Good point. I don't have to use aluminium. The case could even be CFC, as most of the heat will be lost through convection (hopefully).fechter said:Using stainless steel or titanium instead of aluminum makes a huge difference too.
Good point. I don't have to use aluminium. The case could even be CFC, as most of the heat will be lost through convection (hopefully).fechter said:Using stainless steel or titanium instead of aluminum makes a huge difference too.
I'm not sure it will make any difference, Ken. The fact that you're dividing the work between 3 controllers won't make any fundamental difference to the motor. The only advantage that I can see in this is for the controllers.kenkad said:I keep wondering 'if the torque constant is higher at lower phase currents', why are motors not designed so they have a multiple of 3-phase groups so that each 3-phase coil set is operating in the max range of 15-20 amps?
kenkad said:Regarding the recent torque constant vs phase current plots (model5d), I keep wondering 'if the torque constant is higher at lower phase currents', why are motors not designed so they have a multiple of 3-phase groups so that each 3-phase coil set is operating in the max range of 15-20 amps? Certainly, it seems that six 3-phase groups at 15 amps (90 amp equivalent) is much greater torque that one 3-phase group operating at 90 amps (seems like about 6 Nm vs 4.9 Nm on the last graph). Would this not also mean less concern about coil saturation, etc. Can someone provide an explaination? I cannot imagine more electronic losses with six 3-phase group of drivers. Just trying to understand what the simulation is showing.
bearing said:How is it possible for the Agni motor to have a completely linear torque/current relationship in it's full published current range?
http://agnimotors.com/95_Series_Performance_Graphs.pdf
Look at figures 2a/2b to get a picture of the copper/iron ratio. Is it enough iron to not even reach the start of saturation @ 400A?
http://www.google.com/patents/US20020163258
Is it possible to make brushless version with the same properties?fechter said:It's a brushed design, and each 'coil' has like one turn.
bearing said:Is it possible to make brushless version with the same properties?fechter said:It's a brushed design, and each 'coil' has like one turn.
Ill take ten!fechter said:bearing said:Is it possible to make brushless version with the same properties?fechter said:It's a brushed design, and each 'coil' has like one turn.
Yes, it is possible. The eCycle solid slot motor is an example. Each 'coil' is a single turn of solid copper bar.
The Remy HVH is another example. The datasheet is here:
http://www.remyinc.com/docs/Remy_HVH_250_Sep09.pdf
Miles said:Anyone an IEEE subscriber?
http://ieeexplore.ieee.org/Xplore/login.jsp?url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel4%2F5899%2F15803%2F00732255.pdf%3Farnumber%3D732255&authDecision=-203
bearing said:Interesting motors. But I still don't get why the "kt" is constant in the Agni, and has a significant slope in other motors. The Agni and the motors above has a special layout of the windings, but how the windings are layed out shouldn't have anything to do with saturation of iron. Using a solid conductor or 100 parallel insulated wires only affects fill factor.
fechter said:The flux in the iron is going to be a function of the amps x number of turns. If the number of turns is 1, it takes a lot of amps to saturate. The Agni also does not have 'teeth' on the iron that are more prone to saturation.
bearing said:fechter said:The flux in the iron is going to be a function of the amps x number of turns. If the number of turns is 1, it takes a lot of amps to saturate. The Agni also does not have 'teeth' on the iron that are more prone to saturation.
Makes perfect sense. I guess what I'm wondering is: what's the drawback? why isn't everyone making motors which doesn't saturate?