Series circuit is closely related to a series of control applied in refrigeration and ventilation systems. The control circuit is an electrical circuit that can control the electrical load in a system. If all the control devices are connected in series, then opening a contact switch or other control device that is in the circuit will open the circuit and stop the distribution of electrical current or electrical loading.
3:30 image shows an example application of series-parallel circuit that applied to domestic refrijerator. A combination of series and parallel circuits are used on electrical systems equipment refrijerator system that serves to keep the temperature as desired. Control devices connected in series with the equipment being controlled, namely an electric motor. The circuit protection device series also includes a system necessary to maintain the security of the operation of a component equipment.
Where it will stop the operation of the compressor in case of unsafe operating conditions. If there is a contact of a safety device opens, the compressor will open the electrical circuit and the compressor will stop working.
Safety devices must be connected in series to ensure that unsafe conditions will decide the load it protects.
3:30 image combination circuit on the Circuit Applications Motor Control