Furnace transformer is used for changing voltage from high voltage input to a lower voltage output within its own furnace. These transformers are mainly used for industrial purposes.
Furnace transformers should supply very high currents, near to short-circuit currents, at reasonably low voltages in the steel melting and metallurgical industry.
Its capacity can be ranged from several hundred MVA through high LV currents, even more than 150 kA; and a wide secondary voltage range. Because of extreme LV currents, the OLTC is systematically placed on the HV side and the secondary load can be AC or DC.
How do they work?
These transformers have two voltage systems with the wiring. The primary one is the supply one and the secondary is the voltage.
Furnace transformers are designated by wider fluctuations and unbalanced conditions which result in voltage dropping, harmonics, etc.,
Because of the loading needs of the three phases, it needs voltage for every phase. These changes can be lowered by providing furnaces a high capacity and also to protect the secondary winding from the voltages of the primary winding.
Types of regulations available for furnace transformers:-
As for huge furnace operations, different HVAC transformers are used for regulating the voltage. It decreases the voltage to the primary winding.
It is used for medium and large furnace operations, in this, the booster transformer raises the output of the secondary voltage.
Flux voltage regulation:-It is also known as direct regulation. It is the usual regulation for the primary winding and also it is inexpensive for those who are thinking about economical conditions.
AC arc furnace transformers
They are specially made to overcome the problems of short circuits of the secondary voltage. Because currents in arc furnaces have wide fluctuations and imbalanced conditions.
DC arc furnace transformers:-
They are more specialized and have fewer disturbances in the voltage supply system.
For the optimal accomplishment, furnace reactors are used in the furnace tank for the better reactance value.
Reasons for the furnace transformer turn off:-
The following are the reasons for the turning off of the furnace transformer. They are -1.Bad controls
2.or there can be a loose wire. These are the major reasons for furnace transformers turning off.
In other cases, there can be a problem with the transformer. In that case, you have to replace the transformer.
If there’s a problem with the wires you can check them in this way:-
(i)Primarily, you have to know about the wires;
(ii) There will be two wires, one in black and the other in white;
(iii) You can check them by using a voltmeter;
(iv) Then, you should connect the black wire to the black and red or white wire to the white;
(v) Later, you will get the readings on the voltmeter according to the condition of the transformer.
Replacing a furnace transformer:-
When you have a faulted transformer you should replace it. Here’s how:-
(I) Make sure that you turn it off.
(II) Before replacing it check again at the circuit, whether you turned it off or not;
(III) Then you have to check for the transformer in the furnace;
(IV) Later, a wire cutter can be used for cutting the wires of the transformer;
(V) Now, you can place the new transformer to the wires as usual.
(VI) And finally, you have to check the voltage through a voltmeter.
Maintaining your Furnace Transformer
As we all know that we have to maintain things from time to time for their maintenance. So, even you have to check the furnace transformers for maintenance so that they run better for a long time.
In the maintenance, you have to check whether all the wires are fine or they can be loosened. You have to check them and fix them properly.
While coming to wires, knowing the wires is really important. In furnace transformers always the wires in the secondary windings get loosened. The colors of the wires are basically red and blue. Or in some cases, they can be red and white according to the manufacturer.
If there’s a problem with secondary voltage wires you can check them with the voltmeter. If the problem is with the transformer, you can replace it with the above-written procedure.
These are the things you need to know about a furnace transformer.