Specialized Transformers and Inductors for Downhole Magnetics

Down Hole Magnetics

Being an industry-leading custom transformer and inductor manufacturer Custom Coils has built Downhole magnetics that fulfill our client needs. Over 50+ years of industry experience, we specialize in the design and manufacturing of downhole magnetics that can withstand extreme temperatures. Our transformers and inductors for downhole industry are designed to meet diverse specifications in shock vibration, size, and temperature.

Today, most of our downhole designs are for 200C and 220C although we have some that operate at 240C temperatures as well. As the downhole market continues to drill deeper, the operating temperatures have continued to increase.

Design Elements

The downhole industry, as with the aircraft industry, requires high reliability under extreme environments as a key element of the design. Custom Coils regularly delivers to customers who expect zero defects found. Materials used in downhole designs are very critical. Using the proper materials for the specific operating temperatures is imperative.

Hi-Temp Cores

  • Powdered Iron (200C)
  • MPP (200C)
  • Ferrite (300C)

Small Geometries

  • Toroids down to 4mm
  • EE5 ER9.5 E-cores
  • Potcores down to 7x4mm

Hi-Temp Wires

  • MW35-C (200C)
  • ML16 (240C)

Insulation Materials

  • Kapton (180C)
  • Teflon (200C)
  • Nomex (220C)
  • Teflon/GC (260C)

Flying Leads

  • Teflon type E

Solder Types

  • Lead-free (230C)
  • HMP (300C)


  • Ripley's 468-2FC (220C)
  • Dolph's BC346A (220C)

Related Products


Applications of Downhole Magnetics

Due to their beneficial features, downhole magnetics find their uses across industries. We regularly deliver inductors and transformers for the following downhole applications:

  • MWD (Measurements While Drilling)
  • LWD (Logging While Drilling)
  • Rotary Steerable Motors
  • Wireline
  • Completion Equipment

Inductors and transformers for the downhole industry are designed for tough environments and harsh conditions. At Custom Coils, we can design transformers for downhole industry that ensure not only protection from overheating, but can help improve the parts overall lifespan. For any queries, don’t hesitate to contact us at the earliest.

Have a question about a transformer or any other custom downhole magnetic assembly?

Ask our skilled experts can solve all your queries!

Contact Us At 605.934.2460


Custom Coils
PO Box 348
109 Iowa Street
Alcester, SD 57001-0348

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