Abstract: A battery-powered electric polisher for treating concrete has the operational form of a self-propelled riding trowel. A rigid frame mounts a pair of rotors that descend into contact with the concrete surface. Hydraulic tilting circuits for polisher steering control are activated with joysticks. An electrically driven hydraulic pump powers the tilting circuits. Each rotor drives a lower, circular drive ring comprising a plurality of spokes. Drive ring spokes are nested within rigid channels defined in a lower a support plate so that the latter is removable. A plurality of radially spaced-apart abrasion devices descend from the support plate into contact with the concrete surface.