Key Takeaways
- EMS winding goods span custom medical transformer builds, high frequency transformers, toroidal coil winding, coaxial coil structures, and ignition-focused magneto coil winding services—delivered as turnkey electric assembly with testing and traceability.
- For clinical power systems, a medical transformer prioritizes creepage/clearance, reinforced insulation, leakage current control, and low EMI; encapsulation and overmoulding protect the winding pack in sterile or high-humidity environments.
- High frequency transformer designs (planar or ferrite) minimize losses via litz wire, interleaved windings, tight coupling, and low-profile cores—critical for compact SMPS and implant chargers.
- Different coil formats solve different problems: toroidal coil winding for low stray fields and efficiency; coaxial coil for reduced parasitics at RF; classic bobine self (FR term for inductor) for filtering and energy storage.
- Buyers often benchmark with search terms like “able coil & electronics.” Use capability checklists (materials, insulation system, test coverage) to compare EMS partners objectively.
From ventilators and patient monitors to EV chargers and rugged ignition systems, the right winding strategy determines thermal headroom, EMC performance, and lifetime reliability. This guide explains how EMS (Electronics Manufacturing Services) providers build medical transformer assemblies, high frequency transformer topologies, and specialty coils—including toroidal coil winding, coaxial coil, and magneto coil winding services—and how overmoulding and end-to-end electric assembly practices reduce field failures.
What Counts as “EMS Winding Goods”?
“Winding goods” are magnetic and inductive components delivered as finished subassemblies. Typical scope includes medical transformer and high frequency transformers, inductors (aka bobine self), chokes, coaxial coil structures, and ignition coils. An EMS partner builds and verifies these units, integrates leadframes or harnesses, performs overmoulding or potting if specified, and ships them ready for electric assembly on your line.
Medical Transformer: Safety by Design
A medical transformer isolates patient-applied or operator-accessible circuits. Core practices include reinforced insulation systems, controlled leakage current, adequate creepage and clearance, thermal class selection, and meticulous documentation. Potting or overmoulding protects windings from humidity and cleaning agents while damping vibration. Typical tests: hipot, partial discharge, temperature rise, leakage current, and full functional under load.
High Frequency Transformer (SMPS) Essentials
A high frequency transformer trades laminated steel for ferrite cores to operate efficiently at tens or hundreds of kilohertz. Interleaved windings reduce leakage inductance; litz wire combats skin effect; careful bobbin design (or PCB planar styles) manages creepage paths. For compact chargers and DC/DC converters, low profile high frequency transformers are often combined with potting cups or overmoulding for acoustics and robustness.
Coil Architectures: Toroidal, Coaxial & “Bobine Self”
- Toroidal coil winding: High efficiency, low stray field, and compact form factor. Ideal for low-noise power conditioning.
- Coaxial coil: Concentric conductors reduce parasitic capacitance and external fields—useful in RF coupling, sensors, and precision medical coils.
- Bobine self: (FR: inductor) A catch-all term for wound inductors used in filters, buck/boost stages, and energy storage.
Magneto Coil Winding Services
Ignition and flywheel systems need high turns counts, robust enamel, and vibration-resistant impregnation. Magneto coil winding services focus on thermal class, resin selection, secure terminations, and endurance testing (thermal cycling, surge, and vibration). For compact engines and tools, potting and overmoulding protect the coil from fuel, oil, and shock.
Overmoulding: Durability, EMC, and Cleanability
Overmoulding encapsulates the winding pack and terminals in a protective polymer. Benefits include moisture sealing, strain relief, improved acoustics, and consistent creepage paths. For medical and outdoor service, chemical-resistant materials and controlled molding profiles protect the electric assembly from fluids and shock.
Specification Quick-Start
| Item | What to Specify | Why It Matters |
|---|---|---|
| Core & format | EI/EE/EC, toroid, planar, ferrite grade | Losses, profile, stray field |
| Windings | Turns, wire (litz/round/foil), interleave, toroidal coil winding or coaxial coil | Coupling, copper loss, parasitics |
| Insulation | System class, tapes, bobbin/Basics, creepage/clearance | Safety, reliability |
| Encapsulation | Potting vs. overmoulding, resin type | Moisture, vibration, acoustics |
| Test plan | HiPot, surge, PD, Rdc, L/Q, temp-rise, EMC screens | Acceptance & traceability |
| Regulatory | Target end-standard (e.g., medical insulation rules) | Design rules from day one |
Comparing EMS Suppliers (Search Tips)
Engineers often search phrases like “able coil & electronics” to benchmark suppliers. Regardless of brand names, compare real capabilities: do they offer high frequency transformer expertise, toroidal coil winding, coaxial coil know-how, reliable magneto coil winding services, and in-house overmoulding? Ask for sample DFs, PPAP/FAI (if applicable), and a golden-sample with a documented test plan.
Buyer’s Checklist
- State application (e.g., medical transformer, charger, ignition) and electrical limits (V/A, frequency, regulation, temp rise).
- Define winding format (toroidal coil winding, planar, EI/EE, coaxial coil) and materials (wire, core, insulation).
- Choose encapsulation: potting vs. overmoulding; specify resin and environmental tests.
- List tests and documentation: HiPot/PD, L/Q, Rdc, surge, functional—plus labels, serialization, and CoC.
- Plan integration: leads, pins, or harness; PCB footprint; mounting; final electric assembly steps.
Frequently Asked Questions
Q1. What’s the difference between a power inductor and “bobine self”?
A: None—bobine self is a French term for an inductor. Both store energy and filter current ripple. The construction (toroid, drum, shielded) is chosen for EMI, footprint, and losses.
Q2. When should I pick a toroid over an EI/EE core?
A: Toroidal coil winding delivers higher efficiency and lower stray fields, great for low-noise supplies. EI/EE cores are easier to assemble and better when you need bobbins, multiple chambers, or segmented creepage distances.
Q3. Why use a coaxial coil?
A: A coaxial coil reduces external fields and parasitics, improving high-frequency behavior in sensors, wireless power, or RF coupling.
Q4. What advantages does overmoulding bring?
A: Overmoulding enhances environmental resistance, strain relief, vibration damping, and cleanliness. It also stabilizes creepage paths and can improve acoustics by reducing buzz.
Q5. Do you offer magneto coil winding services?
A: Yes—specify turns, wire gauge, thermal class, resin, expected surge/temperature profile, and any endurance tests needed for your ignition environment.
TPS Elektronik builds custom medical transformer assemblies, high frequency transformers, toroidal coil winding, coaxial coil solutions, and magneto coil winding services—including potting/overmoulding, serialization, and 100% electrical test for dependable electric assembly. Share your spec or send a sample for reverse-engineering.
