01What a 3750 kVA Transformer Is Used For
A 3750 kVA transformer is a substantial three-phase unit. The rating is included in the preferred continuous three-phase ratings listed in IEEE C57.12.00-2015, Table 2, at a 65°C average winding rise. Custom ratings also exist, so the nameplate—not a catalog assumption—confirms the unit’s actual rating and configuration.
At this capacity, common applications include large industrial and renewable-energy service, large unit substations, battery energy storage systems (BESS), and data-center electrical infrastructure. The transformer may be a new-surplus project leftover, an installed unit being replaced, or a spare held for a facility or project.
- Check whether 3750 kVA is the continuous rating or one of several staged ratings.
- Confirm phase, frequency, voltage, cooling, and connection from the nameplate.
FLAFull-Load Amps for a 3750 kVA Transformer
Rated full-load current at common California voltages. Single-phase: amps = kVA × 1000 ÷ volts. Three-phase: amps = kVA × 1000 ÷ (1.732 × volts). Use the nameplate voltage of your unit.
| Phase | Voltage | Full-load amps |
|---|---|---|
| Three-phase | 480 V | 4,511 A |
| Three-phase | 4.16 kV | 520 A |
| Three-phase | 12 kV | 180 A |
| Three-phase | 12.47 kV | 174 A |
| Three-phase | 20.78 kV | 104 A |
| Three-phase | 34.5 kV | 62.8 A |
| Three-phase | 66 kV | 32.8 A |
02Common 3750 kVA Transformer Types and Configurations
Three-phase pad-mount transformers are one possible configuration at this size. They can serve sites with outdoor, compartmentalized distribution equipment; the actual primary and secondary voltage, switching, protection, and enclosure details vary by design. See examples of [three-phase pad-mount transformers](three-phase pad-mount transformers).
Other configurations in this rating include medium-voltage dry-type VPI units, cast-resin transformers, and secondary unit substations close-coupled to switchgear. Solar inverter step-up and BESS transformers are also represented at this capacity. A 3750 kVA pole-mount unit is not a typical configuration; identify the actual construction rather than relying on the rating alone. Compare [medium-voltage dry-type transformers](medium-voltage dry-type transformers), [cast-resin transformers](cast-resin transformers), and [unit substation transformers](unit substation transformers).
03Typical Voltages and California Project Loads
Available voltage combinations depend on the transformer’s role and the site’s electrical system. A 3750 kVA unit may step medium voltage down to a facility distribution voltage, or step up the output of an inverter or other generation equipment. For a pad-mounted unit, primary-voltage classes used in California include 12 kV, 16 kV, 21 kV, and 34.5 kV; not every configuration is suitable for every utility or project.
California systems vary by utility and location. PG&E documents 12 kV and nominal 21 kV distribution, while SCE has 4 kV, 12 kV, and 16 kV distribution systems, among others. Industrial facilities commonly use three-phase secondary systems such as 480Y/277 V or 208Y/120 V, but the transformer’s actual nameplate and project requirements control. Do not assume a nominal voltage matches a specific site without checking the serving utility and electrical design.
At 3750 kVA, the unit may support large plant loads, a utility-scale renewable or storage project, or a large unit substation. To evaluate suitability, compare the nameplate voltages and connection with the site design, including whether the unit is intended for step-up or step-down service.
04How to Read the 3750 kVA Full-Load Amps Chart
The full-load amps chart rendered on this page shows calculated three-phase current at the listed voltages. Read across the row for the applicable line-to-line voltage, then use the amp value as the transformer’s approximate full-load current at that voltage. Higher voltage corresponds to lower current for the same kVA rating.
These chart values help with an initial comparison; they are not a substitute for the nameplate, engineering calculations, or protection and conductor coordination. Verify whether the chart’s voltage matches the unit’s actual winding voltage and connection. For a refresher on the relationship between kVA, voltage, and current, use this [transformer kVA and amps guide](transformer kVA and amps guide).
05Physical Size, Weight, and Removal Planning
A 3750 kVA transformer is substantially larger and heavier than a typical building distribution transformer, but there is no single size or weight for this rating. Dimensions and total weight vary by manufacturer, insulation type, voltage class, cooling design, enclosure, and accessories. A dry-type unit, pad-mount, and substation assembly can have very different footprints and handling requirements.
For an initial review, share nameplate weight fields, overall photographs, and any available drawings or shipping records. For a substation or unit-substation transformer, note whether radiators, fans, switchgear, or other components are part of the sale. Do not attempt to move or access restricted equipment; the owner’s qualified electrical contractor or serving utility handles electrical isolation and disconnection.
- Identify the equipment location and available site access.
- Include any known rigging, loading, or freight constraints.
- Clarify which accessories and related equipment are included.
06What Affects the Value of a Used 3750 kVA Transformer
A used 3750 kVA transformer’s value depends on its complete specification, condition, and likely reuse options. Primary and secondary voltages, connection, impedance, BIL, cooling class, temperature rise, and winding material help establish what applications the unit can serve. Commonly usable voltage combinations can affect buyer interest, but no single rating guarantees an offer.
Age, manufacturer, leaks or visible damage, missing parts, and the availability of test reports also matter. For liquid-filled units, fluid type, quantity, and PCB records are relevant; dry-type units should be identified by insulation and cooling details. Factory test reports, oil test or DGA records, insulation resistance, and turns-ratio results can help document condition. Sellers should rely on testing, documentation, and qualified environmental professionals for PCB or environmental determinations.
New-surplus condition, quantity, accessories, ownership authority, and site access can affect the review as well. California Transformer Buyer considers each unit based on the information available; reviewing it costs nothing and does not obligate you to accept an offer. Read more about [factors that affect used transformer value](used transformer value factors) or about selling [surplus transformers](surplus transformers in California).
07What to Send California Transformer Buyer for an Offer
For a useful first review, send clear nameplate photos and overall photos taken from a safe position, of equipment you are authorized to access. Include the number of units, California location, known condition, and whether the transformer is used, spare, decommissioned, or new-surplus. You can [send transformer details for an offer](sell your transformer) or text photos to Rocky at (951) 403-5738.
The nameplate information that helps most includes manufacturer, serial number, year, kVA, phase, frequency, high- and low-voltage ratings, connections, taps, impedance, BIL, cooling class, temperature rise, and fluid type if applicable. Add the weight, winding material, PCB label, test reports, and records that are available. Do not open compartments, drain fluid, or disconnect equipment to obtain details.
Rocky may ask follow-up questions about test reports, ownership, environmental records, and site access. If the unit is a fit, the written offer states the price, what is included, who handles loading or rigging and freight, and payment terms and timing. Pickup is scheduled according to the terms agreed in writing. Contact [California Transformer Buyer for a review](request a transformer offer) for the next step.
kVANearby Transformer Sizes We Buy
FAQ3750 kVA Transformer FAQ
Can I sell a 3750 kVA transformer if I do not know its exact voltage?
Yes, you can ask for a review with the information you have. Send clear photos of the nameplate and overall unit, along with its location, quantity, and known condition. The nameplate usually provides the primary and secondary voltage, connection, and other details needed to identify the configuration. Do not open or access equipment to find missing information; a qualified professional should handle any inspection.
Does California Transformer Buyer consider both liquid-filled and dry-type units?
The 3750 kVA configurations in scope include medium-voltage dry-type VPI and cast-resin units as well as pad-mount and substation types. Send the construction type, nameplate, and condition details so the unit can be reviewed accurately. For a liquid-filled transformer, include any available fluid and PCB records. Environmental status should be established through documentation, testing, and qualified environmental professionals.
Is 3750 kVA the same as 3000 kVA?
No. They are different ratings, and the nameplate identifies the specific unit. The verified IEEE C57.12.00-2015 preferred three-phase rating series includes 3750 kVA; 3000 kVA is also a common catalog or commercial size, but it is not in that verified Table 2 series. Custom ratings exist, so a seller should provide the actual nameplate rather than infer a rating from appearance.
What if my 3750 kVA transformer has no recent test reports?
You can still submit the unit for review. Say which records are available and which are not, and include clear nameplate and overall photos. Test documentation can help a buyer assess condition, but it should not be invented or represented as current if it is not. Any additional inspection or testing should be arranged through qualified electrical professionals, not by opening or handling the equipment yourself.
Can a property owner sell a transformer that belongs to the serving utility?
A seller must own the transformer or have authority to sell it. Equipment located on private property may still be utility-owned, and the property owner cannot sell it without the required authority. If ownership is unclear, check the purchase, project, or utility records before requesting an offer. Include ownership information with the unit details so the sale can be reviewed appropriately.
What pickup and freight details are settled before removal?
If an offer is made, its written terms state what equipment is included, who handles loading or rigging and freight, and the payment terms and timing. Site access and removal complexity can affect planning, so describe known constraints and whether the transformer is installed or already removed. Electrical isolation and disconnection must be performed by the owner’s qualified electrical contractor or serving utility.