Series & Parallel combination QUESTION: How do load ratings change when contacts are connected in parallel or in series? Which option should be chosen? ANSWER: Series connection of contacts: A series connection of contacts allows a certain current even at increased voltage values (as stated in technical data of contactors). This is because the switching arc is divided into a certain amount of smaller arcs, depending on the actual amount of contacts in series. A series connection of contacts also strongly reduces contact erosion which means increased contact endurance. Series connection of contacts is used for DC-loads. Parallel connection of contacts: Since -due to mechanical tolerances- all contacts within one contactor never close or open simultaneously, a parallel connection of contacts neither increases the making capacity nor the breaking capacity of a contactor. The making- and breaking capacity of each contact is the upper limit also in this instance. Parallel connection of...