# how the induction heating works in distance or is it even possible?

#### tls123

Joined Jan 31, 2021
2
Hi, im kind of wondering if the induction heating at distance can be possible,
like the coil and the work piece kept at distance gap(~10cm),will it work?

#### MrChips

Joined Oct 2, 2009
23,505
The induced magnetic field decreases as the square of the distance.
Hence the field at 10cm will be a 100 times lower than the field at 1cm and 10,000 times lower than the field at 1mm.

Joined Jan 15, 2015
5,934
I doubt at 10 cm you will get much energy. As MrChips points out the field drops with the square of the distance. I have annealed brass at a distance of about 1 cm and that was with considerable current in my coil. Maybe 40 amps as I can't recall.

Ron

#### tls123

Joined Jan 31, 2021
2
The above principle ("the field drops with the square the distance") ,is it same for under vaccum condition?

#### MrChips

Joined Oct 2, 2009
23,505
Magnetic fields work in vacuum.

#### BobTPH

Joined Jun 5, 2013
3,306
The induced magnetic field decreases as the square of the distance.
Hence the field at 10cm will be a 100 times lower than the field at 1cm and 10,000 times lower than the field at 1mm.
Actually, this is only true for a point source, of which there are none for magnetic fields, or at large distances. At distances comparable to the size of the source, the field is much more complicated.

Bob