ANSI/IEEE StandardUL/CSA Listed
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Three Phase
Pad Mounted Transformer
ANSI/IEEE Standard • Loop Feed / Radial Feed
Pad-mount transformers are oil-filled units designed for outdoor mounting. The core and coils are enclosed in a steel oil-filled tank, with terminals accessible in an adjacent lockable wiring cabinet featuring separate high and low-voltage compartments.
Power ratings range from 45 to 5000 kVA and often include built-in fuses and switches. Primary power cables can be connected with elbow connectors, operable when energized using a hot stick for flexible repair and maintenance.
Capacity
45 - 5000 kVA
High Voltage
Up to 35 kV
Frequency
50 / 60 Hz
Standard
ANSI/IEEE
Ideal Applications
Commercial & Industrial
Reliable power for shopping malls, factories, and office complexes.
Renewable Energy
Solar and wind farm step-up applications with special duty cycles.
Data Centers
High-reliability power distribution for critical infrastructure.
Frequently Asked Questions
What is a pad-mounted transformer?
A pad-mounted transformer is a ground-mounted electric power distribution transformer housed in a locked steel cabinet mounted on a concrete pad. It's designed for underground power distribution systems and is commonly used in commercial, industrial, and residential applications.
What are the main advantages of pad-mounted transformers?
Pad-mounted transformers offer several advantages: enhanced safety with tamper-resistant enclosures, aesthetic appeal as they're less visible than pole-mounted units, protection from weather and vandalism, easier maintenance access, and suitability for underground cable systems.
What voltage ratings are available?
Our three-phase pad-mounted transformers are available in a wide range of voltages: High voltage up to 35kV (including 12kV, 15kV, 25kV, 35kV classes), and low voltage options including 208V, 240V, 416V, 480V, and 600V in various configurations (Delta or Wye).
What capacity (kVA) options do you offer?
We manufacture three-phase pad-mounted transformers from 45 kVA up to 5000 kVA. Standard sizes include: 45, 75, 112.5, 150, 225, 300, 500, 750, 1000, 1250, 1500, 1750, 2000, 2250, 2500, 2750, 3000, 3750, and 5000 kVA.
What standards do your transformers comply with?
Our pad-mounted transformers comply with ANSI/IEEE standards including C57.12.00 (General Requirements), C57.12.22 (Pad-Mounted Transformers), C57.12.26 (Separable Connectors), and C57.12.28 (Enclosure Integrity). We also hold UL and CSA certifications.
What is the typical lead time for delivery?
Standard configurations typically have a lead time of 8-12 weeks. Custom specifications may require 12-16 weeks. Rush orders can be accommodated depending on current production schedule. Contact our sales team for specific delivery timelines.
Do you offer installation services?
While we don't directly provide installation services, we offer comprehensive installation manuals, technical support, and can recommend qualified installation partners in your region. Our engineering team is available to answer any installation-related questions.
What testing is performed before shipment?
Every transformer undergoes rigorous testing per ANSI C57.12.90 including: Heat Run Test, ANSI Impulse Test, Audible Sound-Level Test, 8 or 24-Hour Leak Test, Temperature Test, Turn Ratio Test, Windings Resistance Test, Polarity Test, and Induced Voltage Test.
What insulation materials are used in pad-mounted transformers?
Our pad-mounted transformers use high-quality mineral oil or FR3 bio-based dielectric fluid as the primary insulation medium. The windings are insulated with Nomex paper or Kraft paper, and bushings use porcelain or polymer materials. All insulation materials meet or exceed ANSI/IEEE standards for dielectric strength and thermal performance.
Can the transformer be used in harsh weather conditions?
Yes, our pad-mounted transformers are specifically designed for outdoor installation in various climates. The sealed steel enclosure provides IP54 protection against dust and water ingress. The cabinet is powder-coated with corrosion-resistant paint suitable for coastal, industrial, and extreme temperature environments (-40°C to +50°C ambient temperature).
What maintenance is required for pad-mounted transformers?
Pad-mounted transformers require minimal maintenance. We recommend annual visual inspections to check for oil leaks, corrosion, and physical damage. Oil sampling and testing should be performed every 3-5 years to monitor dielectric strength and moisture content. The cabinet locks and hinges should be lubricated annually. Detailed maintenance procedures are provided in the operation manual.
How is the transformer protected from overload and short circuits?
Our transformers incorporate multiple protection features: primary side fuses or circuit breakers rated for the transformer capacity, secondary side circuit breakers or fuses, pressure relief valves to prevent tank rupture, and optional temperature monitoring devices. The design includes impedance values that limit short-circuit currents and withstand mechanical stresses during fault conditions.
What is the expected lifespan of a pad-mounted transformer?
With proper maintenance, our pad-mounted transformers have an expected service life of 25-30 years or more. The actual lifespan depends on operating conditions, load profile, ambient temperature, and maintenance practices. We use high-grade electrical steel, copper windings, and premium insulation materials to ensure long-term reliability and performance.
Can the transformer be relocated after installation?
Yes, pad-mounted transformers can be relocated if necessary. The process involves de-energizing the unit, disconnecting cables, draining the oil (if required for weight reduction), lifting with appropriate equipment (crane or forklift), and transporting to the new location. The concrete pad at the new site must meet dimensional and load-bearing requirements. Professional installation services are recommended for relocation.
What documentation is provided with the transformer?
Each transformer ships with comprehensive documentation including: Factory test reports (heat run, impulse, sound level, leak test), Nameplate data and wiring diagrams, Operation and maintenance manual, Installation guidelines and safety instructions, Warranty certificate, and Certification documents (UL, CSA, IEEE compliance). All documentation is provided in English, with other languages available upon request.
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Certified & Tested By
Designed & Manufactured in Compliance With
IEEE C57.12
IEC 60076
CEI EN 50588
ANSI
GB/T
All products undergo rigorous testing and quality control to ensure compliance with international standards
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