I have noticed there are a few designs for permanent magnet brushed DC motor, but I can't seem to find the benefits and downsides of either one. The first one (first attachment) uses three electromagnets placed on a triangular rotor. There are two arc permanent magnets on the outside. In this design, I believe only one magnet can get energized at a time, but the field created will be stronger than the ones in the design described below. The second one (second attachment) uses multiple electromagnets, separated, and placed on opposite ends of the rotor, and two regular permanent magnets placed adjacent to the energized coils. Assuming only one electromagnet get energized at a time, the electromagnet of each side will have a lower strength compared to the electromagnet of the design above, but there will be a force enacting on both sides. Using which design would be capable of producing a higher, more constant torque? Which would one be generally more efficient?