Grin motor simulator figure iron losses?

[Hummina Shadeeba]

Is it possible to turn off wind resistance? The simulator is calculating iron losses but it gets lost in the wind resistance.

I’ve got a Motoped bike and it fits a hub motor as mid drive and I have two stators I can choose from.

18 tooth (16 or 20 magnets) 100x60mm

36 tooth (34 or 38 magnets) 100x60mm

Both have .2mm laminations.

I can fit maybe an 8:1 gear ratio from motor to wheel and I plan to do that. At 50mph or 4,500 rpm, with the 36 tooth stator, it’s 76,500 erpm. Is it better to choose a stator with the same dimensions but half the teeth and subsequent switching?


I’m looking for no-load testing of similar motors to extrapolate from




Other than the 36t motor being lighter and maybe smoother running why would it be worth choosing?

 

[Sturmey]

I dont know but I think you can make a sort of crude comparison of the iron/cogging losses with the simulator by setting them up with similar environment's and then clicking on and sliding the two vertical dotted line so that the motor power is showing zero and then reading off the battery power. I presume the battery power includes the controller power usage. In the example below, the larger Mac motor seems to use an extra 16W battery power at no load above the smaller mxus motor, both at 313.7 rpm which I assume would be expected. Both are geared so I assume there may be some type of gear losses as well as iron (and controller) losses modeled but I am not sure.

 

[Hummina Shadeeba]

I dont know but I think you can make a sort of crude comparison of the iron/cogging losses with the simulator by setting them up with similar environment's and then clicking on and sliding the two vertical dotted line so that the motor power is showing zero and then reading off the battery power. I presume the battery power includes the controller power usage. In the example below, the larger Mac motor seems to use an extra 16W battery power at no load above the smaller mxus motor, both at 313.7 rpm which I assume would be expected. Both are geared so I assume there may be some type of gear losses as well as iron (and controller) losses modeled but I am not sure.

View attachment 384755

there should be iron losses in both motors though and don’t think it’s revealing iron losses. Interesting result though.



In the drone world they don’t seem to care about iron losses as long as they get the power and cooling comes easily. Unless someone tells me differently, or I find a no-load test of a similar motor to extrapolate from that shows badly, I’ll go with the 36t stator and hugely expose the windings as they do.

Actually my 36 tooth stator seems to be .15mm laminations although I read thinner than .2 isn’t much better.

I’m wondering how insulated the laminations in all these motors are from each other and how it would effect eddies. they often don’t have any epoxy between lams and it’s easy to get a circuit from top to bottom of all stators. I’m going to vacuum in resin and see if can increase the resistance from top to bottom

 

[Sturmey]

Have you ever tried the 'Trip Simulator'. You can just use a horizontal line (or semi horizontal for hills/slope) instead of the map to get constant values under a set condition and it does show both the 'Core loss' and the 'Copper loss' separately. It also gives the motor parameters that they use for the different motors that they modeled.