Ametek and Indiana DC motors Data (as generators)

Below is a comparison between the open volts and shorted amps for an Indiana 24vdc and an Ametek 30vdc. 

These numbers are showing that Indiana 24 makes a far better generator, generating always 1.8 times more open volts and 1.6 times more shorted amps than Ametek 30, at the same RPM.

Indiana 24 is making 14 volts at 229 RPM, while Ametek 30 needs 423 RPM to reach the same voltage.

Indiana 24vdc	Ametek 30vdc
RPM Volts   Amps  100  6.12 1.64   200  12.24  3.28  300  18.36  4.93  400  24.48  6.57  500  30.60  8.21  600  36.72  9.85  700  42.84  11.49 Reaches 14 Volts at 229 RPM	RPM Volts   Amps  100  3.36 1.00   200  6.71  2.00  300  10.07  3.00  400  13.24  3.95  500  16.60  4.88  600  19.92  5.85  700  23.24 6.83 Reaches 14volts at 423 RPM

Here is the graphical representation of the above numbers: