How are the NC contacts in a magnetic overload device connected?

The NC (Normally Closed) contacts in a magnetic overload device are connected in series with the control circuit to provide overcurrent protection. When the current flowing through the circuit exceeds a predetermined level, the magnetic overload device activates, opening its NC contacts. By being in series, this interruption effectively breaks the circuit, cutting off power and protecting the equipment from potential damage due to excessive current. This configuration ensures that when the overload condition occurs, the control circuit is immediately de-energized, preventing further operation until the circuit is reset.

Other connection options would not allow for effective protection. For instance, if the contacts were in parallel, the circuit would remain live even during an overload condition, defeating the purpose of the protective device. Directly connecting to the power supply or independently of the control circuit would also compromise the responsiveness required in an overload situation, as it would not control what's happening in the control circuit efficiently. Therefore, connecting NC contacts in series with the control circuit is the proper method to ensure effective operation of the magnetic overload protection.