Overview
A transformer feeding a rectifier or converter must be evaluated with the connected electronics, the supply network and the process duty. The transformer and converter are not interchangeable supply items. OSTL manufactures the transformer category; the scope of converter equipment, controls and integration must be agreed separately.
Separate the converter interface from the process output
A rectifier transformer quotation should identify the transformer’s AC-side duty and its relationship to the rectifier or converter. Process DC output alone is not the complete transformer specification. Provide the power-electronic supplier’s electrical schedule, operating cycle, loading, interface and any harmonic or thermal requirements it specifies.
Do not assume pulse number, phase shift, secondary arrangement, regulation method or harmonic capability. These are project inputs to be agreed, not catalogue promises. If an induction-furnace system includes a converter, coordinate its transformer boundary with the furnace duty enquiry.
Compare the whole converter-duty offer
Ask each proposed design to respond to the same duty, loss/reference conditions, winding, cooling and interface brief. Copper/aluminium choice or a nominal capacity cannot replace a complete technical schedule. Compare exclusions, drawing obligations, tests and supply boundaries before comparing commercial totals.
See steel and metal process questions, plant-network power transformers and control-panel interfaces. No process client, local installation or universal package is inferred from these application links.
Typical applications and industries
The following are general duty contexts to discuss, not a list of OSTL customer installations or a guarantee of suitability for every site.
- DC process supplies, such as electrochemical or metal-treatment systems, where the process designer specifies the converter arrangement.
- Industrial drive and power-electronic installations needing a defined transformer interface.
- Converter-fed heating and other process loads where harmonic and thermal duty need review.
- Industrial and process-sector projects with a documented rectifier or converter specification.
Define the operating duty
Send the converter supplier’s data, input/output arrangement, harmonic spectrum or study requirements, pulse/phase arrangement where specified, operating cycle and required isolation/earthing interfaces. Do not assume a particular pulse number, winding arrangement or harmonic performance from the product name.
General construction considerations
These are design topics, not fixed features promised for every supplied unit. Confirm the construction in the project-specific offer.
- Winding connections and any phase-shift requirement defined for the converter system.
- Thermal and loss evaluation using the specified loading and waveform information.
- Core, insulation, cooling and terminals coordinated with the installation requirements.
- Protection interfaces and any electrostatic screen or monitoring requirement considered only where specified.
Ratings and scope
For these duty-specific products, ratings as per project requirement. The exact kVA/MVA, voltage, construction and operating limits require confirmation in the technical offer. OSTL’s overall power and distribution transformer range is up to 10 MVA and up to 66 kV; dry-type transformers are manufactured up to 3 MVA. These overall ceilings are not a confirmed rating schedule for every special-duty product, and 66 kV must not be applied to dry-type equipment.
BIS, ISO and project-specific documentation
OSTL has held BIS licences in all five major transformer categories since 2020. This is a company credential, not a blanket BIS certification claim for this product line. Ask for the exact licence scope and the standards and documentation applicable to the proposed equipment.
OSTL is ISO 9001:2015, ISO 14001:2015 and ISO 45001:2018 certified; copies available on request. Management-system certification does not establish a particular product rating, enclosure class, efficiency level or test approval. Agree the technical requirements and supporting records in the written offer.
Related equipment and project context
Send a clearer quotation brief
Contact the Kolkata corporate office with the equipment category, duty, rating required, supply/interface voltages, quantity, site conditions and requested dispatch destination. Unknown items can be marked for technical discussion; do not assume a standard configuration.
Landline: 033 4061 3200 · ostltd@hotmail.com. The quotation checklist can help organise the brief.
Losses, winding and cooling: compare the agreed design
For a special-duty transformer, define the actual operating profile and request guaranteed losses at stated conditions. An EE Level 1/2/3 distribution schedule or a BEE star label is not automatically applicable to furnace, rectifier or solar duty. ONAN, if requested for oil-immersed equipment, means oil-natural/air-natural cooling; confirm suitability and the proposed arrangement rather than assuming it is standard.
Copper and aluminium winding options are confirmed. Material selection belongs within the complete electrical and thermal design; neither material by itself guarantees a particular loss, service life or saving. For an oil-filled enquiry, any ONAN requirement must be confirmed in the technical offer; it is not a dry-type cooling label.
Compare offered no-load losses over energised hours and load losses against the actual loading profile at agreed reference conditions. Use the buyer’s tariff and operating inputs; no customer savings or payback is invented here. The EE Level 1 versus 2 versus 3 guide explains the buying questions, and routine-testing guidance helps define acceptance documents.
Manufactured in Howrah. Enquiries through Kolkata.
OSTL’s manufacturing units are Unit 1, Howrah, West Bengal and Unit 2, Sankrail, Howrah. The corporate office is in Kolkata. Send the exact destination, specification and purchaser’s documents; no regional factory, local stock or universal buyer approval is implied.
For eastern India, use the West Bengal, Odisha, Jharkhand and Bihar pages. The Assam/North-East hub provides the enquiry route for Guwahati and wider NE destinations. Nepal, Bhutan and Bangladesh enquiries need the destination and buyer’s documentary requirements; delivery responsibilities, eligibility and commercial feasibility are agreed for that enquiry.
Contact WhatsApp +91 70035 13107, landline 033 4061 3200 or ostltd@hotmail.com. Use the RFQ checklist or discuss repair and after-sales requirements. Online forms do not create a sent enquiry; use the listed contact channels.