Top 10 Yueqing Combined Transformer Manufacturers | BottomRace

Looking for combined transformer manufacturers in Yueqing? This guide profiles ten local companies that publish combined instrument-transformer or high-voltage metering-unit products and a Yueqing contact address. The selection covers dry-type and oil-immersed constructions, two-element and three-element metering, indoor and outdoor installations, and units associated with overhead lines, pole-mounted switches and distribution metering.

In this guide, “combined transformer” means a combined instrument transformer or high-voltage metering unit that brings current transformers, voltage transformers, fuses, secondary terminals and sometimes an enclosure together. It is not a combined power-transformer package or a compact substation. The buyer must define the system voltage, earthing, CT and PT ratios, accuracy classes, burdens, number of elements, fuse arrangement, metering scheme and installation method before quotations can be compared.

How this list was selected: Official company, product and contact pages were reviewed on 22 October 2026. The order is a research shortlist, not a quality, price, certification, export or “best” ranking. A published product category or address does not prove that BottomRace has audited every factory or that every model carries every approval. Confirm the legal entity, production site, exact model, current certificate and test scope before ordering.

Ten Yueqing combined transformer manufacturers to compare

Start with the metering scheme and the physical installation, then use the published product focus to build a first supplier group. For each candidate, ask whether the quoted scope is the instrument assembly alone or a complete metering box with secondary wiring and terminals.

Manufacturer profiles and questions to ask

Specify the complete combined metering unit

A combined unit can contain two or three instrument transformers, fuses, secondary wiring, a terminal block and an enclosure. Two suppliers may quote the same JLSZV or JLSZY model name while offering different ratios, classes, burdens, fuse types, terminal arrangements and enclosure dimensions. Send every candidate one technical schedule and require written deviations.

Do not compare combined units by model name alone. A JLSZV or JLSZY label can cover different CT ratios, PT ratios, numbers of elements, accuracy classes, burdens, fuses, winding connections and enclosure dimensions. Ask for the guaranteed values and the complete bill of materials in the quotation. For three-phase four-wire metering, confirm how the neutral current and phase voltages are measured, how the CT secondary circuits are earthed and how the meter is connected during testing.

For an outdoor pole-mounted unit, review the mounting bracket, lifting points, creepage distance, cable or overhead-line connections and access for replacing fuses. For an oil-immersed unit, ask about oil type, sealing, oil-level indication and the applicable routine tests. For a dry-type unit, ask about the casting or assembly process, partial-discharge control and the temperature and UV performance of the enclosure and insulation.

What to inspect during a combined-transformer factory visit

Arrange the visit after the supplier has answered the technical schedule and identified the production site for the exact model. A combined unit brings several components and interfaces into one assembly, so the visit should follow the complete unit from incoming materials to final wiring and test.

• Incoming materials: review the magnetic cores, winding wire, insulation, casting resin or oil, fuses, terminal blocks, wiring and enclosure materials, and how each batch is linked to the work order.
• CT and PT production: compare winding direction, core construction, ratio taps, insulation and winding connections with the approved drawings for both instrument transformers.
• Assembly: check the CT and PT positions, phase spacing, fuse mounting, earthing points, secondary wiring, terminal numbering, covers and enclosure sealing against the complete-unit drawing.
• Routine testing: review ratio and polarity checks for each core, insulation resistance, power-frequency withstand, accuracy and burden tests, and any partial-discharge test required for the selected insulation system.
• Complete-unit verification: confirm that testing covers the assembled unit, including secondary wiring and fuses where applicable, rather than only the individual CTs and VTs before assembly.
• Traceability and packing: verify the serial number, nameplate, test record, drawing revision and packing list. Check terminal covers, fuse spares, wiring diagrams and installation instructions before shipment.
• Type-test scope: confirm that the report identifies the offered model, ratings and production site, and that the current certificate or test scope covers the actual configuration being purchased.

BottomRace coordinates electrical sourcing and purchasing in Yueqing. Pro: $0 separate service fee; procurement service costs are included in the product quotation. Basic: 5% of product value, with a minimum service fee of $100, for your existing Yueqing suppliers. Compare our Pro and Basic services. For on-site meetings, see our factory visit services. The quotation confirms the scope, inspections, payment terms and any additional costs.

For related equipment, see our current-transformer manufacturer guide, voltage-transformer guide, power-transformer guide and distribution-box guide.

Questions combined-transformer buyers often ask

What is a combined transformer in this guide?

It is a combined instrument transformer or high-voltage metering unit that combines current transformers, voltage transformers, fuses, secondary terminals and sometimes an enclosure. It is used to provide metering or protection signals. It should not be confused with a combined power-transformer package, a prefabricated substation or a low-voltage distribution box.

How do I choose two-element or three-element construction?

The choice follows the phase and wire arrangement and the metering scheme. Two-element units are commonly used in certain three-phase three-wire systems, while three-element units suit three-phase four-wire arrangements. Confirm the connection diagram, the number of CTs and VTs, the neutral arrangement and the meter or relay inputs before selecting a model.

Is a combined unit simply a CT and PT in one box?

Not always. The scope can include fuses, secondary wiring, terminal blocks, test links, an enclosure, locks and mounting accessories. Ask for a bill of materials and a complete outline and wiring drawing. A low price may exclude the metering box, fuses, terminal block or testing of the assembled unit.

Which accuracy class should I specify?

The class depends on the metering or protection requirement, the connected burden and the applicable utility or project standard. Specify the CT and PT classes separately, then ask the supplier to confirm the combined error at the actual burden. Do not assume that two components with the same nominal class will automatically meet the complete installation requirement.

Why does the fuse arrangement matter?

The fuses protect the voltage-transformer circuit and must match the system voltage, fault level and installation. The type, current rating, breaking capacity, carrier, spare-fuse arrangement and mounting position all affect safety and maintenance. Confirm whether the fuses are included, who tests the complete assembly and how a blown fuse can be replaced safely.

Can BottomRace help arrange a Yueqing combined-transformer factory visit?

Yes. Email your system voltage, phase and wire arrangement, CT and PT ratios, accuracy classes, burdens, fuse requirements, metering-box scope and preferred dates to contact@bottomrace.com. We can agree the local coordination, interpretation and observation scope before arranging the visit. We do not replace your engineer’s metering or protection design review.