Micrometers

Micrometers

This topic has 2 replies, 3 voices, and was last updated 24 October 2023 at 01:06 by Howard Lewis.

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23 October 2023 at 17:06 #680855
martin h g bourn
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@martinhgbourn50370
How do you demagnitise an old micrometer that picks up steel filings?
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23 October 2023 at 18:08 #680889
bernard towers
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@bernardtowers37738
Find someone with a demagnetiser, where are you?
24 October 2023 at 01:06 #681011
Howard Lewis
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@howardlewis46836
If you can find an old motor with field coils, remove the rotor, and as long as the bore is large enough, it can be used a a demagnetiser.

Supplied with the correct AC voltage, tghe item to be demagnetised is passed through the bore.

The alternating magnetic field will decrease as the object leaves the device, so that the magnetism induced in the object also reduces to zero.

If you want to magnetise something, supplying a DC voltage to the field coils will magnetise the item.

BUT, since thedre will be no inductance with DC, the supply voltage should be lower.

For reasons of safety, I would not advocate using mains level DC voltage, for this.

To my mind, 48 volts would be as high as I would want to go

Howard
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