Every compute operation runs on the same critical piece of infrastructure: the transformer. Whether you're deploying a single MW container or building a few hundred MW industrial site, the transformer is what converts medium-voltage grid power into low-voltage to supply your ASIC and GPU fleets. Get it right, rigs stay online. Get it wrong, and you face outages, tripped breakers, overheating, and hardware damages.

Yet for a component this critical, transformers remain one of the least-discussed topics in compute infrastructure. Nearly every build involves custom engineering: available grid voltage, site location, total load, and cooling configuration all drive the spec. Lead times for custom builds typically run 12–18 weeks when working with suppliers that have strong manufacturing connections but can stretch significantly longer without the right sourcing network. Spec mismatches are common and costly. As operators push toward higher power densities with the latest-gen ASICs like the Antminer S21 series and Whatsminer M70 series, or GPU-dense AI inference racks, the demand on electrical infrastructure has never been greater.

This guide covers the top transformer suppliers serving Bitcoin mining and data center operators.

TLDR

• Transformers are the most critical and most underspecified piece of compute infrastructure — spec mismatches and lead time surprises are the two biggest pain points operators face, whether building a Bitcoin mining site or an AI/HPC data center.
• Size transformers to no more than 80% of rated kVA capacity. Mining runs at full load 24/7 — unlike utility transformers that see daily peaks and valleys — and sustained operation near 100% shortens transformer life.
• The standard winding configuration for Bitcoin mining is Delta-Wye (Dyn11). It cancels triplen harmonics from switching power supplies before they reach the grid. Always confirm with your supplier.
• Specify K-13 or higher for harmonic tolerance on all compute loads. ASIC miners and GPU clusters both generate non-sinusoidal current that standard transformers are not rated to handle continuously.
• Default output voltage for most Bitcoin mining sites: 415Y/240V. Use 480Y/277V only if your miners are rated for 277V input and your transformer is wired correctly for all connected loads. Most miners still ship with 240V PSUs.
• Typical lead time through Luxor’s partner network: ~12–18 weeks (~15 weeks a safe planning estimate). Have your specs — grid voltage, total load, output voltage, cooling config — ready before reaching out. Contact [email protected].

Transformer Types Used in Bitcoin Mining & Data Centers

Before diving into suppliers, here are the transformer types most commonly deployed in compute:

• Padmount Transformers: The workhorse of container-based mining. Three-phase, oil-filled, ground-level units that step down medium voltage (12.47 kV–34.5 kV) to low voltage for ASIC power supplies. Output voltage selection matters: 415Y/240V is the traditional standard and is compatible with virtually all miner models from the S9 through virtually all current models. 240V is the standard and is supported on approximately 99% of ASIC miners; the rare exceptions include three-phase units like the T21 and certain 380–415V hydro-cooled variants. 480Y/277V is only appropriate for miners equipped with PSUs rated for 277V input, such as the APW171215 (shipping on S19J XP and most current S21 models); running 240V-rated miners at 277V can cause hardware issues and may void manufacturer warranties. Note that transformer configuration must also account for your cooling system: in a 415Y/240V deployment, miners connect phase-to-neutral (240V) while fans and other three-phase loads connect phase-to-phase (415V) — both from the same transformer. Most mining containers are sized to pair with 1,000–2,500 kVA padmount units.
• Substation / Skid-Mounted Transformers: Purpose-built for large-scale operations (5MW+). These units handle higher kVA ratings and can be integrated with switchgear in a prefabricated skid package. Recommended for: industrial-scale sites where power delivery infrastructure is being built from scratch.
• Dry-Type Transformers: Air-cooled, no oil. Lower maintenance requirements and better suited for indoor or enclosed installations. Less efficient than oil-filled units at high loads, but used in smaller deployments and jurisdictions with restrictions on oil-filled equipment. Dry-type cooling configurations: AN (natural air convection) and AF (forced air via fans). Oil-filled transformers also have multiple cooling configurations worth knowing: ONAN (oil natural, air natural — self-cooled), ONAF (oil natural, air forced — fans added), OFAF (oil forced, air forced), and OFWF (oil forced, water forced — used in high-capacity or space-constrained installations). Most padmount units deployed in Bitcoin mining are ONAN or ONAF.
• Power Transformers (High Voltage): For operations connecting directly to transmission-level grids (66 kV–230 kV). Required for very large sites with dedicated utility interconnects. Long lead times and high cost (plan 12–18 months ahead).
• Winding Configurations: The winding configuration determines how voltage is introduced and extracted from the transformer. The standard for Bitcoin mining is Delta-Wye (Delta primary, Wye secondary, written as Dyn11 or similar). This configuration traps and circulates triplen harmonics generated by switching power supplies within the delta primary before they can travel back into the grid, improving power quality and reducing stress on both the transformer and upstream equipment. When sourcing transformers for mining or compute, confirm Delta-Wye winding and request the vector group designation from your supplier.

Key sizing note: applying the 80% rule, a 20MW site needs approximately 25 MVA of transformer capacity — typically 10 units of 2,500 kVA padmount transformers. Multiple smaller units reduce fault exposure and simplify breaker sizing versus a single large transformer.

Top 10 Transformer Suppliers for Bitcoin Mining & Data Centers

The following list is based on mining-specific experience, product range, lead times, geographic coverage, and certifications. 

1. EAC Global

📍 United States

EAC Global is a US-based transformer specialist with experience supplying power equipment across industrial, Bitcoin mining, and data center applications. Their catalog spans padmount and substation transformers suited for mid-to-large compute deployments, with an emphasis on custom specification and responsive quoting. For operators building sites with specific grid interconnect requirements or non-standard voltage configurations, EAC's engineering-forward approach is a meaningful advantage.

• Key Products/Specialties: Power transformers, padmount transformers, substation transformers, custom builds
• Website: https://www.eacglobalinc.com/transformers/

2. Maddox Transformer

📍 United States (multiple locations)

Maddox is one of the most active transformer suppliers in the North American Bitcoin mining and data center market, with documented deployments across mining operations and a well-known presence in the community. Their product range covers everything from low-voltage dry-type units to three-phase padmount and substation transformers, the full spectrum of what a compute site needs at any scale. Notably, Maddox has published specific guidance on sizing and derating for bitcoin mining loads. They also offer rental and repair services, which matters for operators who need temporary power or fast swap-outs during equipment failures.

• Key Products/Specialties: Padmount (single and three-phase), substation transformers, dry-type, switchgear, rentals, repair
• Website: https://www.maddox.com/

3. Journey Advisors

📍 United States

Journey Advisors is an active Luxor infrastructure partner specializing in transformer, substation and switchgear sourcing and procurement advisory for Bitcoin mining and data center operators. Rather than manufacturing transformers directly, Journey Advisors works through a close network of vetted manufacturing partners primarily based in Asia, enabling competitive pricing, shorter lead times, and spec-matched sourcing for a wide range of project types. For operators who need a knowledgeable intermediary to navigate custom transformer procurement, Journey Advisors provides hands-on support from spec development through delivery.

• Key Products/Specialties: Transformer sourcing advisory, Asian supply chain procurement, custom spec development, project logistics
• Website: Contact [email protected] for a warm introduction.

4. D-Volt

📍 North America

D-Volt offers a focused product line of distribution transformers well-suited to Bitcoin mining container deployments and modular data center buildouts. Their three-phase padmount offering covers the standard configurations used in container-based operations, and their catalog includes single-phase and polemount variants for distributed or off-grid setups. D-Volt is a strong option for operators sourcing padmount units for modular compute deployments.

• Key Products/Specialties: Three-phase padmount, single-phase padmount, single-phase polemount, power transformers, panel boards, auto reclosers
• Website: https://www.d-volt.co/products

5. JS Yawei Transformer

📍 China (global supply)

JS Yawei is a Chinese transformer manufacturer with global export capabilities and strong manufacturing connections that support competitive lead times. For operators building at scale who need cost-competitive transformer infrastructure such as padmount and oil-immersed units for large container mining sites or data center campuses, Yawei offers competitive pricing and manufacturing capacity. 

• Key Products/Specialties: Oil-immersed transformers, padmount transformers, substation transformers, custom builds
• Website: https://shxyw-transformer.com/

6. Kerun Power (Kerun Intelligent Control Co., Ltd.)

📍 China (Shenzhen-based, North American coverage)

Kerun is a publicly listed Chinese transformer manufacturer (stock code: 920062) with a dedicated data center and energy infrastructure solutions practice. Their product range covers oil-immersed units from 10 kV up to 220 kV, dry-type transformers from 10–35 kV, and complete skid-mounted substation solutions, well-suited for Bitcoin mining sites and high-density data centers that need integrated power delivery packages. Kerun has a U.S. contact presence, which reduces friction for North American procurement, and their data center solutions practice gives them relevant experience across both compute segments.

• Key Products/Specialties: Oil-immersed power transformers (10 kV–220 kV), dry-type transformers, box-type substations, switchgear, data center and energy storage solutions
• Website: https://kerunpower.com/

7. Daelim Transformer

📍 China (manufacturing), US stock in Houston, CA & Florida

Daelim is one of the most prolific transformer suppliers serving both the Bitcoin mining market and large-scale data centers in North America. Deployments include 20 units to a Texas mining site, 90 units to a Calgary data center, four substation transformers to a 20MW mine in Venezuela, and a separate 250MW project requiring 100 padmount units. All units are UL-listed, compliant with IEEE C57.12.34, and stocked in the US for shorter lead times. Their expertise covers the common grid voltages used in North American deployments and output configurations standard for both ASIC mining equipment and modern data center power supplies.

• Key Products/Specialties: Padmount transformers (three-phase and single-phase), substation transformers, power transformers (up to 230 kV / 300 MVA), pole-mounted, distribution transformers, rental transformers
• Website: https://www.daelimtransformer.com/all-products.html

8. JSHP Transformer (JiangSu HuaPeng Transformer Co., Ltd.)

📍 China (manufacturing), US office in San Jose, CA

JSHP is a 50+ year-old Chinese transformer manufacturer (founded 1967) with a proven track record across high-stakes power infrastructure globally. Their production line reaches up to 750 kV / 1,000 MVA, and they have shipped 11,000+ units of 110 kV–525 kV transformers and shunt reactors worldwide. Their portfolio includes dry-type units up to 110 kV, with documented data center deployments including a record-breaking 110kV/35kV 40MVA dry-type unit placed in service at a Shanghai data center in 2020. For North American compute infrastructure, JSHP is actively supplying 250+ UL-listed 2,500 kVA padmount transformers to US Bitcoin mining clients, and has delivered 138kV substation transformers to US mining operators. Their manufacturing speed is notable: they delivered a 318MVA GSU in 82 days and shipped 57 transformers to Japan in 6 weeks following the 2011 Tohoku earthquake. JSHP’s US entity (San Jose, CA) supports North American procurement and on-site service.

• Key Products/Specialties: High-voltage power transformers (up to 750 kV / 1,000 MVA), dry-type transformers (up to 110 kV), padmount distribution transformers (UL-listed, 2,500 kVA), generator step-up (GSU) transformers, solar/wind step-up transformers, skid/container solutions
• Website: https://www.jshp.com/

9. JCL Energy

📍 United States

JCL Energy has built a strong reputation in the Bitcoin mining market specifically around solving the lead time problem. They claim the largest in-stock inventory of new three-phase padmount transformers in the US, a meaningful differentiator for operators who can't wait on custom builds. Their mining-focused sales team and commitment to fast delivery make them a practical option for anyone running up against a site-ready deadline.

• Key Products/Specialties: Three-phase padmount transformers (in-stock inventory), substation transformers, custom builds, rentals
• Website: https://jcl.energy/markets-we-serve/bitcoin-mining-transformers/

10. Meta Power Solutions (MPS)

📍 United Kingdom / International

MPS has developed a compute-specific transformer product that addresses one of the common capital cost issues in high-density buildouts: expensive switchgear. By integrating switchgear directly into their padmount units, MPS reduces both cost and installation complexity. Their documentation on optimal kVA sizing reflects their deployment experience across both mining and data center applications. Output voltage options include 415Y/240V, suitable for ASIC and GPU power supply inputs.

• Key Products/Specialties: Three-phase padmount distribution transformers with integrated switchgear, custom mining and data center configurations (1,000–5,000 kVA), aluminum and copper winding options
• Website: https://metapowersolutions.com/applications/bitcoin-mining/

How to Choose a Transformer for Your Compute Site

The right transformer for your operation depends on four primary factors, and because nearly every build is custom, it pays to have these answers ready before you reach out to a supplier:

1. Total site load (kW/MW): Calculate total load across all ASIC miners, cooling systems, and auxiliary equipment. A critical rule of thumb is to never size a transformer to 100% of load. Size it to operate at no more than 80% of its rated kVA capacity. The 20% headroom exists to account for the continuous heat and harmonic stress generated by mining loads. Utility transformers see peaks and valleys throughout the day; mining transformers run near full capacity 24/7, and sustained operation at or near 100% shortens transformer life significantly. For container-based sites, your container spec (e.g., a 1.2MW FBOX A40) sets your load requirement. Size the transformer so that load represents no more than 80% of its rating. A 1.2MW container needs at least a 1,500 kVA transformer (1,200 ÷ 0.8 = 1,500 kVA).
2. Grid voltage (primary): Confirm the voltage level of your utility interconnect. Common North American configurations: 12.47 kV, 13.2 kV, 13.8 kV, 24.94 kV, and 34.5 kV. Your transformer primary voltage must match.
3. Output voltage (secondary): The standard for most Bitcoin mining deployments is 415Y/240V. The 240V secondary voltage falls within the rated input range of virtually all ASIC PSUs from the S9 generation through most current models. 480Y/277V is only appropriate if your miners are rated for 277V input — and your transformer configuration accounts for all connected loads correctly. In a 480Y/277V deployment, miners connect phase-to-neutral (277V) while three-phase cooling loads connect phase-to-phase (480V); both come from the same transformer, but each load must be wired to the appropriate terminals. Most miners shipping today still use 240V PSUs; newer units like those shipping on current S21 models include PSUs (e.g., APW171215) rated for 277V, but this is not universal. Running a 240V-rated miner at 277V is out of manufacturer spec and can cause real operational problems. Confirm your exact miner model’s PSU rating before specifying transformer output voltage.
4. Lead time vs. deployment schedule: Custom transformer builds can take 12–40 weeks. If you have a fixed site-ready date, work backward from that date when selecting a supplier. In-stock suppliers can significantly compress timelines.

Bonus: harmonic derating and K-rating. High-density compute loads (both ASIC fleets and GPU clusters) draw non-sinusoidal current (switching power supplies create triplen harmonics), which generates additional heat in transformer windings. Transformers are rated for harmonic tolerance using a K-rating system; for Bitcoin mining and high-performance compute loads, specify a transformer with a K-13 rating or higher. A K-13 unit is designed to handle the harmonic content typical of these loads without accelerated thermal degradation. Work with your supplier to confirm both K-rating and derating factors. Undersizing or ignoring harmonic tolerance is one of the most common causes of premature transformer failure in mining and data center deployments.

Need Help Sourcing Transformers?

Luxor maintains active supplier relationships across companies listed above and can assist with transformer sourcing, spec review, logistics, and site planning for Bitcoin mining and data center infrastructure. Whether you're deploying a single container or scaling to 100MW+, reach out to our hardware team to get started.

If you’d like to learn more about Luxor’s full-stack Bitcoin mining services, please reach out to [email protected] or visit https://luxor.tech. 

About Luxor Technology Corporation 

Luxor delivers hardware, software, and financial services that power the global compute and energy industry. Its product suite spans Bitcoin Mining Pools, ASIC Firmware, Hardware trading, Hashrate Derivatives, Energy services, and a bitcoin mining data platform, Hashrate Index.

Disclaimer

This content is for informational purposes only, you should not construe any such information or other material as legal, investment, financial, or other advice.