSFETS would have significant resistance which would generate significant, read way too much, heat, So to control the power fed to the motor it is sent in pulses, short pulses, or more accurately a short duty cycle, for low power longer duty cycle (more 'on' than 'off') for higher power, all this on top of also timing which of the three phases the pulses are going down depending on which magnets are in the right place to give them a push or pull. those pulses have to be sent at a frequency that is high enough to to not make the motor control jerky but low enough to cope with the inductance of the motor windings, unfortunately that frequency tends to end up in the 8kHz to 12kHz range, anything higher and therefore less audible needs a very low inductance motor, ideally it would be at least 24kHz so it only upset dogs ;-). The last part of the equation is that a speaker is an electromagnetic coil of wire next to a permanent magnet, an a.c audio frequency signal sent through the coil makes the magnet move at that frequency and generate sound - pretty much exactly the same thing as an electric motor. I suspect that the reason some motors are a lot noisier than others, does indeed come down to harmonics I.e. how easily that motor can vibrate at the audio frequency the PWM is generating. It does mean it could be prevented or at least heavily reduced if the motor was designed such that it cannot resonate at that frequency, I suspect that would be a challenging design issue. as always, i appreciate the education and sorry for my misinformation earlier please remind me why the ninebot one E+ has a much LOWER frequency and still doesn't feel "jerky" when ridden thank you, as always, in advance Link to comment Share on other sites More sharing options...
Kustor Posted September 14, 2016 Share Posted September 14, 2016 2 hours ago, Morgan said: My V2 MSuper seems about the same, but I like it - sounds like a tiny jet engine. .... the question is what road users think or say when a tiny jet engine or even Kitt passes them at full volume.... ... the expression on their face are an expression of the relative loudness of sounds in air as perceived by the human ear. Link to comment Share on other sites More sharing options...
Tilmann Posted September 14, 2016 Share Posted September 14, 2016 23 hours ago, Donafello said: Hey tilman. Did you ever figure out that wobble at high speed? Hi again, did some high speed runs today (45.11 kph GPS, 45.8 kph shown by Wheelog app) and I'm excited to report, the wobbling tendency disappeared altogether! As I was trying different foot positions, I am now leaning towards the theory, that the new tire caused the initial swinging motion and it simply needed some braking in. Going that fast felt deceivingly natural - like, it was always meant to be that way . For the record: I was all wrapped up in a tank-like motorbike leather jacket with protectors everywhere, helmet, protective goggles and wrist guards. Must have looked like the Michelín mascot for those of you old enough to remember the adverts. Link to comment Share on other sites More sharing options...
Donafello Posted September 14, 2016 Share Posted September 14, 2016 1 minute ago, Tilmann said: Hi again, did some high speed runs today (45.11 kph GPS, 45.8 kph shown by Wheelog app) and I'm excited to report, the wobbling tendency disappeared altogether! As I was trying different foot positions, I am now leaning towards the theory, that the new tire caused the initial swinging motion and it simply needed some braking in. Going that fast felt deceivingly natural - like, it was always meant to be that way . For the record: I was all wrapped up in a tank-like motorbike leather jacket with protectors everywhere, helmet, protective goggles and wrist guards. Must have looked like the Michelín mascot for those of you old enough to remember the adverts. NICE. That speed is new territory for euc's. I think the msuper v2 would cut out at about 43km so I think its safe to say that the 50km/hr factory top speed is accurate Link to comment Share on other sites More sharing options...
Tilmann Posted September 14, 2016 Share Posted September 14, 2016 15 minutes ago, Donafello said: NICE. That speed is new territory for euc's. I think the msuper v2 would cut out at about 43km so I think its safe to say that the 50km/hr factory top speed is accurate Sorry to disappoint, but you won't find me trying to push it to 50 kph . With the lift test, the Wheelog app shows a cut out speed between 52 and 53 kph. I think, I will reserve going up to 45 kph for ideal conditions like today: slight tail wind, perfectly even runway, full battery and ample body armor. Link to comment Share on other sites More sharing options...
MaxLinux Posted September 18, 2016 Share Posted September 18, 2016 On 9/13/2016 at 0:02 PM, The Fat Unicyclist said: Now that is interesting... My IPS191 does not do this. When the charger is plugged into the wheel first there is no light on the charger. I know IPS made some changes to the unit - mine uses the new IamIPS app (not the older Xima version). So now I'm wondering if there were other changes too? @MaxLinux - what version of app does your wheel use? This may support (or completely disprove) the theory... Your comment caused me to observe more carefully, and here is what I found: when connecting the charger to the wheel (but not mains) AFTER A RIDE BUT BEFORE CHARGING, the LED does not light up. AFTER CHARGING, if the charger is disconnected from mains but still connected to the wheel, the LED glows bright green for a while, then dim green for a while, then off. Link to comment Share on other sites More sharing options...
ElectricWheelEric Posted September 18, 2016 Share Posted September 18, 2016 It's weird that I've been told by @Linnea Lin Gotway and @Jane Mo that I lost the factory warranty due to riding through poddles, but I haven't done that, and now Ian was testing v3 the same way and I can't see any post from a GotWay staff. How's that?? The story is that my axle snapped while I was riding my v2 and been told I won't get new motor because I didn't ride it as it should be. How can they say that? How do they knoiw that?? In fact, I was looking after it as muc has I could and there you go, I'm still fighting, but no replies at all. Is this the way they treat customers? Wouldn't you consider buying from them from now on? What happens if you received a faulty model? What is the guarantee that you will get reimburset or compensated for that??? As far as I know I'm not the only one having this problem so far and I'm asking your help to fight against this as it could lead to severe injuries or even death. My right knee and shoulder is still hurt even though i was wearing protectives and wasnt ridning that fast as i was about to slow down. So this is gotway's true face to handle aftersale complaints, ignoring customers. Thanks for reading... Link to comment Share on other sites More sharing options...
Marty Backe Posted September 18, 2016 Share Posted September 18, 2016 12 minutes ago, ElectricWheelEric said: It's weird that I've been told by @Linnea Lin Gotway and @Jane Mo that I lost the factory warranty due to riding through poddles, but I haven't done that, and now Ian was testing v3 the same way and I can't see any post from a GotWay staff. How's that?? The story is that my axle snapped while I was riding my v2 and been told I won't get new motor because I didn't ride it as it should be. How can they say that? How do they knoiw that?? In fact, I was looking after it as muc has I could and there you go, I'm still fighting, but no replies at all. Is this the way they treat customers? Wouldn't you consider buying from them from now on? What happens if you received a faulty model? What is the guarantee that you will get reimburset or compensated for that??? As far as I know I'm not the only one having this problem so far and I'm asking your help to fight against this as it could lead to severe injuries or even death. My right knee and shoulder is still hurt even though i was wearing protectives and wasnt ridning that fast as i was about to slow down. So this is gotway's true face to handle aftersale complaints, ignoring customers. Thanks for reading... My sense is that we are at the 'wild west' stage of EUCs. The manufacturers are in China with marginal non-Chinese language skills, and sketchy customer support. That's why I think it's imperative to purchase from a local (as local as possible) supplier and deal with the supplier if there are problems. But my expectation is if there's a major problem I'll probably just have to eat the cost. There's nobody forcing us to buy and use EUCs, and if we want to enjoy this activity in today's market, we have to live with the financial risks. Keep in mind these are not priced like cars, motorcycles, etc. Fortunately, the vast majority of us don't have major problems, so the risk is manageable. You, unfortunately, drew the short straw. Good luck. Link to comment Share on other sites More sharing options...
Greg Spalding Posted September 18, 2016 Share Posted September 18, 2016 44 minutes ago, Marty Backe said: My sense is that we are at the 'wild west' stage of EUCs. The manufacturers are in China with marginal non-Chinese language skills, and sketchy customer support. That's why I think it's imperative to purchase from a local (as local as possible) supplier and deal with the supplier if there are problems. But my expectation is if there's a major problem I'll probably just have to eat the cost. There's nobody forcing us to buy and use EUCs, and if we want to enjoy this activity in today's market, we have to live with the financial risks. Keep in mind these are not priced like cars, motorcycles, etc. Fortunately, the vast majority of us don't have major problems, so the risk is manageable. You, unfortunately, drew the short straw. Good luck. i concur, sadly, but wholeheartedly maybe things will be different one day but i think if you spend anything OTHER than "disposable income" for a wheel it might be a mistake i'm not trying to offend anyone and i don't claim that $1,800.00 USD SHOULD be "disposable" to ANYONE... but, i think that's the attitude you MUST have when purchasing one of these cool devices. Link to comment Share on other sites More sharing options...
ElectricWheelEric Posted September 18, 2016 Share Posted September 18, 2016 Hmm, well, fair enough, cant deny, it's better to wait and save a bit more and buy from a (local) distributor than directly from the factory, but in the same time it's a bit scary too... Link to comment Share on other sites More sharing options...
HEC Posted September 20, 2016 Share Posted September 20, 2016 On 18/09/2016 at 7:18 PM, Marty Backe said: That's why I think it's imperative to purchase from a local (as local as possible) supplier and deal with the supplier if there are problems. But my expectation is if there's a major problem I'll probably just have to eat the cost. Unfortunately purchasing from local distributor or reseller will not be much of help in case of serious injury or (god forbid) worse outcome of your crash due poor manufacturing quality and irresponsibility of the company producing unsafe and way to fast EUCs ... Link to comment Share on other sites More sharing options...
Greg Spalding Posted September 21, 2016 Share Posted September 21, 2016 1 hour ago, HEC said: Unfortunately purchasing from local distributor or reseller will not be much of help in case of serious injury or (god forbid) worse outcome of your crash due poor manufacturing quality and irresponsibility of the company producing unsafe and way to fast EUCs ... A very true point And if the new 84 V board make this unit even faster the company has proven to us they really don't care to have repeat customers Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.