Motor

Dana TM4 IPM200-33 Motor

As an EM spare part, the motor retails for $2,078 in the USA.  It is marked Dana IPM200-33.  IPM stands for Internal Permanent Magnet.  The companies Ashwoods and Dana TM4 have been associated with this motor.  Ashwoods is a UK company producing drivetrain components for electric vehicles.  As of June 2020, Ashwoods Electric Motors became Dana TM4.  Dana TM4 is a joint venture of Dana Corp. and the government-owned public utility Quebec Hydro.  It is headquartered in Boucherville, Quebec Canada.

The performance graphs were sourced from the old Ashwoods website.  

The ePure Race's motor nameplate says IP65, which stands for the Ingress Protection rating.  The first digit “6” is for solids, and means it is protected from total dust ingress.  The second digit “5” is for liquids, and means it's protected from low-pressure water jets from any direction.  The performance curves show both IP25 and IP65 variants.

The IP25 version has a higher continuous power rating likely due to better cooling – possibly using a fan.

The IP65 variant can sustain a continuous power output of 5 kW, and both types have a peak power output of slightly under the claimed 11 kW.  Peak torque is approximately 45 Nm (not 600 Nm as claimed by EM).

When I had the primary drive/flywheel removed, I could turn the motor shaft without extraneous interactions and felt 24 cogging positions.

Photo Credit: Ashwoods

Efficiency Plot

There's not a lot to say about this efficiency plot other than I really like the presentation format.  You can see there's a large sweet spot of 94 percent efficiency.  You can also see that very high torques and very low speeds (as might be needed in trials) can easily be less than 70 percent efficient.

Photo Credit: Ashwoods

It takes time and automated test equipment to make such a plot.  Imx Solutions is one company that makes this very specialized test equipment.  They have a nice YouTube channel.

Motor Position Sensor

The ePure's Dana TM4 motor position sensor is a sine-cosine encoder.  It is more sophisticated than the simple Hall switches used on the 5.7's Golden Motor.  It is also much more expensive.  The sin-cos encoder is EM P/N TC01O-40100-00-02 and it retails for $440.99.  

It is difficult to tell from the blurry video capture, but there is a flat area on the left side of the encoder in the adjacent photo that must align with a mating area on the motor itself.

The sine and cosine waveforms are sampled as analog signals by the motor controller.  When represented as polar coordinates, they give precise information on rotor position and can thereby resolve fractional shaft revolutions.

Credit: Ka Ulia Motors.  Sin-Cos Encoder

RLS AM4096

The SiliXcon controller manual shows the connection scheme for a sin-cos interface.   The units they recommend are manufactured by RLS in Slovenia.  RLS stands for Rotary and Linear Motion Sensors.  The RMK4 is an evaluation board for their AM4096 integrated circuit.  A small radially magnetized magnet must rotate above the IC at motor speed.

Credit: SiliXcon.  Sin-Cos sensor interface

Credit: kjmagnetics.com  “Radial Magnetization”

Oscilloscope capture showing the motor running at about 810 RPM

This oscilloscope capture shows the encoder's sine and cosine signals while the motor is running.  Because the waveforms are 90 degrees out of phase, the controller can determine both CW and CCW rotation.

The encoder produces one complete cycle of both the sine and cosine waveforms once per motor revolution. 

In this example, the time for one complete wave cycle is 74 ms (13.5 cycles per second).  This is the same as 810 cycles per minute (or 810 rpm).

Sensor Re-Calibration Process

I have not needed to use this procedure, but it seems like a handy thing to know. 

John at Ka Ulia Motors in Hawaii demonstrates the process in the adjacent YouTube video. 

In summary: Have the bike on a stand.  Press and hold the map button (about 14 seconds) until you hear the motor emit a brief tone.  Release the map button.  The rear wheel will start and stop rotating slowly on its own 3 times without the rider applying any throttle.  The re-calibration is complete. 

Map-Tone Origin

Every time the map button is pressed an audible tone is generated.  I wondered where it comes from and figured SiliXcon is using the motor itself as a transducer.  With the bike up on a stand, you can feel the chassis vibrate, and the rear wheel even moves very slightly if it's in the correct rotational orientation.

Typically microprocessors use a piezoelectric “buzzer” for annunciation - usually at around 5 kHz.  I'm guessing the EM's tone is more like 500 Hz, and you can feel it.  The motor is the only thing on the bike that could do that.

I laid an audio transducer connected to an oscilloscope on the motor and pressed the mode button.  It was a bit hard to discern, but I believe the PWM switching frequency is about 20 kHz and the audible tone is about 430 Hz.  Both of these numbers make sense to me.