0011-4561 Studies of the permanent magnet dc machine Studies of the permanent magnet dc machine Bogusz Piotr author Korkosz Mariusz author Wygonik Piotr author Department of Electrodynamics and Electrical Machine Systems, Faculty of Electrical and Computer Engineering, Rzeszow University of Technology Faculty of Electrical and Computer Engineering, Rzeszow University of Technology Faculty of Mechanical Engineering and Aeronautics, Rzeszow University of Technology Correspondence to: Piotr Bogusz Correspondence to: Mariusz Korkosz Correspondence to: Piotr Wygonik 16 12 2015 Elektrotechnika Zeszyt 1-E (8) 2015 2015 151 160 Copyright © 2015 2015 <p style="text-align: justify;"> A hybrid drive of an unmanned aerial vehicle uses two mechanically coupled drives. In one of the drives, an electrical machine is used. Its role is not only limited to a motoring operation, e.g. during achieving the flight ceiling. The electric machine changes its operation into generating after reaching the flight ceiling, this allows not only meeting current electrical energy demands but also battery recharging. This paper presents the results of laboratory tests of a BLDC machine in motoring and generating operation. Mechanical characteristics of the motor for different supply voltages and external characteristics for generator were determined. The possible energy conversion efficiencies for both motoring and generating operations were determined.</p>