YT518 Mica-Aramid Hybrid Paper
YT518 Mica-Aramid Hybrid Paper
Calendered aramid paper containing 50% mica particles. Excellent thermal stability and electrical strength — prevents premature failure under partial discharge, extreme temperature and electrical stress.
Priced per requirement — tell us grade, width, thickness and quantity and we quote against it.
Technical specifications
| Composition | Aramid paper with mica, typically around 50% mica content |
|---|---|
| Thermal class | Class H (180 °C) / Class R (220 °C) |
| Thickness range | 0.12–0.40 mm, typical |
| Purpose | Partial-discharge resistance under inverter-fed voltage stress |
| Form | Paper and tape, slit to width |
| Compliance | UL, CE, RoHS, REACH |
Typical values for this material class, given as a guide. The datasheet carries the property table, test methods and tolerances for the grade and is the governing document.
Overview
YT518 is calendered aramid paper with mica particles incorporated into the sheet — typically around half the composition. It exists to solve a problem that plain organic insulation cannot: sustained partial discharge.
Partial discharge erodes organic materials. In a machine fed from a variable-speed drive, the fast voltage edges produce discharge activity that a plain aramid paper will slowly be consumed by, ending in premature failure that looks like a manufacturing fault but is really a materials mismatch. Mica is inorganic and does not erode in the same way. Combining the two gives the handling of a paper with the discharge resistance of mica.
When plain aramid paper is not enough
Specify a mica hybrid where the insulation sees:
- Inverter or converter-fed supply with fast-rising voltage edges
- Voltage stress high enough to produce sustained partial discharge
- Long service intervals where slow erosion would not be caught until failure
For conventional sinusoidal supply at moderate stress, a plain calendered paper such as YT510 is usually the right and cheaper answer.
Key properties
- Around 50% mica content — inorganic resistance to partial discharge
- Continuous service at 180 °C (Class H), used to 220 °C
- Calendered finish for consistent thickness and handling
- High electrical strength combined with discharge endurance
- Thermally stable and dimensionally consistent
- Inherently flame resistant
Applications
Inverter-fed motors
Slot and phase insulation in variable-speed drives where PD activity is expected.
Traction machines
Rail and industrial traction motors fed from converters.
High-voltage windings
Machines where voltage stress produces sustained discharge.
Wind generation
Generators subject to converter-generated voltage stress and long maintenance intervals.
Standards and compliance
- UL recognised component — certification held by the manufacturer
- CE marked
- RoHS compliant
- REACH compliant
- Manufactured under ISO 9001:2015
Certificates of conformity and mill test certificates are supplied with each shipment. Third-party testing can be arranged on request where a specification demands independent verification.
Sizes, packing and supply
- Thickness: 0.12–0.40 mm, typical range
- Width: slit to requirement
- Form: reels and slit tape
Quality and inspection
Every consignment is inspected before shipment and supplied with its mill certificate. For repeat programmes we hold the approved specification on file so a reorder repeats a known outcome rather than reopening the conversation.
Frequently asked questions
What is partial discharge and why does it matter here?
Small electrical discharges within or at the surface of insulation, below full breakdown. They erode organic materials over time. Under inverter supply they occur repeatedly, so a plain organic paper can be consumed long before the machine's design life.
Do I need a mica hybrid for a standard mains-fed motor?
Usually not. Plain calendered aramid paper is normally appropriate for sinusoidal supply at moderate stress. The hybrid earns its cost under converter supply or high stress.
Does the mica make it brittle?
It is less formable than a plain paper, which is the trade for the discharge resistance. For tight forming, discuss the geometry with us before specifying.
How much mica is in it?
Typically around 50%. The datasheet states the figure for the grade.
Can it be supplied as tape?
Yes — slit to width. YT-CM is the dedicated tape product if that is what you need.
Related products
Next step
Tell us the size and quantity
Send the thickness, slit width and annual volume for https://aramidpapers.com/wp-content/themes/aramidpapers and we come back with a costed offer, a firm lead time and the mill certificate you will receive with it.