This automatic voltage regulator is manufactured for three phase synchronous generators. They are designed to work with Marelli Motori generators with a size range of 160 – 500 frames. This regulator is manufactured to work on machines rated from 10 up to 2000 kVa. The automatic voltage regulator is fully insulated in order to maintain high reliability in severe ambient conditions. These include high levels of humidity as well as dust and a salt atmosphere. It is also suitable for high vibration levels. The unit has been made to protect equipment against damaging surges of power with surge suppression and has short circuit protection in the form of a circuit breaker. It reduces line noise and has phase to phase voltage balancing and also has harmonic filtering.
Technical specifications of the M40FA 640A Marelli Automatic Voltage Regulator
- Power supply voltage of 170 to 277 Volts at 50 or 60 Hertz
- Voltage sensing of 170 to 480 Volts
- Maximum continuative field current of 8 Amps
- Maximum forcing field current of 15 Amps for 1 minute forcing
- Field resistance of between 3.5 and 20 Ohms
- Operating temperature between -30 degrees Celsius and 70 degrees Celsius
- Weight of 670 grams
Characteristics and protection
There is an under frequency limiter and an over excitation limiter with a replaceable internal fuse. It has six potentiometers for easy use and adjustment. Output voltage of the generator can be adjusted in a wide range of between 200 and 560 Volts. It also allows for very fine adjustments. The frequency potentiometer is for changing the low speed protection corner frequency and is usually set at the factory in order to reduce the excitation when speed becomes lower than 90 of rated speed. The Amp potentiometer changes the over excitation limiter which protects the generator in case of over excitation due to load conditions which may damage the rotor. The stability potentiometer allows for easy stability setting. The slope potentiometer changes the low speed protection characteristic slope and sets the voltage droop for a fixed reduced speed. It also has an under frequency limiter for running at low speed.