Attendees:

Tony

Asha

Naresh - Application Engineer from TQ

Andrew - Sponsorship contact from TQ

Goal: Investigate using motor for Drivetrain application

Application questions:

Mechanical questions:

How do we attach our shafts to the frameless motor rotor (I don’t see fastener features)?

High temp cured glue/epoxy. Will get more info on the integration process from Naresh.

How custom can the stator mounting be? Could we swap out the over-molded sections for metal for mounting? 

Don’t swap over-mold sections, need for sealing in glue. Glue stator to motor housing, see picture for glue specs.

For sealing, can we use some kind of spray-on (acrylic lacquer) conformal coating instead of over-molding?

Tentative yes for spray-on coating, as long as dielectric strength is up to par.

How is custom stator / rotor mounting done? How much is the typical cost for this?

See pictures for glueing solution

If custom mounting is too expensive, can we just use super-glue or similar industrial adhesives to glue magnets to a custom rotor? (Similar to our plan with the hoverboard motors)

Custom mounting can only be done on a business case.

How would we attach radial bearings to both sides of the stator?

Can be very custom given glue solution

Any available options where Rotor is on the outside and Stator is on the inside? (Similar to our current concept)

Magnetic field is inconsistent on the outside given that the motor is covered in overmold. Need to run the rotor from inside.

Motor PCB questions:

Are the shiny metal pads on PCB for connecting to the copper coils? Do we need to solder to these pads?

Landing pads, for motor coil configuration purposes (i.e. star vs delta).

Do you guys have any integrated strain relief on the soldered connections, or is the responsibility left to customer / motor housing design?

responsibility left to customer / motor housing design

Cost questions:

How much do these motors cost as is?

For Europe pricing is Euro 950 per stator and rotor. Could be completely different for TQ USA.

Sponsorship questions:

How much are we sponsored in-kind? Can unspent amounts carry over to next term?

Can we access any products / services you guys have?

Are there project limitations (i.e. are we entirely free to choose where to use the motors)?

(Most important) Will we be able to access project support like this meeting in the future as well?

YES.

Opinion questions:

Do you see this being a good application of these motors? 

Motor is not inherently back-driveable. If back driven, current produced in the coils will damage the motor because if wheel angular velocity exceeds some limit and results in coil voltage exceeding limit for motor.

Would you advise an alternative product?

Max motor operating temp: 125 celsius. Frameless design really allows good thermal dissipation and comes in at low weight (high torque density).

Using different motor coil configurations, can reach data-sheet specs with lower voltage supply.

Default configuration is Star-Serial, can swap interconnection to optimize for torque / speed goals.

Halving voltage supply doesn’t mean half torque, need double current to reach the same torque rating. Half voltage supply only halves maximum speed at no load.

Ensure BLDC motor driver supports back emf in sinusoidal wave form (not trapezoidal waveform)