Busbar, Transformer & Motor Insulation

All three are NEMA LI 1 glass-epoxy grades and the glass-epoxy line maps to them directly: NP510 (G10) is the general-purpose structural insulator; NP511 (FR4) adds the flammability listing (the dossier flags UL 94 V-0 for this family) and is the default where a listing is required; NP512 (G11) retains strength at elevated temperature. Specify G10 where no flame rating is needed, FR4 where one is, and G11 where the part runs hot under load. The dossier covers 1/32″ through 1/4″ sheet; verify per-grade values on the maker TDS. [7]

When tracking or arc exposure drives the spec. Durostone's TDS carries comparative tracking data per IEC 60112, electric strength per IEC 60243 (EPC 203 reports 16 kV/mm), thermal-endurance methods per IEC 60216, and UL 94 V-0 listings on the UPM grades, the qualification package for arc-chute parts and tracking-critical isolation plates in dusty or damp gear. Standard G10/FR4 stays the economical answer for clean, sheltered positions. [2]

Muscovite is the workhorse arc-rated mica: MV phase barriers, arc-chute liners, and HV winding insulation, in rigid FR plate, flexible sheet, tape, and paper forms. Phlogopite extends the temperature range for the hottest zones; the HP5J class holds roughly 700–800 °C continuous with higher short-term/peak capability toward 1000 °C per the supplier data.

Both are inorganic and non-carbonizing, which is the property that earns mica its price near arcs. Thin rigid mica is brittle: specify it laminated to a backing where assembly handling is rough, and H-O converts the lamination as one part.

By role: 410 is the standard grade for layer insulation, slot liners, and wraps (1–10 mil per the dossier); 414 is the high-density grade where stiffness and the heavier hand help (2–7.5 mil); 411 covers its own niche in the family; 464 is the meta/para blend; and 818 is the high-temperature pressboard for structural insulation. All serve 220 °C class systems under the IEC 60085 framing, with system qualification under UL 1446. Keep substitutions inside the qualified system class. [4]

Mechanically different answers to the same electrical question. Aramid paper folds, creases, and survives insertion against lamination edges, which is why it is the slot-liner standard; polyimide film carries more dielectric strength per mil but wants support at folds.

Where slot fill is the binding constraint, the converted answer is often both: a paper-film-paper lamination that H-O supplies as a single die-cut, creased part, pairing the film's dielectric strength with the paper's forming toughness. Frame slot geometry and crease orientation on the drawing.

When the design is compact and high-power and the film must carry mechanical as well as dielectric duty, or when the qualification package is the requirement. APTIV standard grades (50 micron class) report dielectric methods per ASTM D149/D150/D257 with tensile modulus classes from 2300 to 4500 MPa per TDS.

The XPI series adds what demanding insulation engineers ask for: IEC 60243 electric strength, IEC 60270 partial-discharge methods, IEC 60112 CTI, and UL 746B long-term evaluation on the TDS. For general wraps and barriers, polyimide remains the economical thin-film standard. [10]

Clearance is the shortest distance between two conductive parts through air; creepage is the shortest path between them along insulating surfaces. They fail differently: clearance flashes over in one event, creepage degrades progressively as contamination and humidity let leakage current carbonize a track. IEC 60664-1 tabulates required values for both from the working voltage, overvoltage category, pollution degree, and material group.

A phase barrier is creepage engineering: it forces the surface path around itself. Trace the real surface path in CAD, not the straight line. [1]

The comparative tracking index, per IEC 60112, ranks how well an insulating surface resists forming a carbonized conductive track under contamination and voltage. IEC 60664-1 sorts materials into groups by CTI (Group I at CTI ≥ 600 down to Group IIIb) and allows shorter creepage for higher groups at the same voltage and pollution degree.

That is the mechanism by which a tracking-resistant composite or an inorganic mica barrier buys back layout distance. Verify the CTI group of the actual grade on its TDS; it differs between grades of one family. [2]

It is the fire and thermal back-stop, not the primary dielectric. ManniGlas glass-fiber paper (1200/1900/1902/2000) is inorganic, carries UL 94 listings and ASTM C177 thermal data per its TDS, and sits behind windings and along hot faces where an organic paper would age out, containing heat and resisting flame while the electrical insulation does the dielectric work. Specify it behind the insulation system, by grade weight and handling per the TDS.

H-O converts. We take laminate sheet, mica plate, paper, and film from the material manufacturers and waterjet-cut, die-cut, CNC knife-cut, slit, and laminate them to your drawing; we do not press laminate or make paper in-house. What we do in Winsted, Connecticut is precision conversion: clean laminate edges with no heat-affected zone, creased and formed liners, mica bonded to backings, and material traceability with lot-code TDS records.

In most cases, yes. If your drawing calls out a laminate, mica, paper, or film by a brand part number, send it through the form and engineering will identify a comparable family from the lines we convert, matching on the spec-relevant properties: NEMA LI 1 grade, CTI group per IEC 60112, thermal class per IEC 60085, dielectric basis, and mechanical form.

We provide an industry cross-reference, not a guaranteed drop-in, and for insulation systems we flag when a substitution would leave the qualified UL 1446 system rather than silently swapping.

H-O is a die-cutter and converter, so every insulation part is made-to-order to your drawing, including samples and prototypes. We maintain working material relationships with the laminate, mica, paper, and film manufacturers for faster turnaround.

Samples typically ship in 3–5 business days for common configurations on materials we commonly convert. Standard production runs ship about 2 weeks after drawing approval, including waterjet-cut laminate and laminated configurations. Expedited service is available when timing is critical. MOQ varies by material and part; prototype quantities through full production runs are equally accepted. Send the drawing and quantity through the form below for a specific lead-time commitment with your quote.

Yes. Rewind work is recurring conversion: the same slot liners, wedges, separators, and layer insulation, cut to each machine's slot map and shipped to the bench. Send the slot dimensions or a worn sample part; engineering will match the original system's thermal class (not just its thickness), set up the die or CNC program, and hold it for repeat orders. Made-to-order with MOQ varying by material and part; the process strip above covers typical lead times.