Comprehensive specifications for 225 kVA ONAN oil-filled transformer including dimensions, weight, oil volume, and electrical data
Quick Specifications
| Rated Power: | 225 kVA | Phase: | Three-Phase |
| Primary Voltage: | 12470Y/7200V | Secondary Voltage: | 208Y/120V |
| Cooling Class: | ONAN | BIL Rating: | 125 kV |
| Weight: | 2400 lbs (1090 kg) | Oil Volume: | 100 gallons (379 L) |
| Dimensions (H×W×D): | 60″ × 46″ × 35″ (1530 × 1160 × 900 mm) | ||
A 225 kVA oil-filled transformer is commonly used for Large industrial plants. This guide provides complete specifications for utility engineers, electrical contractors, and procurement professionals.
225 kVA Oil-Filled Transformer Dimensions
| Dimension | Metric (mm) | Imperial (inches) |
|---|---|---|
| Height (H) | 1530 mm | 60″ |
| Width (W) | 1160 mm | 46″ |
| Depth (D) | 900 mm | 35″ |
🔧 Installation Note: This major 225 kVA oil-filled transformer requires careful planning:
- Weight: 2400 lbs – crane installation required
- Oil Volume: 100 gallons – EPA SPCC containment required (110% = 110 gallons)
- Foundation: Engineered concrete pad with 1200 lb/sq.ft minimum capacity
- Fire Code: Verify setback distances per NFPA 70 and local fire code
- Commissioning: Oil sample testing, turns ratio test, and insulation resistance test recommended before energizing
Weight and Oil Specifications
| Specification | Value | Notes |
|---|---|---|
| Total Weight (with oil) | 2400 lbs (1090 kg) | Includes all oil and accessories |
| Oil Volume | 100 gallons (379 L) | Mineral Oil |
| Oil Type | Mineral Oil | IEEE C57.106 compliant |
| Containment Required | 110 gallons | 110% per EPA SPCC |
Electrical Specifications
| Parameter | Value | Notes |
|---|---|---|
| Rated kVA | 225 kVA | At rated voltage and ONAN cooling |
| Primary Voltage | 12470Y/7200V | Standard utility distribution voltage |
| Secondary Voltage | 208Y/120V | Service voltage |
| Cooling Class | ONAN | Oil Natural, Air Natural |
| BIL Rating | 125 kV | Standard for 23kV-35kV primary |
| No-Load Loss | 480 W | Core losses |
| Load Loss | 1900 W | At rated load |
| Total Losses | 2380 W | At 100% load |
| Impedance | 5.0% | Per IEEE C57.12.00 |
| Efficiency | 99.0% | At rated load |
| Sound Level | ~50 dB | Per NEMA TR-1 |
Secondary Full Load Amps
Full load amperage at secondary voltage for 225 kVA three-phase transformer:
| Secondary Voltage | Full Load Amps | Conductor Size |
|---|---|---|
| 120V | 1082.6 A | 750 MCM+ |
| 208V | 624.6 A | 750 MCM+ |
| 240V | 541.3 A | 750 MCM+ |
| 277V | 469.0 A | 750 MCM+ |
| 480V | 270.6 A | 350 MCM |
Three-Phase:
Amps = (kVA × 1000) ÷ (Voltage × 1.732)Example at 480V:
270.6 A = (225 × 1000) ÷ (480 × 1.732)Oil Maintenance Guidelines for 225 kVA Transformer
Proper maintenance of the 100 gallons of Mineral Oil in this transformer is critical for long-term reliability:
| Maintenance Task | Frequency | Purpose |
|---|---|---|
| Visual Oil Level Check | Monthly | Detect leaks, ensure adequate level |
| Oil Sample Analysis | Annually | Dielectric strength, dissolved gas analysis (DGA) |
| Oil Filtration/Reconditioning | Every 3-5 years | Remove moisture and contaminants |
| Silica Gel Breather Check | Quarterly | Ensure moisture protection |
| Bushing Inspection | Annually | Check for cracks, contamination, oil leaks |
⚠️ Oil Handling Safety:
- Always use proper PPE when handling transformer oil
- Dispose of contaminated oil according to EPA regulations
- Never mix different oil types without compatibility testing
- Maintain SPCC containment at all times
When to Choose a 225 kVA Three-Phase Oil-Filled Transformer
A 225 kVA three-phase oil-filled transformer with ONAN cooling represents major infrastructure:
- Primary utility substations
- Large industrial complexes
- Data center outdoor power distribution
- Mining and heavy industrial operations
- Utility grid tie-in points
Engineering Considerations:
- Coordinate with utility for primary metering requirements
- Arc flash analysis and protective relaying required
- Consider redundant transformer configuration
- Plan for oil containment per EPA SPCC regulations
- Fire suppression systems may be required by code
Typical Load Distribution for 225 kVA Oil-Filled Transformer
Example utility distribution loads for a 225 kVA oil-filled transformer:
| Load Type | Estimated Demand |
|---|---|
| Three-phase motor loads | 90 kVA |
| HVAC systems | 56 kVA |
| Lighting transformers | 33 kVA |
| Receptacle/misc loads | 45 kVA |
Note: Utility distribution varies by application. Consult with utility engineer for specific load allocations.
Related Oil-Filled Transformer Sizes
Compare with adjacent kVA ratings:
| kVA Rating | Link |
|---|---|
| 150 kVA Three-Phase | 150 kVA Oil-Filled Specs → |
| 225 kVA Three-Phase | Current Page |
| 300 kVA Three-Phase | 300 kVA Oil-Filled Specs → |
Frequently Asked Questions
How much oil does a 225 kVA oil-filled transformer contain?
A 225 kVA three-phase oil-filled transformer typically contains 100 gallons (379 liters) of Mineral Oil insulating oil.
What are the dimensions of a 225 kVA oil-filled transformer?
Typical dimensions are 60″ H × 46″ W × 35″ D (1530 × 1160 × 900 mm).
How much does a 225 kVA oil-filled transformer weigh?
A 225 kVA oil-filled transformer weighs approximately 2400 lbs (1090 kg) including oil.
What is the BIL rating for a 225 kVA transformer?
The standard BIL (Basic Insulation Level) rating is 125 kV, which is standard for 23kv-35kv primary.
Related Resources
📊 Complete Reference Charts:
- Transformer Sizing Chart – Compare all kVA ratings
- Transformer Full Load Amps Chart – FLA reference for all voltages
Related Articles
- Transformer Oil: Complete Guide to Types, Testing & Maintenance
- Three Phase Transformer: Complete Guide
- Transformer Protection: Complete Guide
Standards & References
- IEEE C57.12.00 – General Requirements for Liquid-Immersed Distribution Transformers
- IEEE C57.12.90 – Test Code for Liquid-Immersed Distribution Transformers
- IEEE C57.106 – Guide for Acceptance and Maintenance of Insulating Oil
- NEMA TR-1 – Transformers, Regulators and Reactors
- EPA 40 CFR 112 – SPCC Requirements
Disclaimer: Specifications shown are typical reference values. Actual specifications vary by manufacturer, voltage class, and application. Oil-filled transformers require proper containment, maintenance, and environmental compliance. Always consult manufacturer datasheets and local codes. Last updated: January 2026