International Journal of Control Science and Engineering 2012, 2(2): 16-18 DOI: 10.5923/j.control.20120202.03 Automatic Control of Temperature in a Shaft Bearing Musaab Hassan * , Alaa Alsadig Ali, Samah Izzeldeen Osman, Mai Kamil Saeed Department of Mechanical Engineering, Faculty of Engineering, Sudan University of Sciences and Technology, Southern Campus, Khartoum, Sudan Abstract There is a continuous need to keep the bearing temperature under a certain critical value. This can be achieved through lubrication. A continuous supply of lubricant is not a cost-effective solution. The aim of this work is to automatically control the temperature a shaft bearing. This is achieved by controlling the supply of the lubricant. The temperature is also sensed and sent to a monitoring terminal using wireless technology. Keywords Temperature Control, Microcontroller, Shaft Bearing, Lubrication, Wireless Technology 1. Introduction Shaft bearing get hot during operation and this will affect the life cycle of the bearing[1,2]. Temperature is considered as one important indicator about bearing life. Friction is one causes of temperature rise[3]. Rise in temperature can cause fatigue damage as well[4,5]. There are different products available in the market to lubricate shaft bearing[4,5]. A system proposed in[3] operates when bearing temperature varies more than 15℃, an alarm is activated and an LED indicator will light. There is also a need to monitor the temperature of the bearing and the operation can be restricted to certain temperature (e.g. 150 C)[6,7]. Lubrication must take place before shaft bearing reach its limiting temperature [6,8,9]. The sensor can be placed close to the bearing sur- face[6]. Different products incorporate automatic lubrication by controlling the amount of lubricant as well as the fre- quency[10-12]. Most of the proposed automatic lubrication control focuses on the amount of the required volume of lubricant besides the frequency at which the lubricant must be supplied. In this work, a different approach is adopted where the control action is based on the measured bearing temperature. In other words, the lubricant will only be ap- plied when the bearing temperature reaches a pre-set value. The control mode is programmed on-off type. 2. Description of the Mechanical System The layout of the mechanical system is shown in Figure.1. The mechanical system consists of a motor, shaft, bearing, oil tank, pump, and belt drive. The shaft is fitted into the bearing and it is made to rotate. The shaft is driven by the * Corresponding author: musaabh@hotmail.com (Musaab Hassan) Published online at http://journal.sapub.org/control Copyright © 2012 Scientific & Academic Publishing. All Rights Reserved motor through a belt. The rotation of the shaft causes a fric- tion between the shaft and its bearing. The resulting friction increases the temperature at the contact region. This tem- perature is to be measured by an appropriate sensor. The output signal of the sensor is connected to a control circuit. When the temperature reaches 58℃, the oil valve opens automatically to lubricate the frictional area so as to cool it down. The lubrication shall stop as soon as the temperature drops to a certain level (below 42℃) Figure 1. Picture of the mechanical system: (a) front view (b) side view 3. Electronic Design of the System The block diagram of the electronic design is shown in Figure.2. The temperature sensor (LM35) reads the tem- perature close to the frictional area and transfers the readings to the microcontroller (Atmega32). The signal received by the microcontroller is analogue so it will be converted to digital format through the ADC (Analogue Digital Converter) which is built in the microcontroller. The output of the first microcontroller is sent through two ports. The first port passes the temperature readings to the encoder (HT12E) and then to the transmitter (ASK module). The transmitter will send the signals wirelessly to the receiver (ASK module).