Dc Motor giving ac as well as dc voltage when used as generator

When I rotate the rod or the moving part of motor and probe its output through a multimeter (set on ac measuring) it shows around 0.50 volts.
When I set the multimeter on dc measuring, it still shows 0.50 volts. How is this this possible?.i have a mextech multimeter. When i slow the rotating of the motor the voltage falls in both the ac voltage and the dc voltage