Eaton MD51E99 Motor Drive Isolation Transformer - UL Listed
Part Number: MD51E99
Quick Summary
MD51E99 motor drive isolation transformer provides electrical isolation for drive systems in industrial applications. This unit protects sensitive inverter electronics from voltage transients and harmonics, helping extend component life and reduce unscheduled downtime. UL Listed certification underscores safety compliance, while the DT-3 dry-type design and WS39 weather shield enable reliable operation in demanding plant environments. The three-phase, 480 V primary/secondary configuration supports common motor drive architectures, and 51 kVA ratings tolerate mid-size loads with taps at +5% and -5% for field adjustments. For procurement teams, this transformer offers predictable performance, straightforward installation, and compatibility with Eaton's warranty framework, delivering long-term value in immediate retrofit or greenfield projects.
Product Information
Extended Description
MD51E99 Eaton: Drive Isolation Transformer, Ventilated, Dry Type Distribution, DT-3, Three-phase, PV: 480 delta, Taps: 1 at +5% FCAN, 1 at -5% FCBN, SV: 480 delta, 150°C, 51 kVA, Al windings, Frame: 914D, uses WS39
Product Name
Eaton Motor drive isolation ventilated transformer
Catalog Number
MD51E99
UPC
786680093371
Product Length/Depth
22 in
Product Height
39 in
Product Width
29 in
Product Weight
485 lb
Warranty
Eaton Selling Policy 25-000, one (1) year from the date of installation of the Product or eighteen (18) months from the date of shipment of the Product, whichever occurs first.
Certifications
UL Listed
Coil material
Aluminum
Design
DT-3
Frame
914D
Tap size
1 at +5% FCAN, 1 at -5% FCBN
Type
Dry Type Distribution, Drive Isolation Transformer
Frequency rating
60 Hz
Phase
Three-phase
Primary voltage
480 V
Secondary Voltage
480 V
Temperature rise
150 °C rise
Volt ampere rating
51 kVA
Weathershield
WS39
Commercial Distribution, Transformers, Volume 2, Tab 2
Eaton Specification Sheet - MD51E99
Selling Policy 25-000 - Distribution and Control Products and Services
Feature: 51 kVA rating with 480 V delta primary and 480 V secondary supports typical motor drive and VFD installations. Business Impact: Enables reliable power conditioning for mid-size drives, reducing overheating and extending drive life. Application: Suitable for manufacturing lines and process equipment where steady, clean power is critical. Feature: DT-3 ventilated dry-type construction with WS39 weather shield. Business Impact: Improves heat dissipation and protects the transformer in demanding environments, lowering maintenance cycles and downtime. Application: Indoor or protected outdoor environments in industrial facilities. Feature: Tap options at +5% FCAN and -5% FCBN. Business Impact: Field-adjustable voltage balance improves drive performance and protects downstream equipment from voltage excursions. Application: Plants facing voltage fluctuations or grid rubber-banding. Feature: Aluminum windings in frame 914D. Business Impact: Lightweight yet robust construction with reduced copper losses, supporting easier installation and long-term efficiency gains. Application: Retrofit projects in tight spaces or constrained plant footprints. Feature: 60 Hz three-phase operation with 51 kVA rating and 150°C rise. Business Impact: Delivers predictable, scalable performance for motor drives while meeting thermal design expectations, increasing overall system reliability. Application: Heavy-duty automation lines requiring consistent power quality. Feature: UL Listed certification and Eaton warranty framework. Business Impact: Demonstrates safety compliance and vendor-supported risk reduction, simplifying procurement and service planning. Application: OEM integrations, panel builds, and maintenance contracts in industrial settings.
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FAQs
MD51E99 is designed for three-phase 480 V power, providing isolation and clean power to motor drives and VFDs. The 51 kVA rating supports mid-size drive loads, while the +5% and -5% taps allow field voltage adjustments to maintain proper drive performance. Its aluminum windings and DT-3 dry-type construction ensure robust operation in industrial environments.
Plan for proper ventilation and clearance around the DT-3 enclosure, with mounting to a rigid surface suitable for a 485 lb assembly. The WS39 weather shield protects against environmental exposure, and the 914D frame fits standard Eaton mounting provisions. Verify 60 Hz, three-phase supply and ensure the taps are set per site voltage requirements.
Yes. The MD51E99 is rated for a 51 kVA load with a 150°C rise specification, supporting sustained operation in demanding drives and process equipment. Its DT-3 dry-type design, aluminum windings, and vented construction help manage heat, while the 480 V primary/secondary configuration aligns with common industrial motor drive architectures.
The MD51E99 is UL Listed, confirming compliance with recognized safety standards for electrical equipment. This certification supports safer installation, reduces compliance risk for audits, and aligns with Eaton’s warranty framework to provide coverage during the initial installation and operation period.
With a rugged three-phase, 60 Hz design and WS39 protection, MD51E99 delivers long service intervals and reduced maintenance needs. The UL Listed safety certification, warranty policy, and field-adjustable taps improve uptime and reliability, translating to lower maintenance costs and a faster payback in retrofit or new automation projects.