Drive through coupling. "D" arrangement :
The movement of the motor is transmitted to the fan by means of an elastic coupling. The impeller is fitted in a shaft that rotates on independent bearings or inside a strong bearing housing. This type of drive is recommended for continuous services and with hot gases.
Drive through pulleys and V-belts. "TVM" arrangement :
The use of pulleys and V-belts to drive a fan is recommended for all those applications in which the fan speed must be different to the motor speed. The motor is usually installed near the fan. Motor and fan casing have a common steel base.
Direct drive. "M" arrangement :
The impeller is directly mounted on the motor shaft. This is feasible when the fan is small in size, the required power is low and the fan rotation speed corresponds to the motor speed.