Larsb review of 72124 motor

EFOIL.builders Propulsion System (Motor, Gears)
81

You are right. I totally forgot to set the right material for the rotor :rofl: :sweat_smile:

Let me come back in a couple of minutes with something updated.

82

Ok so here it is :sunglasses:

I’m working with a model I designed that I think very close to the reality :

image
image795×926 35.2 KB

(This is 45° of the rotor / stator assembly).

So, based on this model here is what I have :

Current situation :

  • Connection type : Delta
  • Strand diameter : 0,4mm
  • Strands in hand : 7
  • Estimated wire insulation thikness : 0,005 mm
  • Number of turns : 11

Gives me following data :

  • Conductor area : 0,8796 mm²
  • Insulated wire fill factor : 26,48%
  • No-load speed (rpm) : 5411 at 55V => 98kV

These data are in line with what’s been advertised by @Konstantin_Cunichin (minus copper area / wire fill factor). I’ll therefore consider my motor model valid for following optimizations.

Optimized model considering @Larsb 2mm² rectangular wire :

Larsb’s proposal (8T delta) :

  • Connection type : Delta
  • Strand width : 2 mm
  • Strand height : 1 mm
  • Strands in hand : 1
  • Estimated wire insulation thikness : 0,1 mm
  • Number of turns : 8

Gives me following data :

  • Conductor area : 2 mm²
  • Insulated wire fill factor : 55,01%
  • No-load speed (rpm) : 7440 at 55V => 135kV
    => Beware, stator lamination is not optimum for such speeds, efficiency will decrease.

Sliman’s proposal :

  • Connection type : Star
  • Strand width : 2 mm
  • Strand height : 1 mm
  • Strands in hand : 1
  • Estimated wire insulation thikness : 0,1 mm
  • Number of turns : 6

Gives me following data :

  • Conductor area : 2 mm²
  • Insulated wire fill factor : 41,26% (way easier to wind even by machine)
  • No-load speed (rpm) : 5597 at 55V => 102kV

=> around 20% more troque at up to 70% of rotor speed compared to Lars’b proposal

Your turn to choose. In the end it’s a compromise between torque and speed :wink:

4 Likes
83

No, it’s not since i will have a battery and controller that i think can saturate the laminations at both kVs. But i agree on the RPM vs lamination thickness. It doesn’t make sense to run this motor at 7500RPM

Also your motor model is theory while i have measured real kV of this motor so my figure is correct. It’s 109kV.

84

Not sure about this. Konstantin measured the Kv with Vesc tool prior to sending and said they all where 98kV if memory serves. See here :

85

Yes, might be the case but i trust my generator kV measurement more than VESC controller kV since the kV is a motor parameter, when measured in generator mode you get no effect from ESC.

86

Your choice, just wanted to help :wink:

87

Yes, sorry, i appreciate it actually. You only get so far alone so a discussion is always valuable :+1:

88

Hi @Larsb , how is the rewinding going? super interested on how many turns you were able to fit?

89

When I saw Franks(@JetboardCologne) post that motor production costs could be near ~50EUR I thinking about it few months already. I even found guys who working with ebikes who familiar with such devices, but no one interested to make it one copy at least without “a bottle of vodka” how we saying :sweat_smile:

@Larsb ans @Konstantin_Cunichin thanks for your pains

90

not even started yet. I’ve considered bringing it when we go to my mother in law for christmas, then i can do some winding therapy when needed :grinning:

5 Likes
91

Any news on the rewinding?

1 Like
92

Any Updates on rewinding?

93

How is the motor in general, whant to get one of this,