Description Overview Only 3 units available (previously 4 available) These are 50 Hz (European spec) Specifications Can be used as 60 Hz, but requires installation of a gearbox In the case of the 620, they use it in 60 Hz at 1500 rpm using a multiplicator gear box (x 1.2) The alternator can be used in 60 Hz by doing a small modification on the AVR (voltage regulator) Information can be found by searching: Jenbacher (General Electric) 620-US spec sheet