When induction Annealing

[kiwijohn]

So I have been annealing for a few years, and have gone from the long socket / drill method to induction annealing.
We all know that the case wall thickness effects the time, for heating ( even on the old method a longer flame time was required for lapua compared to winchester brass in the venerable .308).

And this has been very true for the timer set induction annealer based on the method employed in the Gina model as well.
My question is though why is there an amperage change? This is with a fixed voltage output, not some of the mods where a variable V and A can be applied.

I notice my Amps on a Lapua .308 case are around the 6.5 to 7 A in an anneal time of 5.4secs.

For Winchester cases a time of 3.4 secs reveals an amperage swing of 7.5 to 8A

I realise my overall times will be different from others but are other folk seeing this variation between brass brands?

 

[SGK]

The case in the work coil is part of the load on your induction unit. Yes, the conductivity of the case will affect the current draw of the induction unit (if not otherwise limited). You will also note that as the brass heats the current draw increases.

 

[kelbro]

Simple as pie!

The 'work' (watts or in this case, heat) being performed is a function of the voltage times the amperage. P=IxE.