Ano, prehodit + a - a reverzace je vyresena.
Vykon lze bez problemu regulovat vstupnim napetim, ale nebejva to ta pozadovana funkce. Castej clovek chce regulovat otáčky a to pokud mozno pri maximalnim kroutaku. K cemuz je vymyslenej PWM regulator. Cinan ma za par susniku:
https://www.ebay.com/itm/12V-40V-10A-PWM-DC-Motor-Speed-Control-Switch-Controller-Volt-Regulator-Dimmer/312086658593?hash=item48a9d07e21:g:yawAAOSw8mRaqHON:rk:5:pf:0
A nebo na mensi, ale nejspis dostatecnej vykon:
https://www.ebay.com/itm/10-36V-DC-Motor-Speed-Controller-Reversible-PWM-Control-Forward-Reverse-switch/311136503903?_trkparms=aid%3D444000%26algo%3DSOI.DEFAULT%26ao%3D1%26asc%3D20170221122447%26meid%3D5e83821be4424194aa03223f211529d1%26pid%3D100752%26rk%3D2%26rkt%3D6%26mehot%3Dag%26sd%3D401087013386%26itm%3D311136503903&_trksid=p2047675.c100752.m1982 - i s prepinacem smeru