Comprehensive technical data for 45 kVA dry transformers including dimensions, weight, full load amps, installation tips, and sizing guidance
Quick Specifications
| Rated Power: | 45 kVA | Phase: | Three-Phase |
| Primary Voltage: | 480V | Secondary Voltage: | 208Y/120V |
| Weight: | 360 lbs (163 kg) | Efficiency: | 98.5% |
| Dimensions (H×W×D): | 38″ × 22″ × 17″ (965 × 559 × 432 mm) | ||
A 45 kVA transformer is commonly used in Medium commercial facilities. This guide provides complete specifications to help engineers and purchasers select and install 45 kVA transformers correctly.
45 kVA Transformer Dimensions
| Dimension | Metric (mm) | Imperial (inches) |
|---|---|---|
| Height (H) | 965 mm | 38″ |
| Width (W) | 559 mm | 22″ |
| Depth (D) | 432 mm | 17″ |
45 kVA Transformer Weight
| Weight Type | Pounds (lbs) | Kilograms (kg) |
|---|---|---|
| Dry-Type Transformer | 360 lbs | 163 kg |
| Oil-Filled Equivalent* | ~540 lbs | ~244 kg |
| Shipping Weight (Approx.) | ~396 lbs | ~179 kg |
*Oil-filled transformer weight is estimated at approximately 1.5× dry-type weight.
Full Load Amps at Various Voltages
The following table shows calculated full load amperage for a 45 kVA three-phase transformer:
| Voltage | Full Load Amps | Suggested Wire Size |
|---|---|---|
| 120V | 216.5 A | 250 MCM |
| 208V | 124.9 A | 1/0 AWG |
| 240V | 108.3 A | #1 AWG |
| 277V | 93.8 A | #2 AWG |
| 480V | 54.1 A | #6 AWG |
| 600V | 43.3 A | #6 AWG |
Three-Phase:
Amps = (kVA × 1000) ÷ (Voltage × 1.732)Example at 480V:
54.1 A = (45 × 1000) ÷ (480 × 1.732)Electrical Specifications
| Parameter | Value | Notes |
|---|---|---|
| Rated kVA | 45 kVA | At rated voltage and frequency |
| Frequency | 60 Hz | 50 Hz available on request |
| No-Load Loss | 130 W | Core/iron losses (typical) |
| Load Loss | 480 W | Copper losses at 100% load |
| Total Losses | 610 W | At 100% load |
| Impedance | 4.0% | ±7.5% tolerance per IEEE |
| Efficiency | 98.5% | At 100% load |
| Sound Level | ~40 dB | Per NEMA ST-20 (estimated) |
⚠️ Important Considerations for 45 kVA Transformers:
- At 45 kVA, ensure adequate ventilation clearance (minimum 3″ sides, 6″ top) for proper cooling.
When is a 45 kVA Three-Phase Transformer the Right Choice?
A 45 kVA three-phase transformer is ideal for:
- Small manufacturing facilities with 3-phase equipment
- Commercial kitchens with three-phase ovens
- HVAC systems with 3-phase compressors up to 22 HP
- Elevator and escalator power supply
- Multi-tenant building common areas
Three-Phase Advantage: Compared to single-phase, this transformer delivers 39.0 kW at unity power factor with balanced loading across all phases.
Typical Load Examples for 45 kVA
Example load distribution for a 45 kVA installation:
| Load Type | Estimated Demand |
|---|---|
| Three-phase HVAC compressor | 18 kVA |
| 3-phase motors (combined) | 13 kVA |
| Lighting transformer | 6 kVA |
| Receptacle loads | 6 kVA |
Note: Actual loads vary. Always perform a detailed load calculation for your specific application.
Related Transformer Sizes
Compare with adjacent kVA ratings:
| kVA Rating | Link |
|---|---|
| 30 kVA Three-Phase | 30 kVA Specifications → |
| 45 kVA Three-Phase | Current Page |
| 75 kVA Three-Phase | 75 kVA Specifications → |
Frequently Asked Questions
What are the dimensions of a 45 kVA transformer?
A typical 45 kVA dry three-phase transformer measures approximately 38″ H × 22″ W × 17″ D (965 × 559 × 432 mm). Dimensions vary by manufacturer.
How much does a 45 kVA transformer weigh?
A 45 kVA dry transformer typically weighs around 360 lbs (163 kg). Oil-filled transformers of the same rating weigh approximately 540 lbs.
What is the full load amperage of a 45 kVA transformer at 480V?
At 480V, a 45 kVA three-phase transformer has a full load current of 54.1 amps.
What loads can a 45 kVA transformer handle?
A 45 kVA transformer can supply up to 45 kVA of apparent power. For typical loads with 0.85 power factor, this equals approximately 38.2 kW of real power.
Related Resources
📊 Complete Reference Charts:
- Transformer Sizing Chart – Compare all kVA ratings with dimensions & weights
- Transformer Full Load Amps Chart – FLA reference for all voltages
Related Articles
- Three Phase Transformer: Complete Guide
- Transformer Testing: Complete Guide
- Transformer Protection: Complete Guide
Standards & References
- IEEE C57.12.01 – General Requirements for Dry-Type Transformers
- IEEE C57.12.91 – Test Code for Dry-Type Transformers
- NEMA TP-1 – Guide for Determining Energy Efficiency
- DOE 10 CFR 431 – Energy Conservation Standards
Disclaimer: Specifications shown are typical reference values compiled from multiple industry sources. Actual specifications vary significantly by manufacturer, model, enclosure type, and configuration. Always consult manufacturer datasheets for exact specifications before ordering or installation. Data accuracy verified using standard electrical engineering formulas. Last updated: January 2026