MM 320 UNIVERSAL VIBRATION APPARATUS
GENERAL DESCRIPTION

   This apparatus is used for studying a wide range of vibration experiments namely, pendulums, mass-spring, free andforcedvibration, lateral vibration, torsional vibration, vibration with and without damping.

    The apparatus consists of a basic unit for use with optional accessories for individual experiment.

TYPICAL EXPERIMENTS
LIST OF EXPERIMENTS (OPTIONAL)        
The following experiments are available. Only one experiment at a time can be carried out on the MM320-001 
Floor Standing Unit, MM320-005 Bench Top Unit or MM 320-007 Pendulum Unit.

.MM 320-010   Simple Pendulums.
This is for determination of period vs pendulum length.
Two spheres made of steel and wood are suspended on  cords from pins on a pendulum cross beam with knife edge support.

.MM 320-011   Compound Pendulum.
This is for determination of the center of gravity of the rod.
A round steel rod with an adjustable knife edge is suspended on a pendulum cross beam with knife edge support.

.MM 320-012  Reversible Pendulum (Kater Pendulum)
This is for determination of the acceleration due to gravity. 
It consists of a rod  with two adjustable knife edges and  a sliding cylindrical bob. It is to be suspended on a pendulum cross beam with knife edge support.

.MM 320-013   Bifilar Suspension.
This is for determination of the moment of inertia of an irregular shape object. 
A uniform bar is suspended by cords to the pendulum cross beam with knife edge support.  The bar is drilled at regular intervals along its length to carry two pegged masses. The radius of  gyration or moment of inertia of the bar assembly can be determined from the periodic time of torsional vibration.

.MM 320-014   Center of Percussion.
This is for determination of center of percussion. 
It consist of two pendulums supported by a pendulum cross beam with knife edge support. One pendulum is a light steel rod with a steel ball and an  adjustable knife edge. The other pendulum is a wooden compound pendulum with an adjustable steel weight and a knife edge. The length of the simple pendulum is adjusted  so that when allowed to swing and impact the compound pendulum, there is no lateral movement of the knife edge on   the flat support. The impact line on the compound pendulum is the line of center of percussion.  

.MM 320-020 Mass-spring Apparatus.
This is to demonstrate relation between vibration frequency, spring constant and mass.
A coil spring is suspended from a spring bracket attached to the top frame. Different masses are placed on a platform suspended from the lower end of the spring. Three different springs are provided. The platform rod is guided in a bushing to achieve a vertically free motion. The apparatus is equipped with a gauge to measure spring position.

.MM 320-030 Free Vibration Apparatus.
This is for determination of the natural frequency and amplitude of vibration with and without damping.
The apparatus consists of a beam hinged on a trunnion attached to the left vertical frame. The other end of the beam is attached on to a spring which is hung from a spring bracket. Near the end of the beam is a recording drum which hold a recording paper. A pen attached to the end of the beam provides a vibration trace on the recording paper. To ensure safety, a guide frame is provided to contain the beam vibration. Extra mass or a damper may be put on to the beam.

.MM 320-031 Forced Vibration Apparatus.
This is for a study of frequency ratio vs amplitude and phase angle.
The apparatus is the same as used in MM320-030 Free Vibration with an exciter motor attached to the beam. The exciter motor speed is variable and is shown on an indicator.  Two unbalanced rotors are attached to the exciter motor.  A synchronous belt connects the exciter motor to the unbalanced rotors thus providing a forced vibration when the motor runs.  Weights can be attached to the rotors. A damper is attached to the beam and a disc recorder with pen and holder is used for phase angel measurement. 

.MM 320-040 Lateral Vibration Apparatus.
This is for a study of the frequency ratio vs amplitude and phase angle.
The apparatus consists of a beam hinged on a trunnion attached to the left vertical frame. The right end of the beam is attached to two bearings which are free to move in a guide attached to the right vertical frame. An exciter motor is attached to the middle of the beam. Two unbalanced rotors are attached to  the exciter motor. A weight with its holder is attached to the unbalanced rotors. By running the exciter motor at a different speed, the beam natural frequency can be excited. Further experiments can be carried out by attaching a damper onto the beam. An electrical contactor is attached to  the beam and a micrometer is attached to the bottom frame beneath  the contactor. By adjusting the micrometer to be in contact with the electrical contactor, the amplitude of the vibration can be determined and at the same time the stroboscope is triggered such that the phase angle between the beam vibration and the exciter motor rotation can be determined.

.MM 320-050 Undamped Vibration Absorber.
This is to demonstrate vibration absorption by a double contilever system.
The vibration absorber consists of two masses clamped onto two spring steel cantilevers attached to the  exciter unit. The system frequency can be tuned by adjusting the masses along the spring cantilevers. The system can be  used to absorb and reduce the unbalanced force. 

 

. MM 320-060   Torsional Vibration Apparatus, single rotor system.
This is to determine the moment of inertia of a fly wheel and period of rotation.
A shaft is attached to a fixed chuck attached on the bottom frame. A compound rotor with a chuck is attached to an axle which in turn is attached to a vertical frame.The other end of the shaft is clamped to the rotor chuck which  is free to rotate.Three different diameter steel shafts are supplied.

.MM 320-061   Torsional Vibration Apparatus, two rotors system.
This is to determine vibration period and the node on the shaft for two rotors.
A single rotor and a compound rotor with axles  are attached on the left and right vertical frames. The rotors are free to rotate on the axles which are set at the same height. Each rotor has a chuck which can be clamped onto the same shaft. Three different diameter steel shafts are supplied.

.MM 320-062 Torsional Vibration Apparatus, single rotor with damping.
This is to measure damping coefficient and investigate the effect of oil depth.
For a damped torsional vibration, a vertical set up on one side of  the frame is required.A fixed chuck is attached to the top frame. The shaft passes through a removable nylon guide bush and is gripped by a rotor chuck at the lower end. Attached  to this rotor bottom is a cone for immersion into an oil reservoir beneath for damping. The oil reservoir level can be adjusted to vary the immersion, hence damping. An angular scale is attached to the rotor and angular displacement is indicated by a pointer.  Amplitude-time graph of vibration is obtained from a drum recorder on the rotor and a sliding pen. Three different diameter steel shafts are supplied.

OPTIONAL EQUIPMENT

. Learning software for the Universal Vibration Apparatus.

This software provides a simulation for actual experiments on the apparatus. It is an inexpensive means to learn about the subject for those who do not yet have the real equipment and it is also very useful for class introduction before proceeding to run the actual apparatus.

. MM320-150 Computer Interface

     Sensor(s) computer interface unit and software for computer interface for beam vibration torsional vibration or pendulum experiments.