Bifilar And Trifilar Apparatus
Product Code : EL-AMLE-10616
Bifilar And Trifilar Apparatus (code EL-AMLE-10616) is a wall-mounted pendulum apparatus used to demonstrate a mathematical pendulum and to find the moment of inertia of a body from its oscillation period. A beam, a cylinder or a circular ring serves as the pendulum body; hung on two threads it swings purely translationally, and hung on three threads it performs torsional vibration. Clamping devices allow the thread length to be adjusted.
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Specifications
| Parameter | Detail |
|---|---|
| Mounting | Wall mounted |
| Use | Demonstrating the mathematical pendulum and determining moment of inertia experimentally |
| Pendulum bodies | Beam, cylinder or circular ring |
| Thread length | Adjustable using clamping devices |
| Bifilar suspension | |
| Threads | Two |
| Motion | Purely translational oscillation in a plane, without rotation |
| Demonstrates | Mathematical pendulum |
| Trifilar suspension | |
| Threads | Three |
| Motion | Torsional vibration of the pendulum body |
| Demonstrates | Moment of inertia in an experiment on a rotary pendulum |
| Evaluation | Moment of inertia calculated from the measured oscillation period, which varies with thread length |
| Supply | |
| Product code | EL-AMLE-10616 |
| Manufacturer | Engineering Lab Equipment, Ambala, Haryana, India |
What Is the Bifilar And Trifilar Apparatus Used For?
The moment of inertia of a body sets how strongly it resists changes in its rotation, and for a composite or awkward shape it is often easier to measure than to calculate. With the bifilar arrangement the student hangs the chosen body on two threads and shows that it swings like a mathematical pendulum. With the trifilar arrangement the body hangs on three threads and is turned slightly so that it oscillates about the vertical axis; the student times the oscillations, alters the thread length with the clamping devices to vary the period, and calculates the moment of inertia of the beam, cylinder or ring from the measured periods.
What to Specify When Ordering
- Quantity — the number of apparatus required.
Frequently Asked Questions
What is the difference between the bifilar and trifilar arrangements?
In the bifilar arrangement the body hangs on two threads and oscillates translationally in a plane without rotating. In the trifilar arrangement it hangs on three threads and is set into torsional vibration.
Which bodies can be used as the pendulum?
A beam, a cylinder or a circular ring can be fitted as the pendulum body, so results for bodies of different shape can be set side by side.
How is the moment of inertia worked out?
The oscillation period of the body in trifilar suspension is measured, and the moment of inertia is calculated from that period. The period itself can be changed by adjusting the thread length.
How is the thread length changed?
Clamping devices on the apparatus hold the threads and allow their length to be adjusted, which in turn changes the oscillation period of the suspended body.
What does the bifilar suspension demonstrate?
Because the body swings purely translationally on two threads without turning, it behaves as a mathematical pendulum, and this behaviour can be shown directly to a class.
OEM Manufacturer
Buyers of the Bifilar And Trifilar Apparatus deal directly with its maker, Engineering Lab Equipment (Engineering Labs Equipment Pvt Ltd), whose works are at Plot No. 43, Industrial Park, Sector 2, Growth Center, Saha, District Ambala, Haryana, India. The company designs, makes and tests applied mechanics apparatus for statics, friction, machines and mechanisms, supplies engineering colleges, polytechnics, technical training institutes and research laboratories in India and overseas, and builds to institution-specific requirements on request. Tender details are on the Tenders/OEM page.
Related Applied Mechanics Equipment
- Compound Pendulum — metallic rod pendulum with fitted metallic balls, pivoted at any point for period and frequency studies.
- Torsional Vibrational Apparatus — bench top torsion bar rig with up to 3 mass discs, speed-controlled exciter and oscillation sensors.
- Vibration of Spiral Spring Apparatus — wall-mounted spiral spring and sliding-weight rotating mass unit with 0 to 360° angle scale.
- Rotational Moment of Inertia Apparatus — three-string pendulum with photoelectric timing for moment of inertia and parallel axis theorem experiments.
See the full Applied Mechanics Lab Equipment range or all Mechanical Engineering Lab Equipment.
Request a Quote
For this and other applied mechanics lab equipment, schools and colleges can contact Engineering Lab Equipment, a manufacturer, supplier and exporter based in Ambala, India. Quotations are given on request: send the number of bifilar and trifilar units required and your delivery location through the contact page, or add the Bifilar And Trifilar Apparatus to the enquiry cart from this page.
Last updated: October 2026
