I Inductive heating and eddy currents

Click For Summary
The discussion centers on a project involving inductive heating using two coils to melt lead in a rotary ceramic disc mold. Key questions include the effectiveness of iron core versus air core coils for focusing magnetic fields and whether inductive heating can occur when the part is not inside the coil. Participants emphasize the importance of coil configuration and phase alignment to generate effective eddy currents, suggesting that both coils should work in tandem to create a consistent magnetic field. Concerns about efficiency and electromagnetic interference are raised, with suggestions for using ferrite cores and resonant tuning for optimal performance. The conversation highlights the complexity of designing the system to ensure uniform heating across different mold shapes and sizes.
  • #61
artis said:
You need to look at the energy put in over time.
I did exactly that.
dB/dt * time = some J

Look at B in cos function
There are 4 distinct quadrants (that last gify shows it)
0-90deg (Bmax to zero)
90-180 (zero to Bmax)
180-270 (Bmax to zero)
270-360 (zero to Bmax)

The zero point is where dB/dt is max, as shown in that last gify.

I evaluated only the 0-90deg in my math above.
0-90 has a dB/dt, or J value from eddy (in my example, J per 25usec)
The overall J in eddy per full one cycle of frequency is the 0-90 J * 4

The push-pull in DC is technically AC.

To get same Bmax you need 100A DC, or 70.7A ACRMS

My math should be correct.
 

Similar threads

Replies
2
Views
1K
Replies
6
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 10 ·
Replies
10
Views
3K
Replies
1
Views
1K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 0 ·
Replies
0
Views
895