Most DC motor contactors consist of how many sets of contacts?

• A. one
• B. two
• C. three
• D. four

Answer: (A)

When a DC motor is started or stopped, the heavy-duty task is switching the motor’s power path. That is accomplished with the main contacts. In a typical DC motor starter, you only need a single main contact set to make or break the motor circuit. Auxiliary contacts exist for control signaling or interlocks, but they don’t carry the motor current and aren’t counted among the main power contacts. Because most DC motor starters only need to switch one circuit, a single main set is the standard. More poles would be used only for more complex arrangements or reversing circuits, not for the common setup.