Vishwakarma Institute of Technology

Department of Mechanical Engineering

SY: 2024-2025: Semester IV
MD - ME2202 – Machine Design

Experiment 04: Journal Bearing Test

Aim:
1. To understand the working principle of Journal bearing.
2. To measure the pressure distribution and friction torque of journal bearing as a function of
radial load, speed and lubricant.
3. To study the effect of operating parameters like load speed viscosity on pressure distribution
and friction torque.

Equipment:
Journal bearing test rig TR 60

Journal diameter (mm) 40

L/D ratio 1
c/r ratio 0.01
Radial Load (N) 0 to 750

Speed (RPM) 150 to 2000

Power 1Phase, 50 Hz, 15 A, 0.75 KW

Motor specifications:
Sr no Part detail Range
1 AC induction motor 1Hp,1415rpm,50Hz,5A
2 Stepper motor drive IMS200-220A

Sensor specifications:
Part detail Specification
Speed Sensor Proximity sensor AP-8,
Range Min 150 rpm, max 2000 rpm
Least count 1 rpm
Accuracy (1± 1% measured speed) rpm
Frictional Type Strain gauge type
force Range Range Max 600Nmm
Least count Least count 0.1Nmm
Accuracy Accuracy (0.1± 1% measured value) Nmm
Pressure Sensor Model: APS038N
Range 1000 PSI

Soham Phadnis S.Y. – C Roll No – 08 PRN – 12310009

 Vishwakarma Institute of Technology
Department of Mechanical Engineering
SY: 2024-2025: Semester IV
MD - ME2202 – Machine Design

Least count 1kPa

Accuracy (1± 1% measured value) kPa
Normal load Manual by dead weights Dead weight: 35N, 1st load =2.33kg(35+2.33*9.81=150N)
and 4no’s of 3kg to apply in steps of 150N
Range 150- 750N

Theory:
Lubrication reduces friction between two surfaces (such as sliding surfaces of a bearing and a shaft) in
relative motion. It is typically categorized as boundary, mixed and hydrodynamic lubrication. When a
journal bearing operates under boundary lubrication, the sliding surfaces of the bearing and shaft are
practically in direct contact and friction is at its highest level. Lower friction levels are achieved
through the use of mixed lubrication, where the sliding surfaces are partially separated by the
lubricant, and of hydrodynamic lubrication, where the sliding surfaces are completely separated by the
lubricant.
In hydrodynamic lubrication hydrodynamic pressure in the lubricant keeps the sliding
surfaces of the bearing and shaft separated from each other. The hydrodynamic pressure is caused by
the sliding motion
Hydrodynamic principle:

The equipment consists of following assemblies:

1. Journal assembly: The journal is rotated by an A.C. motor through AC drive and belt. It is
housed inside a spindle belt and pulley arrangement.
2. Bearing assembly: Brass bearing of ratio 1: 1 is used. It has a narrow orifice inside bearing
which lets oil into pressure sensor.
3. Load assembly: A lever arrangement with arm ratio 1: 5 is provided for load bearing radially.
Soham Phadnis S.Y. – C Roll No – 08 PRN – 12310009
 Vishwakarma Institute of Technology
Department of Mechanical Engineering
SY: 2024-2025: Semester IV
MD - ME2202 – Machine Design

4. Controller: The controller consists of the pressure, torque angle, reducing on it.
5. Sensors: Pressure sensor is fixed to bearing to measure pressure at various points. It is controlled
to measure upto 1000 psi proximity sensors used for measuring RPM.

Experimental Setup Details:

Soham Phadnis S.Y. – C Roll No – 08 PRN – 12310009

 Vishwakarma Institute of Technology
Department of Mechanical Engineering
SY: 2024-2025: Semester IV
MD - ME2202 – Machine Design

Construction:
This test rig is designed to operate normally under hydrodynamic lubrication. The benefits of
a test rig experiment depend heavily on the characteristics of the bearing test apparatus. The following
requirements are provided on this bearing test apparatus: versatility, wide operating range,
applicability to true-scale experiments with realistic bearing loads, and advanced control and
measuring systems. Test rig consists of a frame, a bearing unit and loading, drive, lubrication, control
and measuring systems. The main components of the test rig are installed in the frame. The frame is
generally relatively rigid to avoid disturbing deformations and vibrations. The bearing unit consists of
the bearing, housing, shaft and supporting bearings. The housing in which the bearing is placed for
testing typically has a simplified cylindrical design. The loading system generates the bearing load.
On this test rig both dynamic and static loading is applied through a single pneumatic cylinder. The
drive system drives the shaft and consists of a power unit and a transmission unit. Because of
relatively low power losses in the bearings, high output from the driving unit is seldom required. A
0.75Kw Ac induction motor is used. Belt is used for the transmission for accurate rotational speed
control, the power unit is driven by a variable frequency drive, and voltage to motor is controlled to
decrease variation in rotational speed.

The lubrication system lubricates the bearing, it consists of a tank with bearing immersed
inside it, the control system controls the main operations of the test rig, and automated control
systems have been favored.

Working Procedure:
Prepare controller for test:
1) Switch ON power switch on controller, allow 2min for stabilization of electrical items, all display
show some default values
2) Initialize pressure and torque display values to zero

3) Press START push button switch on controller, slowly rotate the SET SPEED knob in clockwise
direction, journal starts rotating when speed required for test is attained, press STOP push button to
arrest spindle rotation

Setting PC for test:

1) Open WINDUCOM 2010 software on PC, if software is not installed follow procedure mentioned
in installation page.
2) Click on run continuously icon on top bar for activating software screen.

3) Click ACQUIRE on Status bar to open screen for conducting test.

Soham Phadnis S.Y. – C Roll No – 08 PRN – 12310009
 Vishwakarma Institute of Technology
Department of Mechanical Engineering
SY: 2024-2025: Semester IV
MD - ME2202 – Machine Design

4) Enter file name for storing data & fill in the remarks column with test parameters & oil used.

5) Click on START button to activate screen to receive data from controller.

Test start:
1) Initialize the pressure display and torque display on controller to zero
2) Press START push switch to begin journal rotation, when the speed is steady , slowly lower
the loading lever till the bearing on loading lever presses the test bearing outer dia
3) Place dead weights on loading pan to apply required load.
4) Now the tester is ready, press TEST START push button on the controller, the initial position
of pressure sensor is displayed on controller in Angle and indexing of test bearing begin.
5) After attaining 9° indexing position, the indexing pauses for a minute to acquire and display
the pressure value on controller.
6) On PC screen the pressure values at individual positions are displayed in Cartesian
coordinates. Change the scale of graph to view pressure shape properly.
7) After one minute indexing continues till the next step 19o is reached, pauses for one minute, this
cycle continues till indexing angle reach 179o, test stops (i.e. indexing and journal rotation stops)
8) Record the torque readings from the controller Frictional torque display.
9) The entire record of Pressure (in K Pascal) v/s angle (in deg) are saved JBDA file and
after completion of test viewed by clicking on compare file.
Precautions:
1. Do not allow test bearing temperature to exceed 125°C.
2. Temperature above 125 °C will damage Pressure sensors.
3. Do not apply load without spindle running
4. Inlet oil supply should be always is in ON position.
5. Do not rotate journal without oil inside tank.
6. In case of power failure or discontinuation of the test rotate the pressure sensor to home
position before starting the test.

Soham Phadnis S.Y. – C Roll No – 08 PRN – 12310009

 Vishwakarma Institute of Technology
Department of Mechanical Engineering
SY: 2024-2025: Semester IV
MD - ME2202 – Machine Design

Observation Table:
Load = 6.6 kg
arm: leverage ratio = 1: 5
RPM = 600
So actual load = 330 N
Angle (degree) Torque (N-mm) Pressure (psi)
90 1102
100 1102
110 1102
120 1102
130 1102
140 1102
150 1102
160 1102 90
170 1102 425
180 1102 748
190 1102 780
200 1102 575
210 1102 250
220 1102 40
230 1102
240 1102
250 1102
260 1102
270 1102

Soham Phadnis S.Y. – C Roll No – 08 PRN – 12310009

 Vishwakarma Institute of Technology
Department of Mechanical Engineering
SY: 2024-2025: Semester IV
MD - ME2202 – Machine Design

Results and Discussions:

1. Pressure and Angle

Cartesian plot
The same graph is shown in polar plot:

Polar plot

Soham Phadnis S.Y. – C Roll No – 08 PRN – 12310009

 Vishwakarma Institute of Technology
Department of Mechanical Engineering
SY: 2024-2025: Semester IV
MD - ME2202 – Machine Design

2. Effect of Load on Pressure Distribution

Load W = 600 N
Speed N=1000 RPM
Load W = 450 N

Lubricant=Castrol GTX 20W-50

Load W = 300 N

Load W = 150 N

Fig1. Influence of Load on Pressure Distribution

 The pressure distribution increased significantly as the applied load was increased
due to the reduction in lubricant film thickness.
 At lower loads, the pressure remained relatively stable as the lubricant
provided sufficient separation between the journal and bearing.
 At higher loads, peak pressures were observed at specific angles, particularly near
the maximum load application points.
 The highest recorded pressure occurred at 750N, demonstrating the direct relationship
between load and hydrodynamic pressure buildup, as increased force compresses the
lubricant film and generates higher internal pressure.

Soham Phadnis S.Y. – C Roll No – 08 PRN – 12310009

 Vishwakarma Institute of Technology
Department of Mechanical Engineering
SY: 2024-2025: Semester IV
MD - ME2202 – Machine Design

3. Effect of Speed on Pressure Distribution

Fig2. Influence of Speed on Pressure Distribution

 As speed increased, the pressure distribution showed an upward trend, confirming the
hydrodynamic effect of journal rotation.

 At moderate speeds, the pressure buildup remained relatively stable, indicating a well-
formed lubrication film.

 At higher speeds, pressure peaked significantly, as the rapid motion created

higher hydrodynamic lift, improving lubrication effectiveness.

 However, excessively high speeds could cause turbulence and uneven pressure
distribution, reducing lubrication efficiency and potentially leading to instability in
the bearing system.

Soham Phadnis S.Y. – C Roll No – 08 PRN – 12310009

 Vishwakarma Institute of Technology
Department of Mechanical Engineering
SY: 2024-2025: Semester IV
MD - ME2202 – Machine Design

4. Effect of Viscosity on Pressure Distribution

Fig3. Influence of Lubricant on Pressure Distribution

Castrol GTX 20W-50 can handle more pressure than servo 20W-50.

 Lubricants with higher viscosity, such as Castrol GTX 20W-50, provided better
pressure resistance compared to Servo 20W-50.
 The experiment demonstrated that high-viscosity oils maintain a thicker
lubrication film, reducing direct surface contact and minimizing wear.
 A higher viscosity lubricant helps distribute pressure more evenly across the
bearing surface, ensuring consistent performance under varying loads.
 The results indicate that lubricant selection is critical in minimizing wear and
enhancing bearing efficiency, particularly in applications where high loads and
speeds are encountered.

Soham Phadnis S.Y. – C Roll No – 08 PRN – 12310009

 Vishwakarma Institute of Technology
Department of Mechanical Engineering
SY: 2024-2025: Semester IV
MD - ME2202 – Machine Design

5. Effect of Speed on Peak Pressure

1400
Peak Pressure (kPa)

1300

Load = 450 N
1200
Lubricant = Servo 20W-50
1100

1000
400 600 800 1000 1200 1400 1600 1800 2000
Speed N (RPM)
Fig.4. Influence of Speed on Peak Pressure
 Peak pressure values increased with speed, reaching a maximum at around 2000
RPM, showing a strong correlation between journal rotation and pressure buildup.
 The relationship between speed and peak pressure was non-linear, with the highest
rate of increase occurring between 600 and 1500 RPM, as the lubrication film
developed more effectively.
 Beyond a certain speed, the increase in peak pressure slowed, likely due to
stabilization of the lubrication film, which prevented further drastic increases in
hydrodynamic pressure.

Soham Phadnis S.Y. – C Roll No – 08 PRN – 12310009

 Vishwakarma Institute of Technology
Department of Mechanical Engineering
SY: 2024-2025: Semester IV
MD - ME2202 – Machine Design

6. Effect of Load on Peak Pressure

2000

1500
Peak Pressure (kPa)

1000
Speed = 1000 RPM
500
Lubricant = Castrol GTX 20W-50

0
100 200 300 400 500 600 700 800
Load W (N)
Fig.5 Influence of Load on Peak Pressure
 As load increased, the peak pressure rose sharply, with the most significant jump
observed between 300N and 600N.
 Higher loads compressed the lubricant film, increasing the direct interaction between
journal and bearing surfaces, which in turn caused higher peak pressures.
 This suggests that excessive loads can lead to potential lubrication failure if not
managed properly, emphasizing the importance of load regulation in bearing
applications.

Soham Phadnis S.Y. – C Roll No – 08 PRN – 12310009

 Vishwakarma Institute of Technology
Department of Mechanical Engineering
SY: 2024-2025: Semester IV
MD - ME2202 – Machine Design

7. Effect of Load on Friction Torque

300
Frictional Torque (Nmm)

250

200
Speed N= 1000 RPM
150
Lubricant= Castrol GTX 20W-50

100

50
300 350 400 450 500 550 600 650 700 750
Load (N)
Fig. 6 Influence of Load on Frictional Torque

 Frictional torque increased proportionally with load, showing a clear linear

relationship due to greater resistance between the surfaces.
 The highest torque values were recorded at 750N, confirming that greater resistance
occurs at higher loads as the lubricant film becomes thinner and less effective.
 Proper lubrication helps to reduce friction, but excessive load can still lead to
increased energy losses, requiring careful monitoring in industrial applications.

Soham Phadnis S.Y. – C Roll No – 08 PRN – 12310009

 Vishwakarma Institute of Technology
Department of Mechanical Engineering
SY: 2024-2025: Semester IV
MD - ME2202 – Machine Design

8. Effect of Speed on Frictional Torque

400

350
Load W=450 N,
Frictional Torque (Nmm)

300
Lubricant = Servo 20W-50

250

200

150

100
400 600 800 1000 1200 1400 1600 1800 2000
Speed N (RPM)
Fig. 7 Influence of Speed on Frictional Torque

 Frictional torque initially increased with speed due to greater shear resistance in
the lubricant, but after a certain threshold, it stabilized as the lubrication film
became more effective.
 At very high speeds, the effect of lubrication helped to minimize surface
contact, reducing additional torque buildup and maintaining operational
efficiency.
 This behavior suggests that there is an optimal speed range where frictional losses
are minimized while still maintaining adequate lubrication, making speed regulation
crucial in preventing excessive wear.

Conclusion

This experiment confirmed that journal bearings operate based on hydrodynamic lubrication
principles, where pressure distribution and frictional torque depend on load, speed, and lubricant
viscosity. Increasing load and speed resulted in higher peak pressures and frictional torque,
emphasizing the need to balance these factors for optimal performance and longevity. High-viscosity
lubricants like Castrol GTX 20W-50 provided better pressure management, highlighting the
significance of proper lubricant selection in reducing wear and improving efficiency. The results
aligned with theoretical expectations, proving that lubrication and operational conditions play a
crucial role in bearing performance.

Overall, the experiment provided valuable insights into journal bearing behavior, aiding in
better design and maintenance strategies for practical applications, such as automotive and industrial
machinery.

Soham Phadnis S.Y. – C Roll No – 08 PRN – 12310009