Drives and hydraulic aggregates are used in machine construction, raw material production, maritime and many other areas. In hydraulic systems oil transfers power and motion, in drives it’s a vital lubricant. Both as a power transfer medium and lubricant oil is heated by friction losses during operation. Since the viscosity of the oil changes along with the temperature, precise temperature stabilisation using oil/air coolers is a vital requirement for systems and drives for consistent power. The temperature further affects the ageing behaviour and the life of oils. To minimise the negative fluctuating oil flow has on the cooler design with varying ambient air temperatures, it’s wise to combine the cooler with a built-in circulation pump. The BNK series is characterised by efficient cooling matrixes, a compact, easy to maintain design and energy-efficient drive motors along with gerotor pumps.