500kva transformer
The parameters, cost, and model selection of a 500 kVA transformer need to be determined according to factors such as the **number
of phases, voltage level, and type**. The following is a detailed analysis:
I. Core Parameters: Current Calculation
1. Three-phase Transformer (Most Common)
**Formula**:
| Voltage Level (V) | Calculation Formula | Rated Current (A) | Application Scenarios |
| 480V | 500,000 ÷ (1.732×480) | 601.4 A | Industrial power distribution (Mainstream in the United States) |
| 600V | 500,000 ÷ (1.732×600) | 481.1 A | High-voltage industrial systems |
| 10kV | 500,000 ÷ (1.732×10,000) | 28.87 A | High-voltage power transmission to distribution |
| 208V | 500,000 ÷ (1.732×208) | 1,389 A | Low-voltage dense loads (such as data centers) |
2. Single-phase Transformer (Rare, with Extremely Large Current)
**Formula**:
| Voltage Level (V) | Current (A) | Explanation |
| 240V | 2,083 A | 500 kVA is rarely used for single-phase loads |
| 480V | 1,042 A | Special industrial equipment (such as large welding machines) |
II. Cost Range (Market Reference in 2025)
| Type | Domestic/Joint Venture Brands | Imported Brands (such as Eaton, Siemens) |
| Dry-type Transformer | ￥50,000~￥150,000 | $10,000~$25,000 (such as Eaton $18,500) |
| Oil-cooled Transformer | ￥40,000~￥120,000 | $8,000~$20,000 (such as Siemens $15,000) |
2. Second-hand/Refurbished Transformers
- **eBay/UsedEquip in the United States**:
- Three-phase dry type (480V→208Y/120V): **$5,000~$10,000** (such as the refurbished Square D for $7,500)
- Oil-cooled type (with NEMA 3R casing): **$6,000~$12,000**
3. Additional Costs for Special Configurations
- **Protection Level**: IP54 is **15%~20%** more expensive than IP20.
- **Winding Material**: All-copper windings are **30%~50%** more expensive than aluminum windings.
- **Intelligent Monitoring**: Integrating the Internet of Things module increases **$2,000~$5,000**.
III. Type Selection and Application Scenarios
1. Dry-type Transformer (Recommended for Indoor Use)
- **Advantages**: No risk of oil flammability, maintenance-free, and low noise (< 65 dB).
- **Scenarios**: Commercial buildings, data centers, hospitals (such as a 500 kVA dry-type transformer used for 480V to 208V
power distribution).
2. Oil-cooled Transformer (Recommended for Outdoor/Industrial Use)
- **Advantages**: Good heat dissipation, large capacity, and 10%~20% lower cost.
- **Scenarios**: Factories, substations, remote areas (requiring an oil storage tank and fire protection measures).
3. Isolation Transformer
- **Function**: Electrical isolation and suppression of harmonics.
- **Price**: **20%~30%** more expensive than ordinary power distribution transformers, commonly used for power supply to
precision equipment.
IV. Local Selection Suggestions in the United States
1. **Parameter Confirmation**:
- Input voltage (such as 480V, 13.8kV), output voltage (such as 208Y/120V, 480V)
- Number of phases (default three phases), NEC certification (such as UL 1561)
2. **High-cost-effective Models**:
- **Square D 500T3H** (Three-phase dry type, 480V→208Y/120V): **$12,500** (Brand-new)
- **Eaton Cutler-Hammer 500 kVA** (Oil-cooled type, NEMA 3R): **$9,800** (Second-hand and refurbished)
3. **Installation Precautions**:
- Dry-type transformers need to reserve a heat dissipation space of **≥1 meter**, and oil-cooled transformers need to comply
with Article 450 of NFPA 70 (NEC).
- Conductor specification: For a 480V three-phase current of 601A, a **350 kcmil copper cable** (current-carrying capacity 650A)
is required.
V. Summary and Comparison
| Demand Scenarios | Recommended Type | Current Range | Budget Range |
| Indoor commercial power distribution | Three-phase dry type | 208V→1,389 A | $10,000~$15,000 |
| Outdoor industrial power supply | Oil-cooled type + NEMA 3R | 480V→601 A | $8,000~$12,000 |
| Single-phase equipment with extremely large current | Special customized single-phase | 240V→2,083 A | Separate quotation required |
**Note**: The actual price should be subject to the quotation from the supplier. It is recommended to provide complete parameters
(such as voltage, cooling method, and protection level) to obtain an accurate solution.
