ElectricGod wrote: ↑
Jan 24 2020 9:40pm
Ohbse wrote: ↑
Jan 24 2020 8:12pm
ElectricGod wrote: ↑
Jan 18 2020 1:02pm
Watts = volts X amps
Battery watts = battery voltage X battery amps
Motor watts = battery voltage x phase amps
This is obviously very incorrect, phase amps x battery voltage would result in more power output than power input from the battery.
Torque is phase amps, if you want more 'kick' you need more phase amps. A 12f will not give you enough torque on a qs273.
Current drops as bemf of the motor increases until motor current reaches near zero as voltage available equals bemf. Fw extends this speed at the expense of additional current being required. This is speed range is limited by the bemf voltage exceeding the controller silicon limits.
Very incorrect? How about overly simplistic and close enough for people that don't want to read white papers or spend time understanding what's really going on.
I said phase amps increases torque. Not sure what your point is.
For people that like white papers...
Here's one about how Kv works:
A couple of basic articals on bEMF:
https://electronics.stackexchange.com/q ... r-in-motor
EG mate, this is why some people get annoyed with you from time to time. On your RV motor thread you've just had it explained by several people in no uncertain terms that the calculation bV x phA is meaningless/useless/erroneous, yet here you are defending it as somehow valid or useful, if but 'oversimplified'. Its not even that... It doesn't tell you anything about the system at hand. its not 'motor watts'... motor watts is either A, = battery watts (perhaps accounting for controller output efficiency), or B, = mechanical output power, NEITHER of which is related to or determined by bV x phA. phA gives a indication of torque, subject to things like saturation. bV gives an indication of max RPM with respect to a given motor. its only with the knowledge of bA that power of either the battery output/motor input, or the motor mechanical output can be determined... and none of these values are determined (nor any other value of worth) by multiplying bV with phA. Perhaps you can explain what you are trying to get a 'feel for' with this number your calculating, some of us might be able to point you in a better direction?
You may well see this as some kind of 'personal attack' mate, but its not - its constructive criticism of the errors in your understanding and knowledge, with a clear indication as to both why its in error, and how to fix/improve it. And its stated in an effort to head off spreading of further confusion on an already complicated/complex enough system. If your looking for a 'simplified' view / understanding of the system, this is simply not the way to do it, because as mentioned several times now, it doesn't bare any relation to how the system will behave.