Aircraft Electrical Systems (1) There are three basic types of DC motors; series, shunt, and compound. (2) In the series motor, the field windings, consisting of relatively few turns of heavy wire, are connected in series with the armature winding. Regarding the above statements, a. only No. 1 is true. b. only No. 2 is true. c. both No. 1 and No. 2 are true.