Elastic Shafts TM 625

Elastic Shafts

Type: TM 625
Name: Elastic Shafts
Technical Description

  The terms 'critical speeds' and 'resonance' are often used to talk about rotating systems. Resonance occurs when the natural frequency and the excitation frequency match. The natural frequency of an oscillatory system is that frequency at which the system can oscillate with the associated natural mode after a single excitation. Operation at critical speed can lead to breakage and damage to the components of the system in high-speed rotating machinery. To prevent this, the system is operated well above or below the critical speed and quickly driven through the critical speed range. Structural changes, e.g. changes to rigidity, can cause the critical speed to change, meaning the operational requirements have to be adapted.
  The TM 625 experimental unit can be used to study the natural modes of various shafts. Illustrative experiments are used to explain resonance and supercritical or subcritical states of an oscillating system. Six shafts of different lengths and diameters are available. The shafts can be mounted on four self-aligning ball bearings and fitted with a mass to construct a Laval rotor. The axial positions are read on a scale mounted parallel to the shaft. A three-phase motor drives the shaft via a flexible coupling. The electronically regulated speed can be selected via two potentiometers and is continuously variable. It is displayed on a digital readout by a revolution counter.
  A transparent protective cover and safety bearings ensure safe operation.
  The TM 620.20 accessory provides measurement and evaluation software, including sensors, for data acquisition via PC.

  The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments.


Learning Objectives / Experiments

- investigation of a Laval rotor
  * critical speed
  * self-alignment
- natural modes on a shaft with continuous mass

  distribution with
  * different bearing intervals
  * different shaft diameters
  * different shaft lengths


* investigation of the natural modes on 6 shafts with

  continuous mass distribution and of the Laval shaft1
* optimal visibility and simultaneous protection

  thanks to transparent protective cover

Available accessories
TM 620.20 -- System for Data Acquisition
Alternative products
PT 500.10 -- Elastic Shaft Kit
TM 620 -- Bending Elasticity in Rotors

[1] experimental unit for determining critical speeds and investigation of the natural modes of a shaft
[2] 6 high-strength steel shafts
[3] up to 4 self-aligning ball bearings moveable to any point as the shaft mount
[4] a mass to construct a Laval rotor
[5] 3 safety bearings and transparent protective cover for safe operation
[6] 2 pre-selectable speed ranges, speed electronically regulated and infinitely adjustable
[7] digital speed indicator
[8] system for data acquisition including GUNT software and TM 620.20 sensors available as an option


Technical Data

6 rotor shafts
- D: 3mm, 6mm, 7mm
- L: 600mm, 900mm
- hardened steel
Mass, disc-shaped
- D: 80mm
- m: 965g
- hardened steel
- power: 0,25kW
- max. speed: 6000min-1
- speed electronically controlled
Shaft mount
- 2x self-aligning ball bearings
- 2x safety bearings

Measuring ranges
- speed: 0...6000min-1
- scale for measuring distance: 0...1000mm


Dimensions and Weight LxWxH: 1550x380x450mm
Weight: approx. 65kg Required for Operation 230V, 50/60Hz, 1 phase or 120V, 60Hz/CSA, 1 phase Scope of Delivery 1 experimental unit
6 shafts
1 set of tools
1 set of instructional material Order Details 040.62500  TM 625  Elastic Shafts