Need help calculating coil size for inductive heater.

Thread Starter


Joined Sep 21, 2010
I need to heat up the tip of pieces of steel rods that are 15mm in diameter and 60mm long. I want to heat the top 14mm area of the tip of the shaft to about 600F degrees as quickly as possible without exceeding the capacity of my ZVS heater or power supply. I have an 1800W ZVS inductive heater and a power supply that puts out DC 53V, 25A. The ZVS unit came with a 52mm diameter 8 turn coil which is about 62mm tall.

I'm wondering if I can use a coil that is about 15mm tall to focus the energy only on the area that needs to be heated? If so, the coil would only be able to have 3 turns as the copper coil tubing used is 5mm diameter tubing. If that's fine, the next question is what should the internal diameter be for the coil? I believe the closer the steel rod is to the coil the more power it will use. I want it to heat quickly (about 10 seconds), but not draw more power than the capacity of the power supply or ZVS device. I'd like to keep the power usage down to about 1,000 - 1,250W to be on the safe side.

I found a calculator online that recommends inductive heaters for purchase and when I put in this data it recommended a 1000W heater unit. So I think I'm good with the gear I have as far as it's ability to do the job. I just don't want to do something stupid trying out other coil sizes and burn up the heater or power supply.