Wiki article · Collection 03

Coil Insulation

Engineering reference on Coil Insulation for wireless power system design, integration, and deployment.

6 minArticle 32/50Coil Design

Coil Insulation — educational diagram — Fig.: Educational diagram for “Coil Insulation”.

Coil insulation spans strand enamel on magnet wire, inter-turn spacing, bobbin materials, and separation from ferrite and shields. Resonant receivers can develop kilovolt-class peaks on tuning capacitors and coil terminals even at modest battery voltage — insulation must be rated for peak AC stress plus transients from switching and plug events.

Mechanical abrasion during winding, potting shrinkage, and vibration in AGV service degrade insulation over time — design and test for life, not just Hi-Pot at birth.

01Material selection

Wire thermal class (180°C polyimide vs 155°C polyester) matched to thermal design.
Potting compounds with dielectric strength and CTI appropriate for environment.
Separator sheets between litz layers and ferrite where edge voltage concentrates.

Coil Insulation — supporting diagram — Fig.: Supporting illustration for “Coil Insulation”.

02Test

Hi-Pot between coil and shield at defined AC voltage with ramp rate. Partial discharge test for high-reliability programs. After thermal aging samples, repeat Hi-Pot to catch embrittled enamel.

03Failure indicators

Intermittent insulation breakdown shows as sudden Q drop or FOD false triggers.
Corona staining on potting near inner turns.
Moisture ingress in outdoor pads lowering insulation resistance.