What causes shaft vibration?

What causes shaft vibration?

Vibration can be caused by one or more factors at any given time, the most common being imbalance, misalignment, wear and looseness. Misalignment /shaft runout – Vibration can result when machine shafts are out of line. Angular misalignment occurs when the axes of (for example) a motor and pump are not parallel.

What causes high axial vibration?

High axial readings generally indicate misalignment. The cause may be external, like coupling misalignment, or internal, like mechanical looseness or a bent shaft. Looseness may include a worn coupling, an oversized bearing housing, or with a sleeve bearing motor, excess bearing-to-shaft clearance.

How can vibration analysis help identify misalignment?

The diagnosis for shaft misalignment logically is indicated by abnormally high vibration levels at one and/or two times shaft rotational rate frequency — 1X and 2X.” Alternatively, higher amplitudes in both axes in the plane of rotation than axially would indicate rotor imbalance.

What are 4 causes for machinery vibration?

The four major causes of Machine Vibrations. In pumps, motors, and most other rotating equipment, the four most common faults or causes of abnormal vibrations are misalignments, looseness, imbalance, and bearing wear.

What is excessive vibration?

Vibration can cause changes in tendons, muscles, bones and joints, and can affect the nervous system. Collectively, these effects are known as Hand-Arm Vibration Syndrome (HAVS). Workers affected by HAVS commonly report: attacks of whitening (blanching) of one or more fingers when exposed to cold.

What happens if high level of vibration occurs?

Exposure to vibration could have a negative effect on the health of your employees. It could damage joints, muscles, circulation and sensory nerves. This could lead to considerable pain, time off or even disability.

How do you stop motor vibration?

An easy method to reduce vibration is to install a clean damper on the rear shaft of the motor. Clean dampers are basically hermetically sealed plastic cases with an inertia body packed with silicon gel. The extra inertia and silicon gel help absorb the vibration and provides a stable damping effect.

How do you check a propeller shaft alignment?

Two methods used for establishing the desired alignment are the gap and sag method and the bearing load measurement method. The alignment is checked during installation by a taut wire, a sighting telescope or a laser beam.

What causes high axial vibration with a bent shaft?

Too long or too short coupling spacers may cause high 3× which may be confused with misalignment. The author’s experience has shown this problem to produce a high 1× vibration also. A bent shaft produces high axial vibration.

How does vibration analysis can detect alignment problems?

“Typically a machine will be misaligned, to some degree, with a combination of angular and offset misalignment. Angular misalignment creates stronger axial vibration, mostly at the running speed, that is, 1X vibration, whereas offset misalignment generates mostly radial — some vertical and horizontal — vibration.”

When is radial vibration due to shaft misalignment?

Suspect misalignment when radial vibration at 2× shaft speed is 50 percent or more of shaft speed vibration. Misalignment can also produce several harmonics of running speed. These harmonics are produced when shaft movement is restricted and the waveform is clipped.

How to diagnose and fix inboard shaft vibration?

Alignment Steps: Lift the coupling into its proper position and check that the two faces of the coupling are roughly aligned left to right. Slip the raised ridge on one coupling face into its mating groove. Capt. Vincent Daniello Next, slip the raised ridge on one coupling face into its mating groove on the other face.

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