Best SOUNDING Mid drive motor for electric motorcycle?

[SunAnnouncer]

I love electric vechicles to death but my biggest pet peeveis motors that give you that mosquito sound, usually mid drive motors with high RPM. Hub motors tend to do very well here, the sound is usually more low end and very nice. When i build i would like to avoid hubs becuase i want to do some demanding offroad.

So, does anyone know of any powerful mid drive that has a nice, lower pitch sound? I would be very grateful

an example would be https://youtu.be/PI-OT6-TZRA?t=18 at the timestamp.

 

[amberwolf]

The faster the motor spins, the higher the pitch the motor will make, but the motor itself can be virtually silent when driven correctly by the controller. If the controller is the typical trapezoidal type, you can change it out for an FOC controller instead, and when you are done tuning the controller to the motor and system, the motor noise should be gone.

The hubmotors can also be made virtually silent the same way. (they are lower pitch because they spin MUCH slower than the middrive motors, though a geared hubmotor is several times faster than the DD hubmotor, and it's gearing will still have a sound, see below).

The gearing to translate the higher middrive or geared hub motor speed into torque will also make a sound, depending on it's design and the size of the gears relative to each other and the input and output speeds.

It's likely that most of the noise of most drives comes from this source. So if you are willing to build your own middrive, you can choose gearing designs that are much quieter than the typical ones used (which are often chosen for their cost to build and sometimes their size, rather than other qualities).

 

[SunAnnouncer]

The faster the motor spins, the higher the pitch the motor will make, but the motor itself can be virtually silent when driven correctly by the controller. If the controller is the typical trapezoidal type, you can change it out for an FOC controller instead, and when you are done tuning the controller to the motor and system, the motor noise should be gone.

The hubmotors can also be made virtually silent the same way. (they are lower pitch because they spin MUCH slower than the middrive motors, though a geared hubmotor is several times faster than the DD hubmotor, and it's gearing will still have a sound, see below).

The gearing to translate the higher middrive or geared hub motor speed into torque will also make a sound, depending on it's design and the size of the gears relative to each other and the input and output speeds.

It's likely that most of the noise of most drives comes from this source. So if you are willing to build your own middrive, you can choose gearing designs that are much quieter than the typical ones used (which are often chosen for their cost to build and sometimes their size, rather than other qualities).

Thanks alot for this response, I think the best way to go would be to use a larger motor with a larger diameter that has more torque and therefore can run good at a lower rpm, and use belt drive?

Im not sure what the difference between a regual motor controller and a FOC controller is, can you recommend a controller as an example? I would greatly appreciate it

 

[amberwolf]

Typical (especially cheap) ebike and scooter motor controllers use trapezoidal drive in a fixed pattern, not adapting to the particular motor being driven (so some motors are noisier than others on the otherwise-same-system, but they generally drive "any" motor out of the box).

FOC controllers (like the many VESC variants, Lebowski's brain chip, Sevcon, some of the various controllers developed here on ES, ASI, Phaserunner/Baserunnner (ASI-based), and others) use a sinusoudal (sine) drive in a pattern generated for the specific motor being driven (per the settings the user inputs during controller setup), so the motor can be driven as closely as possible to the best possible way for that specific motor. If the system is not setup correctly for that specific motor, it may either not run correctly, or at all, or even damage the controller itself if it's really badly setup, so setting up and tuning these controllers is critical to correct operation. Some have so many possible parameters that it can take someone experienced with that controller and putting the system on a dyno to really set it up optimally. Some have a decent autotune routine that will get you close enough to tune the rest of the way yourself.



People have built midrives out of hubmotors; there is a thread titled something like the hubmotor mid drive media group showing some of these. APL has a series of builds using his own axial-flux motors this way; the frames could use hubmotors instead with some modifications.

 

[chuyskywalker]

When i build i would like to avoid hubs becuase i want to do some demanding offroad.

sidenote: you can absolutely do off roading with hubs, but it will require a higher wind count motor and/or more amps than a road vehicle, but it's entirely doable. Especially if you get into the larger hubs (like the qs 273). Or you can go AWD to easily double your power-to-ground (but then have to be more careful about using front wheel power too).

But, of course, nothing beats the torque enhancement of a gear ratio