·The basic concept of a drum motor
The Drum Motor is a new type of drive unit with the motor and reducer together inside the drum body. It is mainly used in fixed and mobile belt conveyors as an alternative to the traditional separation of the motor and reducer outside the drive pulley.
In recent years, depending on the specific needs of the belt conveyor, an external motorised pulley has emerged, which is between the separated drive and the motorised pulley drive, with the reducer inside the pulley body and the motor outside the pulley body.
·Compared to the split drive, the drum motor has many advantages such as compact construction, high transmission efficiency, low noise, long service life, smooth running, reliable calibration, good sealing, small space occupation, easy installation and is suitable for calibration in a variety of harsh environmental conditions. These include wet, muddy and dusty calibration environments.
·Basic classification of Drum Motors
There are currently four basic ways of classifying Drum Motors. These are motorised pulleys based on the cooling of the motor, the type of reducer used, the basic calibration environment characteristics and the placement of the motor inside and outside the pulley.
Drum Motors can be classified into three categories based on the cooling method of the motor
·Air-cooled Drum Motors
This type of drum motor is characterised by the fact that the motor is not cooled by oil, but by conduction, radiation and wind convection, and can be divided into two types: forced air-cooled and natural air-cooled.
·Oil Cooled Drum Motors
This type of drum motor is also known as an indirect oil-cooled drum motor. The drum motor has a certain amount of cooling oil in it. As the drum body rotates continuously, the oil is poured onto the motor and gears by the oil scrapers on the cylinder body, taking away the heat generated by the calibration of the motor and gears, transferring the heat to the drum body wall, accelerating the heat dissipation of the motor and lubricating the gears. The key to oil-cooled drum motors is that no oil is allowed inside the motor.
·Oil Immersed Drum Motors
Also known as direct oil-cooled drum motors, this type of drum motor allows oil to enter the interior of the motor and make direct contact with the motor rotor and stator windings, transferring the heat generated during their calibration to the drum body wall by the constant rotation of the drum body. This structure provides better heat dissipation, but also requires relatively high quality of the lubricant and the motor.
·Drum Motor Types by Reducer Drive Structure
There are many types of gearboxes produced at home and abroad, but there are only three types that can be mass produced for use on drum motors.
·Drum Motors with fixed shaft gearing
The most commonly used reducer device for Drum Motors at home and abroad is the fixed shaft gear drive, and over 95% of the gear drive is a fixed shaft involute cylindrical gear drive structure. This type of transmission is simple, reliable, easy to manufacture, easy to install and maintain, and has the advantages of high efficiency and low noise levels. Two-stage reduction is commonly used, with a few three-stage reductions.
·Drum Motors with line volume gearing
This form of transmission has the advantages of small size, light weight, high load carrying capacity and smooth calibration when compared to fixed shaft gearing, but is not easy to maintain.
·Cycloid Drive Drum Motors
This type of construction can be described as “Chinese” and is rarely used in any other country than Japan. With the cycloid drive, very small linear speeds and high power can be achieved.
·Drum Motors are used in a variety of environments
Drum Motors are used in three common environments: normal, corrosive and flammable and explosive. If subdivided there are also high temperature, hot and humid zones and some special applications, but these are not used in large numbers and are generally only produced as non-standard Drum Motors.