Unitron UDC-420M 28V DC Aircraft Rectifier (GPU)

Unitron UDC-420M
Unitron UDC-420MUnitron UDC-420MUnitron UDC-420MUnitron UDC-420M
Manufacturer: Unitron
Part Number: UDC-420M
Condition: New
Warranty: 3 Year Limited Warranty - View Details
✓ Worldwide shipping options available
✓ Manufacturer CofC always available at no cost after shipping
✓ Operating manuals available online for purchased equipment
Get Price & Order Now (it's quick & instant!)
Rating: 4.8 Based on 11 customer reviews
Ask Our Experts - We're here to help!
Live Chat | +1.252.585.4553 | Email

Get a Quote or Ask a Question

Simply fill out the form below and you will receive a quote via email shortly.
Company Name:
Phone: (optional)
Questions/Comments: (optional)
Unitron GPU Distributor

The new and reliable way to power your aircraft is the Unitron UDC-420M. It is a 28V DC rectifier with 425 amps continuous and 1600 amps max for use in the hangar or ramp environment. This unit operates on 3 phase input voltage (50 hz or 60 hz).

Highlights and Benefits

  • Digital touchscreen display
  • Over voltage protection
  • Under voltage protection
  • Voltage regulation to 28.5V DC +/- 0.5 V at all times
  • Output amperage can be limited to as low as 150 amps - fully adjustable
  • Line drop compensation - accounts for voltage drop in supply cable
  • Only unit to meet 18" fire code regulations
  • Half the weight of competitors

Standard Features

  • P55
  • Certified to UL 1012
  • Indoor/Outdoor (Hangar/Ramp)
  • Use Automatic Input Line Monitoring
  • 8000 Event Log / Diagnostics
  • TCP/IP/Ethernet Interface (Modbus)
  • 10% Power Regulation
  • Internal Communication Ports - USB, RJ45 (Ethernet), RS485 (Modbus), & RS232
  • External Communication Ports - RJ45 (Ethernet) & USB
  • Emergency Power "OFF" Switch
  • 18-Inch Hazard Area Clearance
  • Voltage and Current Monitoring
  • Elapsed Time Meter Access
  • Front Panel Voltage Adjust
  • Front Panel Summary Fault Indicators
  • Input & Output Cable handle
  • Input High Voltage Transient Protection
  • Output Current Limit Adjust from 150 to full rated current
  • Multi Language (Romanization) Display - English, French, German, Italian, Portuguese, Russian and Spanish, Others - Specify


  • Voltage: 208-240V and 380-480V, +/- 10%, 3 or 4 wire plus ground (Specify manual tap position at time of order)
  • Frequency: 50 - 60 Hz +/- 10%
  • Phase Rotation: Any
  • Protection: Over/undervoltage, loss of phase, overcurrent, short circuit. Voltage transient protection IAW IEEE C62.41.1, Location Cat. B/C
  • Inrush Current: No greater than 100% of full load current


  • Full Rated Load: 425 amps continuous
  • Engine Start Capacity (10% duty cycle): Adjustable up to 1600 amps for 35 seconds or 2000 amps for 30 seconds
  • Overload (10% duty cycle): 600 amps for 1 hour 1000 amps for 1 minute
  • Voltage: 28 VDC, 2 wire, grounded negative
  • Voltage Regulation
    • 100% continuous rated load and +/-10% input voltage ; +/- 0.5%
    • No load to rated load with nominal input voltage; AW ISO 6858 and MIL-STD-704F
    • Overload with nominal input voltage; See start mode curves
  • Voltage Adjust: 28 VDC +/- 10%
  • Current Limit Adjust: 150A to full rated current
  • Protection: Overload, short circuit, over voltage and safety disconnect
  • Power Regulation: 10%


  • Acoustical Noise: 65 dBA maximum at 5 feet (1.5m)
  • Temperature Range: -40 degrees C to +55 degrees C
  • EMI/RFI: Compatible with aircraft systems
  • Relative Humidity: 10 - 95%, Non-Condensing
  • Ingress of Water: Type 3RX, IP55

Mechanical Specs

  • Dimensions: See image on listing.
  • Weight: 340 lbs (154kg)
  • Enclosure: NEMA 3RX Corrosion Resistant
  • Cooling: Forced Convection


  • ISO 461-1/2 - Aircraft - Connectors for Ground Electrical Supplies
  • ISO 1540 - Characteristics of aircraft electrical system
  • ISO 6858 - Aircraft ground support electrical supplies
  • MIL-STD-704F - Aircraft electric power characteristics
  • MIL-STD-1472 - Human Engineering Design Criteria

Add-On Top Cable Rack Options Available for Longer Cable Lengths

  • CR 1-12 (12" cable rack) - 180' max (option) of combined cable
  • CR 1-9 (9" cable rack) - 120' max (option) of combined cable
  • Cable handle (standard in unit) 120' of combined cable
Alternate Models
400Alternative PN
600Alternative PN
Shipping Information
Pkg. 1 Weight780 lbs.
Pkg. 1 Dimensions56 in. x 53 in. x 52 in.
Pkg. 1 TypeCrate
Freight Class85
Freight NMFC62900
Schedule B8504409540
Customers who viewed this item also viewed:
50Hz/60Hz, 800A Continuous / 1600A Peak Start
60Hz - 600A Continuous / 2000A Peak Start - Single Output
50Hz/60Hz, 1000A Continuous / 2000A Peak Start
Customers who bought this item also bought:
Output cable - 20'
Input cable - 100'
Input Cable - 50'
UDC Cable Rack - 120' of combined (input and output) cable.
Unitron UDC Weather Proof Cover
Compatible Aircraft*
ATR42, 72
AdamA500, A700
AerospatialeNord 262
AgustaAW139 (AB139)
Airbus Military (CASA)212-100, 212-200, C-295, CN-235/HC-144A
BAeJetstream 31, Jetstream 41
Bell204, 205, 206B3, 206L4, 206LT, 212, 214, 214ST, 222, 230, 412, 427, 429, 430, CH-139, OH-58, TH-67, UH-1, UH-1H
Bombardier (Business)C-21, Challenger 300, Challenger 350, Learjet 23, Learjet 24, Learjet 31, Learjet 31A, Learjet 35, Learjet 45, Learjet 55, Learjet 60, Learjet 70, Learjet 75
Bombardier (Regional)CRJ100, CRJ1000, CRJ200, CRJ700, CRJ705, CRJ900, Dash 7, Dash 8-100, Dash 8-200, Dash 8-300, Dash 8-400
Britten NormanIslander/Trislander
Cessna402, Bravo, Caravan 208, Caravan 208B, Caravan 406, Citation 560 XL, Citation 560 XLS, Citation 650, Citation CJ1, Citation CJ2, Citation CJ3, Citation Encore 560, Citation I 500, Citation I/SP 501, Citation II 550, Citation III, Citation IV, Citation M2, Citation SII, Citation Sovereign 680, Citation Ultra 560, Citation V, Citation VI, Citation VII, Citation X 750, Mustang 510
DassaultFalcon 10-100, Falcon 20-200, Falcon 2000, Falcon 2000EX, Falcon 50, Falcon 50EX, Falcon 7X, Falcon 900, Falcon 900EX
EmbraerEMB-110, EMB-120, ERJ-135, ERJ-140, ERJ-145, Phenom 100, Phenom 300
EurocopterAS330 Puma, AS365N Dauphin, BK-117, BO-105
Fairchild/DornierMetro Merlin III, Metro Merlin IV
General DynamicsConvair 580, Convair 600, Convair 640
Hawker BeechcraftBeech 1900, Beech 99, Beechjet 400A, C-12, Diamond, Hawker 1000, Hawker 4000 (Horizon), HS-125 400 Series, HS-125 800 / 850 / 900 Series, King Air, Premier, T-1 Jayhawk, T-400, T-6A Texan II
IAIAstra, Westwind 1, Westwind 2
LockheedJetstar C-140
PiaggioP-180 Avanti
PilatusPC-12, PC-9
Saab2000, 340
Sabreliner40 Series, 60 Series, 70 Series
Shorts330, 360
SikorskyCH-148, H-92 Superhawk, S-65 (CH53, HH53, MH53, Sea Stallion), S-76 (AUH-76), S-92
Sino SwearingenSJ30-2
*This list is for general reference only and may not be entirely acurate for all aircraft. Please confirm all equipment meets the requirements of your aircraft with the owners/maintenance manuals prior to purchasing or using with your aircraft.

We service the UDC-420M and other items like it at our facility.

A few of the common services we offer for this item are:
• Overhaul / Refurbishment
• Troubleshooting
• Load Bank

We sell parts for the UDC-420M and other items like it at our facility. Not sure exactly what part you need? Just describe it or send us a photo and we will research it for you.

A few of the common parts we offer for this item are:
• AC Input Cable
• DC Output Cable
• DC Voltmeter
• DC Ammeter
• PDF Manuals

We provide short-term and long-term rentals for the UDC-420M. We will ship the item directly to you and arrange for pickup at the end of your lease.

Sell or Trade-In

We can purchase your used UDC-420M (or similar GSE items like it) and apply it as a credit for new GSE, or buy it outright directly.

Excellent power cart. Very clean DC output and stable voltage under load. Only disappointment is something better needed for winding up output cord. A side mounted rack would work much better to store the output cable assy.
Ours did not come with the top cable cage, which would have been nice to keep the input cable from falling off the top of the unit. Over all the unit works as expected. This is the second large end item we have purchased from CGSE, and my experience there will be more.
Great GPU, was exactly as described. I really like the controls on this units also. We use this on a Phenom 300 and have no issue with the proper voltage. It has very easy adjustments.
I have use many different types/sizes of GPU and this unit by far is the best. Our Line Services Department is growing and the new hires are very easily trained on proper use. We did not buy it with the top rack and that is the only option I wish we had purchased.
We are very happy with the unit. Our clients are also very impressed with it. It is being used in the hanger and also on the ramp very effectively.
We ordered two New units for our new flight department. From day one speaking with John I knew we had come to the right place. Our units arrived on time and in perfect condition.
This is a great power cart! It provides clean stable power for the most advanced aircraft. It's very well built and easy to use. I definitely recommend it.
Great for running A/C in hangar. Well made and supported. Front display provides tons of info. Cables wrap on handle making it easy to move. Using with Citation in private hangar.