The rectified voltage generated by the alternator depends on the electrical load and the engine speed. A regulator system is required in order to supply the electrical loads with a constant voltage. The alternator voltage is normally controlled to values between 13.5 V and 14.5 V. Large changes in the current load of the alternator (major loads cutting in or out) can cause the voltage to temporary deviate from this range. These swings, however, must not exceed 1 s.