Question 1

What is the difference between a distribution and a power transformer?

Accepted Answer

Distribution transformers operate at lower voltages (up to 36 kV) and capacities (50 kVA–5 MVA), stepping power down for end-user consumption. Power transformers handle higher voltages (up to 400 kV) and capacities (6–200 MVA), connecting generation to transmission networks. The design, insulation class, cooling systems, and testing requirements differ significantly between the two.

Question 2

What cooling options are available for your transformers?

Accepted Answer

We offer ONAN (Oil Natural Air Natural), ONAF (Oil Natural Air Forced), KNAN (Ester Natural Air Natural), and KNAF cooling configurations. For dry-type units, AN (Air Natural) and ANAF (Air Natural Air Forced) options are available. The optimal choice depends on ambient temperature, installation environment, and load profile.

Question 3

Do you manufacture transformers with ester (biodegradable) fluid?

Accepted Answer

Yes. We offer both natural ester and synthetic ester options across our product range. Ester-filled transformers provide a higher fire point (360°C vs 170°C for mineral oil), are fully biodegradable, and extend insulation life by actively absorbing moisture from cellulose paper. They are ideal for indoor, urban, and environmentally sensitive installations.

Question 4

What is the typical lead time for distribution transformers?

Accepted Answer

Standard distribution transformers: 12–14 weeks EXW. Pad-mounted and cast resin units: 14–16 weeks EXW. Power transformers (>10 MVA): 42–46 weeks EXW. Fast-track options are available for urgent requirements — contact our sales team for expedited schedules.

Question 5

Do you provide factory acceptance testing (FAT)?

Accepted Answer

Yes. All transformers undergo routine testing per IEC 60076 or ANSI/IEEE C57. We welcome client-witnessed FAT at our ISO/IEC 17025:2017 accredited laboratory in Dubai. Third-party witnessed testing by KEMA, CESI, or INTERTEK can also be arranged.

Question 6

What warranty do you offer?

Accepted Answer

Standard warranty is 2 years from commissioning or 30 months from delivery, whichever occurs first. Extended warranty options and Annual Maintenance Contracts (AMC) are available. Our lifecycle services team provides support throughout the transformer's operational life.

Question 7

Which international standards do your transformers comply with?

Accepted Answer

Our transformers are designed, manufactured, and tested to IEC (International), ANSI/IEEE (North American), UL (Underwriters Laboratories), CSA (Canadian), and DOE (US Department of Energy) standards. This triple-standard compliance is rare among manufacturers and enables global deployment.

Question 8

Are your transformers suitable for hazardous (ATEX) environments?

Accepted Answer

Yes. Our oil & gas range is designed for hazardous area classification (Zone 1 & Zone 2) per ATEX and IECEx standards. Features include hermetic sealing, C5-M marine-grade corrosion protection, explosion-proof accessories, and specialised cable termination boxes.

Question 9

Do you provide on-site maintenance and repair services?

Accepted Answer

Yes. Our lifecycle services division offers installation supervision, commissioning, preventive maintenance, oil analysis, repairs (on-site and factory), retrofilling (mineral oil to ester conversion), and 24/7 emergency response. We service transformers of any make or model.

Question 10

What is Vapour Phase Drying (VPD) and why does it matter?

Accepted Answer

VPD uses kerosene vapour under vacuum to extract moisture from transformer insulation to levels below 0.5% — far superior to conventional hot-air drying (which typically achieves 1–1.5%). Lower moisture content directly translates to higher dielectric strength, longer insulation life, and better impulse withstand capability. VPD is essential for power transformers rated above 33 kV.

Question 11

What is the difference between ONAN and ONAF cooling?

Accepted Answer

ONAN (Oil Natural Air Natural) relies entirely on natural convection — oil circulates by thermal buoyancy, and radiators dissipate heat to ambient air. ONAF (Oil Natural Air Forced) adds fans to the radiators, increasing cooling capacity by 25–40%. Most power transformers are dual-rated ONAN/ONAF, operating in ONAN at base load and switching to ONAF during peak demand.

Question 12

Can I retrofit my mineral oil transformer with ester fluid?

Accepted Answer

Yes, this process is called retrofilling. It involves draining the mineral oil, flushing the tank and windings, and refilling with ester fluid. The transformer's gaskets and seals must be compatible with ester (most modern materials are). Retrofilling extends insulation life, improves fire safety, and enhances environmental compliance — often more cost-effective than replacement.

Transformer FAQ — Frequently Asked Questions