Motor wattage calculation.

[Generator]

I'm curious to know that how does this motor draws 9800w out of the battery pack? I'm not able to calculate that figure from given data.
Can anybody enlighten me?

Battery: 14 Cell / 51.8V
RPM: 150kv
Max current: 190A
Watts: 9800w
No load current: 51.8V/5.2A
Internal resistance: 0.011 ohm
Winding: 8T
Stator Pole: 24
Motor Pole: 20
Suggested ESC: 250A 14S Compatible

 

[johnjcbs]

51.8volts x 190amps = 9842 watts

 

[Generator]

Thank you John, Can't we use I square R formula here? I'm interested in watt calculation based on current only.

 

[johnjcbs]

Wattage =voltage x current
Here's a link for reference. http://www.rapidtables.com/convert/electric/Amp_to_Watt.htm

 

[amberwolf]

Brushed? Brushless? Number of phases?

If Ri is per-phase, then you'd double it across any two phases of a 3-phase brushless.

Then there is inductance, vs your controller's capabilities, for what current will actually flow initially vs continuously, etc. (low inductance is often what blows controllers up on higher powered EVs--look up "colossus" here on ES for some info on that).

Then there is BEMF, when under rotation.


Also remember that the watt rating of a motor is typically just a continuous rating that it could dissipate the waste heat from. You may well draw much more power htan that under load at startup from a stop, and much much less than that while cruising around.

The watt rating is not a literal amount of power the motor will always draw (unless you load it the same way they did to test it for that max power draw).

 

[Generator]

Brushed? Brushless? Number of phases?

draw).

Here is the link of internal pics of the motor: it only says internal resistance 0.011Ohm.

http://endless-sphere.com/forums/viewtopic.php?f=28&t=46813&p=690596&hilit=Turnigy+rotomax+150cc#p690596

I still don't understand how it works

 

[amberwolf]

That's a typical brushless 3-phase motor. If you're not sure how they work, there's a few places with good explanations. Some of the sticky threads in this subforum are a good place to start.

Knowing how the motors work will help you with your generator project, too, cuz essentially a motor and a generator are the same thing with opposite power flows, at the most basic level.

More advanced than that (getting into math stuff) and I don't really understand.

 

[Miles]

If Ri is per-phase, then you'd double it across any two phases of a 3-phase brushless.

Only for Wye termination, amber. Most "RC" motors are Delta terminated...

 

[Generator]

Only for Wye termination, amber. Most "RC" motors are Delta terminated...

Hi Miles I remember you had designed one motor. How was the output of that one? Which software you used to design it?

 

[Miles]

Hi Generator,

There's this one: http://www.endless-sphere.com/forums/viewtopic.php?p=847674#p847674

I can recommend Emetor, for motor simulation: https://www.emetor.com/

 

[Generator]

Just curious, let's assume this motor uses Magnets, which are X mm thick and gives equivalent of 150cc o/p. If we use 2 times X mm thick magnets [I know we will have to increase the diameter accordingly], won't it improve the output considerably for same input? May be we can get 200CC or 250CC or 300CC output?

 

[Miles]

So long as you realise that no energy is contributed by the magnets.......

 

[Generator]

So long as you realise that no energy is contributed by the magnets.......

I'm sorry, I didn't get it miles, can you explain in detail?

You see my knowledge is still in mW and your's in GW