AC Adaptor?

[Al Skierkiewicz]

The series resistance of the motor is also complicated at startup with the inductance of the windings and the back EMF developed in the armature. The tough part about brush type motors is that generally, more than one winding is contacted by the brush assy. Due to this switching, the series resistance and inductance changes as the armature turns. I believe for testing the factory takes several readings and then takes the highest one for stall current. Series resistance is also affected by the shape and wear of the brushes and a variety of other factors. To measure the series resistance takes a device that will measure down into the fraction of an ohm range. A typical Fluke will not get you close to the actual resistance. At 100 amps at 12 volts, for example, the series resistance would be 0.12 ohms. (The contact resistance of the leads could affect a reading that low.)
It is possible to add capacitance to the output but there is a down side to that. The inrush current for the power supply goes up as you add to the output. That could pop the fuse or cause the supply to clamp for over current when you turn it on.
The best method of testing is a battery. You can breadboard a test setup using all of the electronics, breakers and the motors(sufficiently secured to the board) and check everything that way.