SPECIAL 800NM 0.75kw ENGINE WITH CHAINS AND PINIONS. Gear motors for greenhouse vents. Engines are sold with a chain and pinion coupling kit. You can choose to mount the gearmotor on the side or mount it on a base. This may require a mounting plate (see related product). This motor can automate the movement of an overhead window, side windows, shading screens or even serve for the movement of automated doors. There are several references depending on the drive tubes and the chain coupling kit supplied (consult). This gearmotor would give us a movement capacity for an average window of up to 120m. This calculation is approximate and would depend on the type of installation or greenhouse that we have.