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What is used to measure air gap?
Wire gauge
Filler gauge
Dial gauge
None
Filler gauge
A feeler gauge (often mispronounced as filler gauge) is a precision tool used to measure narrow gaps or clearances between two machine components. It consists of a set of thin steel blades of graduated thickness, allowing the user to determine the gap size by finding the blade that fits snugly within the space.
A feeler gauge (often mispronounced as filler gauge) is a precision tool used to measure narrow gaps or clearances between two machine components. It consists of a set of thin steel blades of graduated thickness, allowing the user to determine the gap size by finding the blade that fits snugly within the space.
GtotalтАЛ=тИСi=1nтАЛtiтАЛ тАФ Total gap measurement is the sum of the thicknesses tiтАЛ of the blades inserted.
The principle relies on mechanical interference. A set of precision-ground steel leaves is inserted into the gap; the correct gap size is identified when a specific blade (or a combination of blades) fits with a slight 'drag' or resistance, indicating the gap dimension corresponds to the stamped value on the gauge.
Used extensively in motor and generator assembly for checking stator-rotor air gap.
Blades are typically made of high-quality tempered steel.
Accuracy depends on the precision of the leaf thickness and user experience in 'feel'.
Must be cleaned and oiled to prevent corrosion which alters dimensions.
Highly portable and durable.
Extremely precise for small gaps (as low as 0.03 mm).
Easy to use in confined spaces.
Subjective result depending on user 'feel'.
Susceptible to wear and damage over time.
Time-consuming for non-standard or varying gaps.
Measuring spark plug gaps in IC engines.
Checking rotor-stator clearances in electrical machines.
Setting valve tappet clearances.
Aligning machine tool components.
In the context of electrical machines, checking the uniformity of the air gap around the circumference is critical to prevent unbalanced magnetic pull (UMP).
Option A (Wire gauge) is used for measuring the diameter of conductors. Option C (Dial gauge) is a displacement sensor used for surface flatness or vibration, not typically for internal air gaps.
B is correct тАФ A feeler gauge is the standard tool used to measure precise clearances and air gaps between mechanical or electrical components.
Always remember that in electrical machines, an uneven air gap leads to circulating currents and excessive vibration due to unbalanced magnetic pull; regular maintenance using a feeler gauge is mandatory.