I'm trying to calculate the stall current for a 12 V DC gear motor (919D1481):
No load speed = 15800 RPM
No load current = 0.52 A
Nominal speed = 13360 RPM
Nominal current = 2.85 A
Nominal torque = 154.4 g·cm
Stall torque = 1000 g·cm $$$$
\begin{align}
\Delta I &= 2.85\mathrm{A}-0.52\mathrm{A}\\
&=2.33\mathrm{A}
\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad
\end{align}
\begin{align}
\Delta\mathcal{T} &= 1000\mathrm{g·cm}-154.4\mathrm{g·cm}\\
&=845.6\mathrm{g·cm}
\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad
\end{align}
\begin{align}
I_{stall} &= \left(\frac{845.6\mathrm{g·cm}}{154.4\mathrm{g·cm}}\right)*2.33\mathrm{A}\\
&=12.76\mathrm{A}
\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad
\end{align}
Can you tell me if this is correct?
Thanks.
Best Answer
It looks about right.
For a crosscheck, see the rest of the datasheet for winding resistance R (or measure several times, rotating the shaft very slowly to find the minimum brush resistance) then I(stall) = V/R.