Eaton MD440D79CU Motor drive isolation transformer - UL
Part Number: MD440D79CU
Quick Summary
Eaton MD440D79CU motor drive isolation transformer delivers clean, three-phase power for demanding industrial drives and automation systems. Engineers often wrestle with drive-side disturbances and voltage dips that interrupt VFD performance and reduce uptime. This unit carries UL Listed safety certification and follows a DT-3 dry-type distribution design with copper windings for reliability in harsh industrial environments. With a 440 kVA rating, 480 V primary (delta) and 480Y/277 V secondary, plus two taps at ±2.5%, it supports flexible installation and precise voltage control. The WS35 weather shield and ventilated construction simplify outdoor or harsh indoor applications, while its rugged frame, 919E, helps isolate the drive from mechanical loads and vibration. Ideal for OEMs and integration teams seeking robust power conditioning.
Product Information
Extended Description
MD440D79CU Eaton: Drive Isolation Transformer, Ventilated, Dry Type Distribution, DT-3, Three-phase, PV: 480 delta, Taps: 2 at +2.5% FCAN, 2 at -2.5% FCBN, SV: 480Y/277, 150°C, 440 kVA, Cu windings, Frame: 919E, uses WS35
Product Name
Eaton Motor drive isolation ventilated transformer
Catalog Number
MD440D79CU
UPC
786680071195
Product Length/Depth
36.23 in
Product Height
75 in
Product Width
44.2 in
Product Weight
3966 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
Copper
Design
DT-3
Frame
919E
Tap size
2 at +2.5% FCAN, 2 at -2.5% FCBN
Type
Dry Type Distribution, Drive Isolation Transformer
Frequency rating
60 Hz
Phase
Three-phase
Primary voltage
480 V
Secondary Voltage
480Y/277 V
Temperature rise
150 °C rise
Volt ampere rating
440 kVA
Weathershield
WS35
Feature: Dry-type DT-3 construction with copper windings. Business Impact: Reduces risk of oil leaks and simplifies maintenance while delivering reliable insulation in rugged environments. Application: Suitable for dry-type distribution in motor control centers and drive isolation installations. Feature: Ventilated cooling design. Business Impact: Enhances thermal performance under continuous load, reducing temperature rise and extending component life. Application: VFD and motor drive systems operating in factories with limited ambient cooling. Feature: 440 kVA rating with 480 V delta primary and 480Y/277 V secondary. Business Impact: Supports high-power drive isolation with precise voltage translation, improving system stability. Application: Large motor drives and automated lines requiring consistent secondary voltage. Feature: Dual taps at +2.5% and -2.5%. Business Impact: Enables voltage tuning to compensate for line fluctuations, improving drive performance. Application: Plants with long feeders or variable supply conditions. Feature: WS35 weather shield and rugged 919E frame. Business Impact: Enables outdoor or harsh indoor installations with robust protection and easy mounting. Application: Outdoor substations, distribution panels, and OEM enclosures. Feature: Three-phase, 60 Hz operation with 150°C rise. Business Impact: Aligns with standard industrial power systems, ensuring compatibility with contemporary equipment and safe thermal margins. Application: Industrial automation, packaging lines, and heavy manufacturing.
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FAQs
Mount the unit using its 919E frame with the provided mounting provisions, ensuring proper ventilation. Connect the primary to 480 V delta, and the secondary to 480Y/277 V. Use the two taps at +2.5% and -2.5% to fine-tune voltage under feeder and load conditions. Verify WS35 shield placement for outdoor or harsh indoor installations and follow the Eaton installation datasheet for clearances and cooling requirements.
The transformer is 440 kVA, three-phase, with a 480 V primary (delta) and 480Y/277 V secondary, rated for 60 Hz operation and a 150°C rise. It uses copper windings, is dry-type DT-3, and features dual taps at ±2.5%. Frame is 919E, with WS35 weather shielding for protection in rugged environments.
Yes. The MD440D79CU is specifically designed for drive isolation in motor control centers and VFD installations, providing transient suppression and noise isolation to improve drive performance, reduce EMI, and increase system uptime in automated manufacturing environments.
The MD440D79CU carries UL Listed certification, confirming compliance with safety standards for industrial electrical equipment. Eaton provides a one-year warranty from installation or eighteen months from shipment, whichever occurs first, offering protection against manufacturing defects during early use.
WS35 shielding enables reliable outdoor or harsh indoor use, while the ventilated dry-type design reduces maintenance and leak risks. For ROI, ensure appropriate ventilation, correct tap setting for site voltage, and compatibility with the 919E frame. Proper installation minimizes downtime, extends service life, and improves protection for high-value drive systems.