We will discuss the wire wound resistor without inductance in this post. Wire wound resistor is made of coils. And all coils have some inductance. Then how inductance of the coils becomes zero in a wire wound resistor without inductance.
Wire wound resistor without inductance
A “Wire wound resistor without inductance”, We also call it a ” non-inductive wire wound resistor.
Wire wound resistor is made of coils. Further, all coils have some inductance.
However, in a few cases, we require a wire wound resistor without inductance. Then how inductance of the coils becomes zero in a wire wound resistor without inductance.
A wire wound resistor is made of a coil of wire over an insulation material.
All coils have a magnetic field inside coils, the direction of the magnetic field depends on the direction of the wire of the coil.
Now we take two coils put them one above the other and connect them in parallel. The direction of winding in each coil is reversed to each other. Then each coil will have have magnetic field in a different direction. This is because both the magnetic field will cancel each other.
Refer to Figure 1 above. The 2 coil windings are shown in red and green colour. The direction of the windings is opposite to each other.
The direction of the field is shown by red and Green arrows, depending on the current direction. Both arrows have opposite directions, so the net magnetic field is zero, Hence there will not be any inductance.
The result will be that, there will be no magnetic field inside the coil. So Resistor will not have any inductance.
However. the resistance will become half, due to parallel connections of the 2 coil wires.
If you like to watch videos then to get more knowledge please watch videos in Hindi and English both as you like:
Extra knowledge as per experience
In one of the projects (HVDC), we found that wire wound resistors were failing. They were wire wound resistors without inductance type.
Further, a failed resistor always has double the resistance of a good resistor value.
This was because, out of 2 coils, one coil was getting opened. So only one wire coil is left out of 2 parallel connected coils. So resistance became double.
I hope that you like reading an article on “What is wire wound resistor without inductance”
If you like this post then subscribe to my YouTube channel, G K Agrawal
Further read “AC or DC which is more dangerous”?
Further read “Which motor is used in the traction”
About the author – G K Agrawal B.Sc and B.Tech (from HBTU Kanpur), Retd. Sr DGM Design (BHEL), the inventor of patents, has lifelong industry experience in the electrical and electronics design field of R&D. He worked for BHEL. He shares his experience and knowledge on blogs and YouTube. Read the profile here.
