When the windings of a transformer develop shorts, opens or other defects, the effective number of turns may change. This may result in the change of the ratio of the windings and affect the power conversion of the transformer. Ratio changes can cause severe power losses and instability in the electrical system. It is a good idea to regularly test the ratio of transformers to ensure efficient power conversion. Regular preventive maintenance also allows technicians to spot developing faults and stop them before they get out of hand.