Now plastic machinery, such as: wire drawing machine, blown film machine, granulating machine, injection molding machine, extruder, trigger, and so on many are using resistive heating mode, such as quartz tube heating coil, heating resistance wire, etc. This way of heating way is depend on the heat transfer heat transfer feeding tube for heating, in the process of heat transfer to lose part of quantity of heat, have to transfer to another part of heat to the air at the same time, also has caused a great loss of thermal energy, resistive heating mode heat energy utilization is lower than 60%, in other words, the resistive heating 40% of electricity is in doing this, wasting 40% of its electricity every month. Therefore, retrofit of the resistive heater significance is very significant.

Electromagnetic heater is according to the principle of electromagnetic induction, through internal rectification filter circuit of 50 hz alternating current into direct current, then through the PWM control circuit converts dc frequency for 20-30 KHZ high frequency high voltage, high speed change of current through the coil produces the changing magnetic field, when the magnetic field lines inside the magnetic field through the heated metal objects, can produce a myriad of small inside the heated metal eddy current, so that the heated metal object itself high fever. At the same time on the cylinder surface and covered them with a layer of insulation cotton, the heat generated by the air from the outside world, ran less than all but for the production of heat. Because electromagnetic heater heating mode is made heated objects (cylinder) their fever, and package the insulation cotton, package after the heat preservation cotton is not only the heat will not be wasted, more won't run into the air, so the electromagnetic heater heat faster, more energy efficient. Electromagnetic heater than resistive heating energy saving more than 30%.