Reverse Engineering of a high Q tunable Inductor with Progressive Universal Winding 

Case Study

5 min read




Reverse Engineering

Leading provider of innovative instrumentation, critical sensor technologies, and advanced process control software.

To reverse engineer an obsolete high Q tunable inductor that uses progressive universal winding technique.

What is a high Q tunable inductor?

Electrical windings use electric currents going through a coil, to generate an electromagnetic field. An Inductor, also called a choke, is a passive electrical component consisting of a coil of wire which induces a magnetic field within its core as a result of current flowing through these coils. These components utilize different types of windings depending on their end application including progressive universal winding which is highlighted in this case study. Their design and manufacturing is a specialized process and different parameters are used to evaluate the performance of an inductor. One such parameter that is used is Q. The “Q” or quality factor is a measure of the damping of a resonant circuit or system. It is a dimensionless parameter that indicates the energy loss of a system as it oscillates at its resonant frequency. The system becomes more stable and efficient as its Q increases. This specific inductor utilized a tuning slug to vary its Q depending on characteristics of each circuit in which it was installed which enabled the engineers to optimize the performance of each device.

There are many different types of windings that are utilized in different magnetic components depending on their end use application. The style and size of each winding is highly dependent on the parameters and characteristics required for each circuit within which it is installed in. This holds true for highly specialized and unique machines where each magnetic component may have to be customized to ensure the highest performance of the end device.

Velatron Technologies brings decades of experience in designing and manufacturing custom windings. It was originally engaged in manufacturing radio and television coils since its founding in 1945 and during its early formative years. Today, the company’s capabilities extend to manufacturing transformers, inductors, and specialty windings for a large number of industries serving many applications.

Instrumentation devices and sensors, which measure and analyze are fine-tuned machines. Each component, including their windings, must be precisely engineered, and manufactured to ensure accurate readings. One of S.G. Smallwood Inc.’s recent customer is an industry leading provider of innovative instrumentation, critical sensor technologies, and advanced process control software.

The customer’s highly specialized devices are also used by NASA in their space programs. The coils that go into these sophisticated machines are used to generate the RF voltage which enables the devices to perform their end function. Unfortunately, their original supplier for these coils went out of business causing major issues for the OEM. 

The original inductor utilized progressive universal winding, laying the wires in a honeycomb pattern. This reduced the gaps, allowing for a higher fill factor and Q value. S.G. Smallwood Inc. was tasked with reverse engineering the inductor from samples that had been sent earlier.

Reverse Engineering Challenges

This request was challenging since it required reverse engineering on a component that was no longer in production and with obsolete raw materials. Other challenges included:

   Non-standard coil form diameter.

   Obsolete tuning slug.

   Finding an impregnation material that would not adversely affect the Q-factor.

   Classic Universal winding machines are obsolete.

Velatron Technologies Solution

From the sample provided, Velatron Technologies engineers were able to use that as a basis for the new design, which had to match (or exceed) the older one in performance, quality, and manufacturability. The reverse engineering process took place over the following steps:

Selected the nearest standard coil form diameter to eliminate machining costs.

Determined winding pattern (progressive universal winding) by analyzing the sample

Replicated the progressive universal winding pattern on the prototype

Used computerized numerical control equipment to ensure uniformity in all the windings.

Developed a new tuning slug in conjunction with the customer’s engineering team to replace the obsolete slug

“So glad that we found Velatron Technologies to be a part of our team. Great people to work with and their quality is second to none.”

Henry P, Electrical Engineering

Reverse Engineering That Gets Results

The new custom inductors were an effective replacement for the older units. Their performance matched the previous coils and enabled the customer to continue their product offering with minimal disruptions. Product lifecycle was also improved as the new custom inductors used raw materials that are readily available in North America for fast turnaround times.

This case study required Velatron Technologies to reverse engineer an obsolete coil that had been stopped abruptly due to the previous manufacturer going out of business.

Some key learnings from the project were:

Progressive universal windings are unique and require specialized equipment to replicate at mass scale.

Continuity of supply chain is very important to ensure enhanced product lifecycle through diversification of the supplier base.

Customer input is valuable in designing and validating components, especially the tuning slug.

We are one of the few manufacturers in North America that have the capability to universal wind and have done millions of units since our inception. If you are looking for help in magnetics whether it be product design, reverse engineering or build to print, contact us below.

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