Demand before nameplate totals
A 100 kVA transformer enquiry should begin with the expected operating demand, not the sum of every connected equipment nameplate. Describe which loads run together, their operating hours and the basis of any spare capacity. A project engineer should assess the duty; this page is not a sizing calculator.
Typical applications: questions, not guarantees
- A commercial-services, institutional or industrial auxiliary-load brief may raise a 100 kVA interest, but none of these applications automatically establishes the correct rating.
- For a replacement, compare actual duty with the existing nameplate and drawings, and explain why the old unit is being replaced.
- List diversity and phase-loading assumptions from the engineer, together with starting or other changing-load information where relevant.
Oil-immersed or dry-type suitability
Oil-immersed and dry-type construction have different installation, cooling and maintenance considerations. OSTL’s dry-type range is confirmed up to 3 MVA, but this does not confirm every rating/voltage/configuration. Ask the engineer and OSTL to assess the site, ventilation, fire strategy, interfaces and project specification. A dry-type label is not a blanket safety, fire-class or approval guarantee.
OSTL manufactures power and distribution transformers within an overall range of up to 10 MVA and up to 66 kV; the exact rating/voltage combination needs confirmation. Dry-type transformers are a confirmed product line up to 3 MVA. The 66 kV company-range statement must not be applied to dry-type products.
Copper or aluminium windings
OSTL confirms copper and aluminium winding options. The material should be selected within the complete electrical and performance design, not treated as a stand-alone promise of loss, efficiency or life. Ask for the product-specific selection and a clearly stated technical offer.
ONAN cooling and CRGO core requirements remain options/requirements to confirm. Neither is asserted as a guaranteed feature of this enquiry rating.
Specifications on request
No guaranteed losses, dimensions, weight, impedance, prices, stock position or default voltage is published for this rating. Request a signed technical schedule and approved drawing for the design offered.
| Topic | What to request or confirm |
|---|---|
| Electrical system | Exact offered rating, HV/LV voltage, phase, frequency, vector group and tapping arrangement. |
| Construction | Oil-immersed or dry-type design, insulation system, cooling, winding material, core and enclosure requirements. |
| Guaranteed performance | Losses and reference conditions, impedance, temperature limits and other agreed duty requirements. |
| Physical and interfaces | Approved dimensions, weight, fluid quantity where relevant, terminal arrangement, drawings and accessories. |
| Standards and acceptance | Applicable standards/editions, current BIS category/rating scope, agreed test/inspection documents. |
| Commercial scope | Quantity, availability/build-to-order terms, price/scope if quoted, delivery destination and confirmed dispatch timeline. |
Clarify the demand assumption
Ask how current operating demand, future allowances and any seasonal duty have been represented. If the brief is incomplete, request a list of missing inputs rather than accepting a standard-voltage or standard-loss assumption.
BIS scope and acceptance documents
OSTL acquired BIS licences in all five major transformer categories in 2020. Request the current licence documents and the applicable product/rating scope; this is not evidence of registration or approval by a utility or procurement platform. Routine tests per IS 1180 / IS 2026 are confirmed; the applicable standard and agreed test/document schedule must be checked for the offered design.
Send a clearer quotation request
- Required kVA/MVA, HV/LV voltage, phase, frequency and transformer construction.
- Application, load schedule/duty, site conditions, interfaces and relevant single-line diagram.
- Specified losses, impedance, temperature requirements and reference conditions, if defined by the project engineer.
- Quantity, delivery state/country, requested dispatch timeline and boundaries for freight, unloading and installation.
Online enquiry submission is not enabled. Contact the Kolkata office by WhatsApp +91 93310 15264, landline 033 4061 3200 or ostltd@hotmail.com.
Related project guidance
Choose your buyer context
See the site and operating questions for six customer segments.
↗TENDER BUYERSReview documents and eligibility
Separate BIS licence scope, technical compliance and buyer-specific vendor status.
↗ALL RATING INTERESTSReturn to the ratings guide
Compare the requested rating interests without assuming approved or stocked models.
↗Questions before you enquire
Is this a confirmed 100 kVA stocked model?
No. This page is a rating-specific enquiry guide. OSTL must confirm technical suitability, the actual product design, availability and licence applicability.
Are guaranteed specifications and prices published here?
No. Ask for the offered design’s signed technical schedule, approved drawing and quotation. Performance values, dimensions, weight, price and dispatch terms are not inferred from the rating.