Semi Auto and your AEG

Have you ever noticed that even a perfectly shimmed AEG will get a “hot grip” (i.e. a hot motor) during extended periods of semi auto fire? Well there is a very complicated and mathematical reason why. When your motor first receives amperage or current it actually converts DC power into AC in the windings of the motor. When this happens, for about 1/5 – 1/10th of a second, the motor is an inductive load and not a resistive load. That means it is putting amperage and voltage “out of phase” and returning “dirty power” to your battery. While your motor is in an inductive state it is drawing about 30-50 amps depending on your shim job, mechanical load (or resistance), quality of motor, your motors ratio (armatures per turn) and battery cell type.

On the semi-auto setting you are hitting this inductive high every single time you pull the trigger. Since the inductive state is only the first 1/5 – 1/10th of a second of the motors’ run time, the full auto setting will hit the high amperage of the inductance and when the power in back in phase it becomes a regular resistive load meaning its only drawing  10-20 amps. Essentially you get more shots with less amperage. What does all this mean in layman’s terms? It means full auto is a lot easier on your AEG than semi-auto. It is also A LOT better for the battery, motor and trigger switch.

If you have dry cell batteries (NiCad, NiMih) and use mostly semi auto, your batteries will last about a year, or maybe two. They are not tolerant of high amperage draws and dirty power return. But they will last twice as long if not more if you use mostly full auto. Lipos don’t care about this, however.