Dry-Type Transformers
AMP Magnetics is an independent manufacturer’s representative for leading domestic builders of standard and custom-engineered dry-type power transformers.
Custom Sizing for Non-Linear and Severe-Duty Loads
Standard catalog transformers often fail prematurely when exposed to non-linear harmonic heating from variable frequency drives, SCR power supplies, and automated machinery. As a manufacturer’s representative, AMP Magnetics connects OEMs and facility operators with plants capable of custom core-and-coil designs tailored to your thermal, electrical, and dimensional boundaries.
Whether your project requires high K-factor harmonic mitigation, electrostatic shielding to attenuate common-mode noise, or retrofit enclosures engineered to drop onto existing concrete pads, we guide your job from initial spec review to delivered equipment.
Dry-Type Transformer Capabilities & Design Options
Our represented manufacturers engineer units across the following operational profiles:
| Transformer Classification | Typical kVA Range | Voltage Classes | Key Engineering Attributes |
|---|---|---|---|
| Drive Isolation Transformers | 15 kVA – 1,500 kVA | Up to 600V Primary & Secondary | Braced for mechanical shock of frequent motor starts; electrostatic copper shield between windings to isolate common-mode electrical noise. |
| K-Factor Harmonic Rated | 30 kVA – 2,500 kVA | 208V, 240V, 480V, 600V | Engineered for high harmonic neutral currents (K-4, K-13, K-20, K-30); 200% rated neutral bus bar, transposed conductors to reduce eddy losses. |
| General-Purpose Isolation | 15 kVA – 3,000 kVA | 600V Class / 5 kV Class | Step-up / step-down plant distribution; copper or aluminum windings; 220°C insulation systems with 150°C, 115°C, or 80°C temperature rise options. |
| Medium-Voltage Dry-Type | 225 kVA – 5,000+ kVA | 2.4 kV, 4.16 kV, 12.47 kV, 13.8 kV, 34.5 kV | VPI (Vacuum Pressure Impregnated) or Cast Resin; indoor substation integration or outdoor weatherproof padmount enclosures. |
| Custom & Retrofit Enclosures | All Sizes | Custom Tap Configurations | NEMA 1 (indoor), NEMA 3R (outdoor rainproof), NEMA 4X (304/316 stainless steel for chemical/marine), custom dimensions to match legacy footprints. |
Temperature Rise Sizing
Specifying an 80°C or 115°C temperature rise over a 220°C class insulation system yields significantly lower operating losses, extended service life, and built-in continuous overload capability.
Electrostatic Shielding
A grounded copper foil shield between primary and secondary windings attenuates line transients and high-frequency noise from passing into sensitive downstream control systems.
Thermal Sensor Options
Units can be specified with embedded winding temperature detectors (RTDs, thermocouples, or thermistors) wired to terminal blocks for SCADA and PLC integration.
Have an Active Transformer Specification?
Send your single-line diagram, kVA requirement, primary/secondary voltages, and dimensional requirements to our desk for quotation coordination.
Submit Transformer RFQQuestions we get asked about Dry-Type Transformers
What is the difference between a drive isolation transformer and a general-purpose transformer?
A drive isolation transformer is built specifically for rectifier load. It tolerates the harmonic heating and DC component that a drive front end imposes, and is usually supplied with an electrostatic shield between windings. A general-purpose transformer on the same duty runs hot well below its nameplate kVA and suffers shortened insulation life.
How do I know which K-factor rating I need?
K-factor is determined by the harmonic spectrum of the load, not by the transformer. K-4 generally suits up to roughly 35 percent non-linear load, K-13 up to about 50 percent, and K-20 up to about 75 percent. Where a power quality measurement exists, calculate K from the measured spectrum rather than estimating, because over-specifying carries real cost in size and weight.
What lead times should I plan for on a custom dry-type transformer?
Standard catalogue units are generally shorter, while custom core-and-coil designs, non-standard voltages, and special enclosures extend considerably. On projects where the transformer sits on the critical path, engaging at design stage rather than at purchase order stage is the single most effective schedule protection available.
Can a transformer be supplied for outdoor or washdown installation?
Yes. NEMA 3R is the normal outdoor choice and is ventilated, which suits a self-cooled dry-type unit. Washdown and corrosive environments require NEMA 4 or 4X, which are sealed and therefore change the thermal design — expect a physically larger unit, a lower temperature rise class, or forced cooling. Specify the stainless grade explicitly in chloride environments.
Does AMP Magnetics stock transformers?
No. AMP Magnetics is an independent manufacturer's representative. It does not manufacture, stock, warehouse, or take title to product. It matches your specification to a qualified manufacturing plant and coordinates the job from quotation through delivery.