Coil OHM changes after fixing hot spots

[Djamuras]

Hello,
I use serpent SMM RTA tank, and tank came with some 3mm coils, before i started removing hot spots coil meter [coil master Tab Mini V2 ohm meter) showed 0.12 ohm but once i removed all hot spots now it's on 0.26 ohm.
Is it normal? or i should throw that coil and start again?

P.S its my first RTA and actually first coil i work with

 

[speedfreek67]

Seems normal to me. The included coils are Nichrome N80 claptons, rated at 0.25 ohms. Nichrome can read low ohms until it is bedded in and the hot-spots removed.

 

[the_atomic_fart]

^exactly this.

 

[Djamuras]

Thanks guys

 

[Simon G]

what you call 'hot spots' are basically shorts I think, that's why they create a lower resistance.

 

[tootingyoda]

Yep normal as said. It's also a good idea to re check the screw tightness after dry burning. I often need to nip them up a touch.

 

[Djamuras]

Yep normal as said. It's also a good idea to re check the screw tightness after dry burning. I often need to nip them up a touch.

I did that first, that's was my first thoughts

 

[Tubbyengineer]

what you call 'hot spots' are basically shorts I think, that's why they create a lower resistance.

That's exactly what's happening, the "Hotspots" are areas of lower resistance - which is why they heat up faster, strumming the coil or spacing it breaks the short circuit between the wraps effectively increasing the resistance as there are no longer any shorted out wraps...

 

[Tubbyengineer]

I did that first, that's was my first thoughts

Do be careful though - overtightening causes it's own problems - stripped threads, Cam outs on the screw heads and in some cases you can just cut through the wire itself with the post screws...