Best 208 to 380 Volt Transformers for Industrial and Workshop Use
The top picks here are 208V to 380V (or 400V) transformers designed for industrial, CNC, and automation setups. These units convert voltage safely between common US and international systems, helping you power equipment like CNCs, HVAC controls, and machine tooling. Best for buyers who need reliable three-phase or single-phase solutions, balanced for resistive and inductive loads, with clear safety limits. The list includes heavy-duty 3-phase step-up transformers and versatile variable frequency transformers (VFTs) for broader voltage and frequency ranges.
Summary table of chosen products:
| Product | Type | Primary–Secondary Voltages | Capacity | |
|---|---|---|---|---|
| 30 kVA 208V to 380V, 3-Phase Step Up Transformer | Autotransformer | 208V → 380V | 30 kVA | Industrial three-phase step-up power for CNCs and automation lines |
| 30 kVA 208V to 400V, 3-Phase Step Up Transformer | Autotransformer | 208V → 400V | 30 kVA | High-load three-phase applications needing 400V |
| GoHz 30 kVA 3 Phase Isolation Transformer | Dry-type isolation transformer | 380V → 208V (typical use) | 30 kVA | Isolated three-phase power for CNCs and automation |
| NZMWLNSGAW 1 Pcs VFT 380V → 220V (1P5kva) | Variable Frequency Transformer | 380V → 220V; 50/60 Hz | 5 kVA | Industrial voltage and frequency conversion for mixed loads |
| NZMWLNSGAW 1 Pcs VFT 380V → 220V (1P10kva) | Variable Frequency Transformer | 380V → 220V; 50/60 Hz | 10 kVA | Higher-capacity voltage/frequency conversion in industrial settings |
30 kVA 208V to 380V, 3-Phase Step Up Transformer
Features: Autotransformer. 3-phase to 3-phase. Maximum Resistive Load Capacity: 24 kVA. Maximum Inductive Load Capacity: 18 kVA. For safe operation, resistive load limited to 80% (×0.8) and inductive load to 60% (×0.6).
Best for: Industrial three-phase systems requiring a reliable 208V to 380V boost, such as CNC machines or automation lines. This unit is designed to handle steady resistive and inductive loads with explicit continuity limits. Caution: Do not exceed the 0.8/0.6 load factors to avoid overheating or voltage sag during peak demand.
30 kVA 208V to 400V, 3-Phase Step Up Transformer
Features: Autotransformer. 3-phase to 3-phase. Maximum Resistive Load Capacity: 24 kVA. Maximum Inductive Load Capacity: 18 kVA. Resistive load to 80% and inductive load to 60% for safe operation.
Best for: Projects needing 400V outputs from 208V sources, with similar load factor requirements as the 380V variant. Choose this if your equipment specifies 400V three-phase input at full-load conditions. Limitation: Same load factor cautions apply to avoid overheating when delivering high power.
NZMWLNSGAW 1 Pcs VFT 380V → 220V (1P5kva)
Features: Adjustable voltage and frequency regulator. Industrial automation product. Brand new with one-year warranty.
Best for: Facilities needing flexible 380V to 220V conversion with frequency adjustment, useful in plants with mixed 50/60 Hz equipment. Limitation: Warranty noted, but performance specifics (efficiency, regulation) are not detailed in the listing.
NZMWLNSGAW 1 Pcs VFT 380V → 220V (1P10kva)
Features: Adjustable voltage and frequency regulator. Industrial automation product. Brand new with one-year warranty.
Best for: Higher-capacity VFT needs up to 10 kVA, accommodating heavier loads while preserving voltage and frequency stability. Caution: The data does not specify exact regulation accuracy or transient response, so plan for some settling time under rapid load changes.
GoHz 20kVA 3 Phase Isolation Transformer
Features: Phase: 3 phase; Capacity: 20 kVA; Primary/Secondary Voltage: 120V–480V optional; Copper winding; Dry-type cooling; H-class insulation; Dyn11 wiring for stable operation.
Best for: Providing isolated, clean three-phase power for CNCs, HVAC, and automation lines. Limitation: Primary/secondary voltage range is listed as optional, which may require configuration to match your exact source and load voltages.
GoHz 30 kVA 3 Phase Isolation Transformer
Features: Phase: 3 phase; Capacity: 30 kVA; Primary/Secondary Voltage: 120V–480V optional; Dry-type cooling; Copper winding; Dyn11 wiring for stable, isolated three-phase output.
Best for: Industrial environments needing robust voltage isolation and stable three-phase power for machines like CNCs or production lines. Limitation: As a larger unit, installation space and mounting considerations are important for proper heat dissipation.
Buying Guide: How To Choose The Right 208–380V Transformer
What load type matters most?
Resistive loads (motors with near-constant current) benefit from transformers rated for higher resistive loading. Inductive loads (motors or power supplies with coils) require respecting lower inductive load limits to prevent overheating and voltage drop.
Three-phase vs. single-phase needs
Three-phase transformers are ideal for industrial equipment and CNC machines, offering smoother power delivery for heavy equipment. Single-phase units (if applicable) are typically used for smaller controls or sub-systems but are common in mixed systems when space or wiring constraints exist.
Voltage conversion direction
Determine whether you need a step-up (208V to 380V/400V) or step-down (380V/400V to 208V/220V). Some models are dual-purpose, but verify the exact primary and secondary voltages before purchase.
Isolation vs. autotransformer design
Isolation transformers provide galvanic isolation and clean power, reducing noise and grounding issues. Autotransformers are typically lighter and more economical but do not isolate the load from the source. Choose based on safety requirements and EMI considerations in your facility.
Power rating and headroom
Size the transformer to operate at or below 80% of resistive capacity and 60% for inductive loads if the manufacturer specifies these limits. This ensures reliable performance and reduces thermal stress during peak demand.
Physical installation and cooling
Dry-type transformers require adequate ventilation and ambient clearance. Consider enclosure ratings (dust, moisture) and mounting options when planning installation in factories or workshops.
Warranty and service considerations
Some units include warranties and factory support. Factor in warranty terms and the availability of service centers when planning long-term usage.
Frequently Asked Questions
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What is the difference between 208V and 380V transformers?
208V transformers are designed to convert or step up to 380V/400V in three-phase systems. They are commonly used to power equipment designed for higher voltage while balancing loads across phases.
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Do I need a transformer with isolation?
Isolation helps reduce electrical noise and protects equipment from ground loops. If EMI or sensitive electronics are involved, choose an isolation transformer.
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What does “0.8 resistive / 0.6 inductive” mean?
These are recommended maximum load factors to keep the transformer within safe thermal limits. Do not exceed these percentages to prevent overheating and efficiency loss.
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Can I use a 380V to 220V transformer for CNC machines?
Yes, if your CNC or control equipment accepts 220V on the control circuits or spindle drives. Confirm voltage tolerances and control circuitry requirements before wiring.
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How should I size a transformer for my workshop?
Estimate peak load in kVA by adding the full-load current of essential machines. Choose a transformer with at least 1.25–1.5× that peak load to ensure margin for startup surges and future expansion.
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Are VFTs reliable for frequency conversion?
Variable frequency transformers (VFTs) offer adjustable voltage and frequency, useful for mixed-frequency equipment. Ensure the frequency accuracy and regulation meet your equipment’s requirements.