Critical Speed Investigation Apparatus & Accessories Model MT 021
Critical Speed Investigation Apparatus & Accessories Model MT 021
Sci-tech Critical Speed Investigation Apparatus Model 021 experimental unit teaches knowledge about how to determine the critical speeds. Illustrative experiments are used to explain resonance and supercritical or subcritical states of a vibrating system.
A three-phase motor drives a rotor shaft, onto which one or two masses may be fixed at various distances. The rotor shaft is mounted in two self-aligning ball bearings and connected to the motor 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. The position and distances to elements fixed onto the rotor shaft can be read on a scale mounted in parallel to the rotor shaft.
A transparent protective cover and safety bearing immediately next to the masses attached to the rotor shaft ensure safe operation.
| Size: | 95cm x 45cm x 55cm (LxWxH) |
| Weight: | 25 kg |
Item Description
Features
* Investigation of bending vibrations in rotors1
* Determining critical speeds1
* Position of rotor mount and rotating mass can be adjusted1
* Optimal visibility and simultaneous protection thanks to transparent protective cover
At a certain speed the imbalance forces of a rotating mass can cause part of the machine or the entire machine to vibrate in resonance with bending vibrations. This speed is known as the critical speed. The rotor and shaft on a motor or a turbine, for example, form a system that can resonate. In rapidly rotating machinery this state presents a danger because it can lead to breakage and damage to the components of the system. 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.
Sci-tech Critical Speed Investigation Apparatus Model 021 experimental unit teaches knowledge about how to determine the critical speeds. Illustrative experiments are used to explain resonance and supercritical or subcritical states of a vibrating system.
A three-phase motor drives a rotor shaft, onto which one or two masses may be fixed at various distances. The rotor shaft is mounted in two self-aligning ball bearings and connected to the motor 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. The position and distances to elements fixed onto the rotor shaft can be read on a scale mounted in parallel to the rotor shaft.
A transparent protective cover and safety bearing immediately next to the masses attached to the rotor shaft ensure safe operation.
Sci-tech Critical Speed Investigation Apparatus Model 021 accessory comes with optional measurement and evaluation software, including sensors, for data capture via PC.
The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments.
Technical Specifications
Specifications
[1] Investigation of bending vibrations and resonance of a rotating system
[2] Two self-aligning ball bearings moveable to any point as the rotor shaft mount
[3] Two masses that can be fixed at any point
[4] Safety bearing and transparent protective cover for safe operation
[5] Two pre-selectable speed ranges, speed electronically regulated and infinitely adjustable
[6] Digital speed indicator
[7] Options for data acquisition: either vibration sensors with supply unit for connection to an oscilloscope or data acquisition system including software and sensors
Technical Specifications
Three-phase motor
– power 0,25kW
– max. speed 3000min-1
Rotor shaft
– L=500mm
– D=6mm
– hardened steel
2x mass, disc-shaped
– m=965g
– D=80mm
– hardened steel
Shaft mount
– 2x self-aligning ball bearings
– 2x safety bearings
Measuring ranges
– speed: 300…3000min-1
– scale for measuring distance: 0…500mm
Optional
Vibration Sensors with Clamping
- Non-Contact Inductive Position Sensor, 2 cylindrical inductive linear sensors,
- Operating range 5…10mm, Reference distance 7.1…7.9mm, Sensitivity 1.6V/mm, Slew rate 1.5/ms, Frequency range 0…50Hz, Output signal 1…9V DC proportional,
- Fitted with 7-pole plug, fitted with clamping set, wrench span 36mm diam. x l: 30mm i.dia. x 60mm, approx. 0.25kg
Sensor Supply Module
- Benchtop unit to supply power and to condition measured data from inductive vibration sensors; analogue output signal voltage: 1…9V, output on 4mm laboratory sockets, signals are displayed on an oscilloscope
Oscilloscope
- 70Mhz Digital Storage Oscilloscope
Experiments
– investigation of bending vibrations and resonance of a rotating shaft
– determination of critical speeds with different arrangements of the bearing and masses on the rotor shaft
– investigation of the rotor shaft’s self-centering effect
Scope of Delivery
1 Experimental set up, complete
1 set of instructional material
Model Number
MT 021
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