DC Link (Choke) Induction Furnace : Reactor
Reactor is in fact an inductor applied to electric circuits for various aims like filtering, stabilizing a constant current supply and preventing sudden current surges. In steel industry, both AC and DC inductors are used.
AC Reactor:
AC reactors are not necessarily installed in the power circuit of the induction furnaces and may apply according to the initial design scheme. Reactors If used in induction furnace circuit, it will be in the single-phase configuration and usually in parallel with capacitor bank that will deploy capacitor energy when needed and complete resonance circuit.
DC Reactor:
Reactor, also called DC-link in fact connects the rectifier and inverter to provide a constant DC current source for inverter as an input. DC reactors are designed and installed with predefined inductance and power rating. Hence, Araz Trans Co. in order to cover costumer demands according to their desired plan or will offer its own designs resulted by combining and optimizing various configuration.
The main parameter for a DC reactor is its inductance. To have better coordination with other equipments, it is suggested to have the reactor with couple of taps to be applied with proper tap according to other parameters. This will offer a degree of freedom to change the tap considering operating parameters.
Reactor products by Araz Trans Co. are as below:
Inner Core &Helical Winding
Disadvantages: Being non-disassemble for maintenance while the coil or any part of the core down is the beiggest problem of this design and will disrupt the operation when having an issue.
Advantages: Having the least material and manufacturing expenditures.
Outer Core &Kasten Winding
Disadvantages: Being costly for its material in comparison to other schemes.
Advantages: Having total physical isolation between core and coil and consequently easy disassembly while encountering a problem in the core or coil is the most outstanding advantage of this configuration which is a great benefit helping the operator to continue the process as soon as possible specially having a spare coil to substitute.
Outer Core & Toroidal Winding
Disadvantages: Like inner-core with helical winding design and maybe more than that, total disassembly is needed to substitute failed parts which is a major weak point for this scheme for reactors of the induction furnaces.
Advantages: Using less amount of copper tubes (but using a bigger core to avoid saturation), the cross-section of the tubes can be chosen larger which help avoid coil failures duo to current surges and resulted heat that can lead in a hole and water leakage.
Inner Core & Kasten Winding
Disadvantages and advantages: During a failure this type should be disassembled (maybe partially) but duo to its cellular arrangement it is possible to have a spare coil to substitute when needed. From this perspective, this type will have more preference over inner-core with helical winding type but lower than the outer core with Kasten winding type.
On the other hand, having complicated coil architecture and hence higher manufacturing costs, this type will cost more than inner-core with helical winding design but less than outer-core with Kasten winding type.