Recent content by ag123

thanks for your response ! i had a hard time initially figuring out how to connect the electrical analogs on the electric side to the physical mechanical side. so in the initial attempt i only modeled just the flywheel. then as i researched further on it turns out one of the 'easier' way to...

omg, i found that this little virtual flywheel inertia dynamometer actually is able to predict some things. the stall torque for my little motor is around 20 gf.cm ! how do i know? in my previous post the 2nd chart, there is a rather flatline portion on the torque v rpm graph reposted as...

the equation actually equates energy LHS is the electrical analogs of energy in each second, RHS is the physical mechanical (energy stored in spinning disc) and heat energy terms the i^2 . R term is easy to understand it is simply heat generated by resistance. i place the same on the right as...

the motor equation in this model is: $$ i^2 R + K i^2 \omega = { I \omega ^ 2 \over 2 } + \text{heat from coil resistance} + \text{heat from mechanical friction} \ldots ( 1 )$$ $$ \text{where i is current, R is resistance, K is the inductance of the motor!} \\ \omega \text{ angular...

i think the one of the roots for conservation of energy starts in the First law of thermodynamics "For a thermodynamic process without transfer of matter, the first law is often formulated $$\Delta U = Q - W$$ where ΔU denotes the change in the internal energy of a closed system, Q denotes the...

conservation of energy is true, you can simply consider the ideal gas law https://en.wikipedia.org/wiki/Ideal_gas_law if you consider adiabatic compression (i.e. all the energy is contained within the gas even if it is compressed) https://en.wikipedia.org/wiki/Adiabatic_process the equations...

the calcs are uploaded in the jupyter notebook https://www.kaggle.com/ag1235/flywheel shared publicly

if i use 6 ohm with the inductor starting model, the damage is drastic 60 rpm ! no more 7000 rpm lol efficiency? zero this isn't updated on line, it is just a sensitivity analysis

i found another mistake in my model, if i simply use 6 ohm as the motor winding resistance, in the model, rpm reaches 1000 rpm max, and the model is still not 'perfect' all that 1000 rpm is due to the assumption of Vin^2/R being transferred to the disc. i'd still need to fix the model. But the...

thanks russ, your tips helped ! i made some improvements in the model back emf = k . phi . w = k . i . w phi is the magnetic flux which is proportional to current, hence substituting current in place w ~ angular velocity k - back emf constant...

i'm basically wishing to calibrate some generic motors that are available out in the open that don't have specs. if one searches motor literature you would find various charts, these aren't the best ones but it shows the highly non-linear real curves of motor characteristics...

thanks all, would try those suggestions ;)

constant power is a simplifying assumption, and that is the initial model. the curves a consistent with spinning up the disc, the disc alone. The motor isn't considered, but the curves of reducing torque as rpm increase make sense, it is not really intuitive as the relationship is non-linear as...

mostly correct, but the chart in the 1st post show that the output torque may literally behave differently in the case of spinning up a disc (flywheel). Initially i start with a fixed output power assumption, i.e. that the motor is able to supply a fixed amount of output power to the disc. it...

well, i don't mean to argue, but this exercise is done in the hope to find a way to measure the *unspecified* (small) motors (inertia flywheel dynamometer), so there is no specs for the motor, this exercise is to derive the specs so that perhaps a later experiment can be done to get the missing...