[Ether]

Originally Posted by r691175002

This AXI motor doesn't list any curves but the peak current draw is 4000W and if I do the math with their minimum efficiency it will be ~2700W.
http://www.modelmotors.cz/index.php?...14&line= GOLD

They give you Kv and R, which is all you need to approximate the torque vs speed curve.

R=0.027 ohms, Kv=225rpm/volt = 23.56 (rad/sec)/volt

So at V=25 volts:

stall current Istall = V/R = 926 amps (WAY beyond the operating envelope)

stall torque Tstall = V/(R*Kv) = 39.3 Nm

no load speed FreeSpeed = V*Kv = 589 rad/sec

There's your torque vs speed curve (approx).


The spec says this motor can tolerate 110 amps for 20 seconds.

So, at I=110 amps:

torque = (I/Istall)*Tstall = 4.67 Nm

speed = (1-I/Istall)*FreeSpeed = 519 rad/sec

power = torque*speed = 2424 watts (for 20 seconds, before it burns up)

The brushed motor also runs at ~60% efficiency while the AXI can maintain 85%+.

At 110 amps and 25 volts, the AXI is drawing 110*25 = 2750 watts and putting out 2424 watts. That's an efficiency of 2424/2750 = 88%. And it can only do that for 20 seconds, according to the spec. At 85%, it will be less than 20 seconds.