The modern equivalent of Soviet ЛЭШО is continuously transposed litz wire — in the ДИАДА line it is the grade Литц оПП1. We match a replacement for wires to TU 16.К80-03-89 (ЛЭШО, ЛЭЛО, ЛЭПКО, ЛЭПШД — Soviet litz-wire grades, TU 16.К80-03-89) with ДИАДА transposed litz wire rated to a thermal class of 200 °C and with rectangular forming. Suitable for new designs and for cases where the design documentation allows an equivalent.
Enter the marking from your old design documentation — the tool works with all 10 grades of TU 16.К80-03-89 (ЛЭШО, ЛЭЛО, ЛЭПКО, ЛЭШД, ЛЭЛД, ЛЭП, ЛЭПШД, ЛЭТЛО, ЛЭЛ, ЛЭНП). It decodes the grade, computes the copper cross-section from S = n·π·d²/4 and matches the closest standard ДИАДА transposed-litz-wire construction as a replacement.
A strand with class 155–200 °C enamel (polyesterimide, polyamide-imide) instead of the class 105 °C used in ЛЭШО to TU 16.К80-03-89. By the Arrhenius law, every +10 °C of thermal margin roughly doubles the insulation service life at the same operating temperature.
Winding-window fill of 85–90 % versus 70–75 % for round ЛЭШО. Smaller core dimensions and better heat distribution.
Stranded strand only, with the radial position of the wires changing — no parallel-laid construction under clause 1.3 of TU 16.К80-03-89. Estimate per the Dowell model for a typical multilayer winding (m = 5–10) at 50 kHz – 1 MHz: losses lower by 10–30 % at equal copper cross-section. More on the stranding substitution.
Batch certificate, declaration of conformity, military acceptance (ВП — government quality representative) with a note in the logbook for defense work. TU ДСГТ.685660.019, OKPD2 code — available.
Transposition reduces proximity-effect losses, so at equal winding losses a smaller copper cross-section is enough compared with round ЛЭШО at the same frequency. This saves copper and reduces core dimensions. We compute the exact AC-resistance-based replacement for your operating frequency.
Clause 1.3 of TU 16.К80-03-89 contains a caveat that is rarely noticed when ordering. It allows the strand of grades ЛЭШО, ЛЭЛО, ЛЭШД, ЛЭЛД and ЛЭПКО to be made from parallel-laid enamelled wires — up to 16 wires inclusive, diameter 0.05; 0.071 and 0.10 mm. With no stranding. With no transposition.
"By agreement with the customer, the conductive strand may be made… from parallel-laid enamelled wires." TU 16.К80-03-89, clause 1.3
The name Litzendraht itself is German for "braided wire." A strand without stranding violates the literal meaning of the letter "Л" in the grade and physically behaves as a solid strand of equivalent cross-section: it suppresses neither the skin effect nor the proximity effect. It is attractive to the manufacturer for process reasons — laying thin wires in parallel is noticeably cheaper than stranding. It is invisible to the buyer from the wire's appearance, but critical for coil Q.
16 enamelled wires lying in parallel. For a 50 Hz mains there is no difference; for an HF winding at 100–500 kHz the strand behaves as a solid wire of equivalent cross-section. It can be told apart from a stranded one only in cross-section.
Multi-stage transposed stranding of the 3-4-5-bundle type, changing the radial position of the wires. TU ДСГТ.685660.019 contains no parallel-laid caveat — every construction in every series is stranded.
If your design documentation allows an equivalent, or you are developing a new product, write one line into the supply specification: "stranded strand, not parallel-laid. Application of the clause 1.3 caveat of TU 16.К80-03-89 is not permitted." With our equivalents this requirement is met automatically by the TU itself. A detailed analysis of the loophole and a Q calculation.
The old 16.К80-03-89 family has nine grades that differ by covering. The ДИАДА design bureau has a single transposed-litz-wire line with a configurable covering. The mapping between them:
| 16.К80-03-89 | Serving construction | Equivalent to ДСГТ.685660.019ТУ |
|---|---|---|
| ЛЭП | no serving | Литц (ПЭ-155-М) |
| ЛЭШО | 1 layer of silk | Литц оПП1 (ПЭВоПП1-155-М) |
| ЛЭПШД | 2 layers of silk | Литц оПП2 (ПЭВоПП2-155-М) |
| ЛЭЛО | 1 layer of polyester | Литц оПП1 or Литц оА1 |
| ЛЭЛД | 2 layers of polyester | Литц оПП2 or Литц оА2 |
| ЛЭПКО | 1 layer of kapron | Литц оПП1 or Литц оА1 |
| ЛЭТЛО | polyester braid | Литц хПП or Литц хА |
| ЛЭНП | rectangular, no serving | ЛитцПр (ПЭ-Пр-155-М) |
The direct answer to "what replaces ЛЭШО" is Литц оПП1. A single-layer polypropylene fiber serving over a class F strand. Compared with the original ЛЭШО:
Polypropylene is easier to process than natural silk. It is also more resistant to oils and climate than the polyester used in the commercial version of ЛЭШО made at other plants.
The old TU is limited to fiber (natural silk, polyester, kapron) and a single polyester braid in ЛЭТЛО. No films and no extruded insulation. ДИАДА adds the following to fiber:
PET film. Smooth surface, low friction in the winding. Precision windings.
PTFE (fluoroplastic) film Ф-4ЭО. Up to 200 °C. Resistant to oils and most industrial media.
Polyimide film — the best breakdown rating. High-voltage transformers, space applications.
Extruded polyethylene over PTFE. Water-protected construction. Highly critical applications.
Resistant to oils, fuels and UV. Moving cable systems, cable carriers, robotic applications.
PTFE + polypropylene or Arselon aramid fiber. The electrical properties of films plus the mechanical protection of fiber.
From ЛЭШО you can build a functionally equivalent Литц оПП1. Or you can immediately cover tasks that ЛЭШО was never fit for: high-voltage windings, transformers in oil-filled enclosures, products for high humidity and aggressive media.
Besides the covering, the construction must be matched by strand count. Transposed litz wire has lower AC resistance at the same frequency for an equal copper cross-section, and its outer diameter is usually smaller thanks to tighter stranding. The table shows real standard items from the 0.1 mm series catalog:
| ЛЭШО marking | SCu, mm² | ДИАДА equivalent (0.1 mm series) | When to choose it |
|---|---|---|---|
| ЛЭШО 7×0.1 | 0.055 | 7×0.1 | If the operating temperature is above 90 °C |
| ЛЭШО 10×0.1 | 0.079 | 10×0.1 | Power transformers 50–200 kHz |
| ЛЭШО 20×0.1 | 0.157 | 20×0.1 | Inductors in inverters |
| ЛЭШО 49×0.1 | 0.385 | 49×0.1 | High-power HF windings, induction heating |
| ЛЭШО 100×0.1 | 0.785 | 100×0.1 | Power electronics from 1 kW |
| ЛЭШО 200×0.1 | 1.57 | 200×0.1 | Welding inverters, ultrasound |
The table is simplified: a "geometric" recalculation. For markings in other series (0.071 / 0.15 / 0.2 / 0.25 mm) and non-standard constructions, the ДИАДА design bureau develops a custom build to your specific requirements. More on ЛЭШО — in the article about marking, construction and limitations.
Send us the marking — we will send a price estimate within one business day.
The modern equivalent is continuously transposed litz wire — in the ДИАДА line, the grade Литц оПП1 (a class 155 °C strand under a single-layer polypropylene fiber serving). It is a current replacement for the whole TU 16.К80-03-89 family of old Soviet litz-wire grades (ЛЭШО, ЛЭЛО, ЛЭПКО, ЛЭПШД and the rest). Compared with the original, you get a thermal class of 155–200 °C instead of 105 °C, a genuinely stranded and transposed strand instead of the parallel-laid construction allowed by clause 1.3 of the old TU, and the option of rectangular forming. The specific construction is matched by strand count and diameter — use the tool above or send the marking.
The direct equivalent for ЛЭШО is Литц оПП1: transposed litz wire with a single-layer polypropylene fiber serving over a class 155 °C strand. Match the specific construction with the tool above — it decodes the marking, computes the copper cross-section from S = n·π·d²/4 and shows the closest standard ДИАДА item. For a double-layer serving — Литц оПП2; for a braid — Литц хПП; for a bare strand — Литц.
Minimum batch is from 30 meters, including prototypes. Lead time is up to 20 business days. We send a price estimate within one business day of receiving the specification.
If the bill of materials explicitly specifies ЛЭШО wire with its marking and a reference to TU 16.К80-03-89, the replacement requires a chief designer's decision, agreement with the government quality representative, and sometimes repeated qualification testing. In borderline cases ("ЛЭШО or equivalent") we prepare a written equivalence justification.
The marking (n×d), required thermal class (105 / 130 / 155 °C or higher), type of outer covering (fiber, film, braid), the coil's operating frequency, batch length, and your target schedule. An original batch certificate or a piece of the original wire speeds up matching.
Multi-stage transposition (3-4-5-bundle stranding) reduces proximity-effect losses. Per the Dowell model, for a typical multilayer winding (m = 5–10) at 50 kHz – 1 MHz the reduction is 10–30 % at equal copper cross-section — the exact value depends on the number of layers in the window and the operating frequency, and is matched to the specific winding. In addition: a thermal class of 155–200 °C versus 105 °C for ЛЭШО; rectangular forming adds +20 % winding-window fill; tight tolerances suit precision tasks such as Qi and SAE J2954.
ЛЭЛО differs from ЛЭШО only in the serving material: instead of natural silk it uses a single layer of polyester (lavsan) fiber. The strand construction and cross-sections in Table 1 of TU 16.К80-03-89 are the same. In practice, catalogs often label as "ЛЭШО" wire whose serving is in fact ЛЭЛО (natural silk was long ago displaced by polyester). The direct equivalent for ЛЭЛО is Литц оПП1 (polypropylene, more uniform than lavsan and more oil-resistant) or Литц оА1 (polyamide, if compatibility with the traditional enamelling medium matters).
ЛЭПКО has a single-layer kapron (polyamide) serving. Thermal class A (105 °C), the same as ЛЭШО. The only difference from ЛЭШО is the fiber polymer: kapron is mechanically stronger and thermally more stable than natural silk, but is still limited to 105 °C. The equivalent for an existing specification is Литц оА1; if you need to raise the operating temperature to 155 °C — Литц оПП1 or film constructions.
Clause 1.3 of TU 16.К80-03-89 allows, by agreement with the customer, the strand of grades ЛЭШО, ЛЭЛО, ЛЭШД, ЛЭЛД and ЛЭПКО (wire count up to 16, diameter 0.05; 0.071; 0.10 mm) to be made from parallel-laid enamelled wires instead of stranding. With no transposition, no stranding into a bundle. Such a strand physically behaves as a solid wire of equivalent cross-section: it suppresses neither the skin effect nor the proximity effect. Coil Q at 200 kHz with such a strand is around 100–150 versus 400–500 for genuine stranded litz wire. It can be told apart from the stranded variant only in cross-section. Our TU ДСГТ.685660.019 has no such clause — in every construction the strand is stranded. When ordering from any supplier, specify explicitly: "stranded strand, not parallel-laid."
The price depends on the strand diameter, strand count, enamel and outer-covering type, and batch length. For a quote, send the marking and your target volume — we will send a commercial proposal within one business day.