Dash 8-100
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Less Severe
Flight Crew Rejected Takeoff; Flight Crew Returned To Gate; General Maintenance Action
Aircraft
During takeoff roll Auto-feather system did not arm.  Rejected takeoff; once clear of the runway and ATC advised of intentions contacted Dispatch and Maintenance. Conducted ground test of system per maintenance request; found no faults. MEL'ed as administrative control item. Reattempted take off and received same indication that the Auto-feather system did not arm.  Rejected second take off and returned to the gate. Contacted ATC; Operations and Dispatch.
Dash-8 Captain reported returning to the gate after failure of the auto-feather system was noted on the takeoff roll.