Oil supply system with vacuum pump for transmission of drive system

A drive system, comprising:

• a load;
• a drive unit providing a driving power;
• a transmission connected between the drive unit and the load to convert the driving power provided by the drive unit and to supply the driving power to the load, the transmission including a transmission casing;
• a bearing casing housing a bearing for rotatably supporting a rotating shaft of at least one of the load, the drive unit, and the transmission;
• an oil supply system including:
• a first oil receptacle collecting oil from the transmission casing via a first oil return line;
• a second oil receptacle collecting oil from at least one of:
• the load, the drive unit, and the bearing casing, via at least one second oil return line;
• an oil supply line and an oil supply pump connected to at least one of the first oil receptacle and the second oil receptacle, the oil supply line and the oil supply pump supplying oil to the transmission casing and at least one of the load, the drive unit, and the bearing casing;
• a gas check valve in a first coupling line that fluidly couples the first oil receptacle to the second oil receptacle above a maximum fill level of both receptacles, the gas check valve operative by application of a pressure differential between the first oil receptacle and the second oil receptacle to prevent gas from flowing from the second oil receptacle to the first oil receptacle;
• and
• a vacuum pump operatively coupled to the first oil receptacle and the second oil receptacle for selectively generating the pressure differential between the first oil receptacle and the second oil receptacle, such that the vacuum pump generates a negative pressure inside the first oil receptacle and inside the transmission casing connected to the first oil receptacle via the first oil return line.