This is a separately-excited automatic voltage regulator that provides closed loop control by sensing the alternator output voltage at the main stator windings. This adjusts the exciter stator field strength. The voltage induced in the exciter rotor is rectified by the rotating diodes. This magnetises the rotating main field which induces voltage in the main stator winding. The separately-excited automatic voltage regulator is independently powered by a separate permanent magnet generator which is mounted on the main alternator rotor shaft. Having a voltage level which is too high or too low can cause premature motor failure therefore it is imperative to have an automatic voltage regulator controlling the voltage output of the generator.
Design specification of the MX341 Stamford Automatic Voltage Regulator
This British made automatic voltage regulator has a sensing input of 190 to 264 VAC (volts alternating current) on single phase 2 wire at a frequency of 50 to 60 Hertz. The input power is 3 phase 3 wire with a voltage of 140 to 220 VAC. The current is 3 amps per phase and the frequency is between 100 and 120 Hertz. The maximum output voltage is 120 VDC (volts direct current) and the current is a continuous 2.7 amps or transient 6 amps for 10 seconds. The resistance is a minimum of 15 Ohms. Thermal drift is a mere 0.03 per 1 degree change in AVR ambient temperature.
Benefits and protection elements of MX341 Stamford Automatic Voltage Regulator
There is an under frequency protector which has a set point of 95 of maximum Hertz. This has been factory set and is semi sealed. The over voltage detection has a set point of 75 volts direct current with a time delay of 10 seconds. The operating temperature has a very wide range of -40 degrees Celsius to 70 degrees Celsius. It can tolerate relative humidity of 95 at 0 degrees Celsius up to 70 degrees Celsius. The storage temperature can vary from -55 degrees Celsius up to 80 degrees Celsius. This is not a range of operating temperatures but merely for storage.