28VDC/400Hz Combi Static Frequency Converter

Q: What is a 28V DC / 400Hz combi static frequency converter used for?

A 28V DC / 400Hz combi static frequency converter is used to supply both regulated 28V DC power and 115/200V AC 400Hz power from a standard mains supply. It is commonly used for aircraft ground power, avionics testing, maintenance operations, and production line testing where both DC and AC aircraft power are required.

Q: Can the DC and AC outputs be used at the same time?

Yes. The combi static frequency converter is designed to provide simultaneous 28V DC and 400Hz AC outputs, allowing multiple aircraft systems or test equipment to be powered at the same time. This reduces the need for separate power units and improves operational efficiency.

Q: What input power supply does the converter require?

The unit accepts a standard 50Hz or 60Hz mains supply, depending on configuration. Input voltage and phase options can be specified to suit site requirements, including single-phase or three-phase supplies.

Q: Is the output suitable for sensitive avionics and test equipment?

Yes. The converter uses advanced IGBT-based solid-state inverter technology to deliver clean, low-distortion power with precise voltage and frequency control. This makes it suitable for sensitive avionics, aircraft electrical systems, and laboratory test environments.

Q: What protection features are included?

The system includes comprehensive built-in protection such as overload protection, short-circuit protection, over-voltage protection, and over-temperature monitoring. These features help protect both the converter and connected equipment during operation.

Q: Is the converter available as a mobile or fixed unit?

The 28V DC / 400Hz combi static frequency converter is available in both fixed installation and mobile configurations. This makes it suitable for use in aircraft hangars, maintenance facilities, production areas, and flight line support where flexibility or portability is required.

Q: What are the advantages over rotary converters?

Compared to traditional rotary converters, the solid-state combi converter offers quieter operation, higher energy efficiency, reduced maintenance requirements, and improved reliability. Its compact design also saves valuable floor space in hangars and test areas.

The 28VDC/400Hz Combi Static Frequency Converter is a compact, solid-state power conversion system designed to provide both regulated 28VDC and 115/200V AC power, 400Hz outputs from a standard 50Hz or 60Hz mains supply. It combines two essential aircraft ground power functions, DC and AC supply into a single, integrated unit for enhanced efficiency, reliability, and space savings.

Utilising advanced IGBT-based inverter technology, the 28VDC/400Hz Combi Static Frequency Converter delivers clean, stable, and low-distortion power suitable for aircraft, avionics testing, and maintenance operations. The unit ensures precise voltage and frequency control under varying load conditions, with built-in protection against overload, short circuit, over-voltage, and over-temperature.

The combi converter is available in fixed or mobile configurations, making it ideal for aircraft hangars, maintenance facilities, production lines, and flight line support. Its modular solid-state design ensures quiet operation, minimal maintenance, and high energy efficiency compared to traditional rotary converters.

Click here for a sample specification

Features:

Combined 28VDC and 115/200V AC, 400Hz outputs
Static (solid-state) design – no moving parts, low maintenance
Input: 3-phase, 50Hz or 60Hz mains power
High efficiency and low total harmonic distortion (THD)
Precise voltage and frequency regulation under varying loads
Digital control and monitoring with user-friendly interface
Comprehensive protection: overload, short-circuit, overtemperature
Compact, lightweight, and mobile-friendly configuration options
Suitable for aircraft ground power, avionics testing, and manufacturing

Applications:

The 28VDC/400Hz Combi Static Frequency Converter is designed for environments where simultaneous aircraft-standard AC and DC ground power is required from a single solid-state source.

Common applications include:

Aircraft ground power support during maintenance, servicing, and pre-flight preparation
Avionics workshops and aerospace test benches requiring stable 115/200V 400Hz AC and 28VDC output
MRO hangars needing compact combined ground power without separate converter systems
Aircraft production lines and final integration stations prior to engine-driven generator commissioning
Aerospace component manufacturing and acceptance testing of LRUs and control equipment
Defence aviation maintenance facilities operating mixed aircraft electrical support platforms
Mobile or semi-fixed flight line service locations where flexible aircraft ground power supply is required

This type of combined 28VDC and 400Hz frequency converter is particularly useful where space, installation complexity, or infrastructure limitations make separate AC and DC ground power units impractical.

Our Combi Static Frequency Converters are designed specifically with your requirements in mind. For a quote specific to your needs please provide us with the following:

If you have space and weight restrictions please let us know, we are able to provide bespoke cases to fit most environments.

Available options:

IP54 Rated cases for rugged outdoor use, Marine and Avionic environments. Vital protection against Humid environments, Condensation, Salt Spray, Water ingress and dust.
Additional conformal coating of internal PCB boards and electronic parts to provide added protection in harsh environments
19″ Rack Mount options for smaller models
12 & 18 Pulse Rectiifiers available for increased harmonic performance
Remote control watchdog for larger models: For models typically over 50kVA, we can provide a watchdog system that provides real time information on faults via an SMS service, stores data history, enables remote operation and automatic restart availability.
Cables and terminations for various aircraft types
Trolleys and rubber wheels with swivel tow bar for ease of movement. A fully mobile GPU unit suitable for MRO sites, Airfields, Hangers and Military Bases where mobility is a key requirement

Popular configurations

We have a variety of models available, please see below for some popular configurations. Please note: customers may request alternative voltages and frequencies as required, below are examples only.

Model	Capacity	Current Rating	Input	Output	Dimensions	Weight
PXe-3310001.6T 3ph In/3ph Out/1ph Out	1.6kVA	Output 1 – 16A per phase @ 20.8V Output 2 – 5.2A @ 115V	380V (L-L) ±10% \| 50Hz \| 3 Phase +N	Output 1 – 20.8V (L-N)/36V (L-L) \| 3 Phase +N (1kVA) \| 1000Hz Output 2 – 115V \| Single Phase +N (0.6kVA) \| 1000Hz	430x600x700mm	64kg
PXe-3330014.5T 3ph In/3ph Out/3ph Out	10kVA & 4.5kVA	Output 1 – 28A per phase @ 115V Output 2 – 5.9A per phase @ 254V	440V (L-L) ±10% \| 60Hz \| 3 Phase	Output 1 -0/200V (L-L) 115V (L-N \| 3 Phase +N (10kVA) \| 400Hz Output 2 – 254V (L-N)/440V (L-L) \| 3 Phase +N (4.5kVA) \| 400Hz	600x530x1650mm	220kg

Model

Capacity

Current Rating

Input

Output

Dimensions

Weight

PXe-3310001.6T

3ph In/3ph Out/1ph Out

1.6kVA

Output 1 – 16A per phase @ 20.8V

Output 2 – 5.2A @ 115V

380V (L-L) ±10% | 50Hz | 3 Phase +N

Output 1 – 20.8V (L-N)/36V (L-L) | 3 Phase +N (1kVA) | 1000Hz

Output 2 – 115V | Single Phase +N (0.6kVA) | 1000Hz

430x600x700mm

64kg

PXe-3330014.5T

3ph In/3ph Out/3ph Out

10kVA & 4.5kVA

Output 1 – 28A per phase @ 115V

Output 2 – 5.9A per phase @ 254V

440V (L-L) ±10% | 60Hz | 3 Phase

Output 1 -0/200V (L-L) 115V (L-N | 3 Phase +N (10kVA) | 400Hz

Output 2 – 254V (L-N)/440V (L-L) | 3 Phase +N (4.5kVA) | 400Hz

600x530x1650mm

220kg

Technical Specification

Capacity
Single Phase Output	kVA Ratings: 0.5kVA, 1kVA, 3kVA, 5kVA, 10kVA, 15kVA, 20kVA, 30kVA, 50kVA, 60kVA, 75kVA, 100kVA, 150kVA, 200kVA
Three Phase Output Versions	kVA Ratings: 1kVA, 3kVA, 6kVA, 9kVA, 15kVA, 20kVA, 30kVA, 45kVA, 60kVA, 100kVA, 150kVA, 200kVA, 300kVA, 400kVA, 500kVA~2000kVA (Select One kVA)
Input
Single Phase (Select One Individual Voltage)	110Vac ±10%, 115Vac ±10%, 120Vac ±10% 127Vac ±10%, 220Vac ±10%, 230Vac ±10%
Three Phase (Select One Individual Voltage)	115-127 (L-N) / 200-220V (L-L) ±10%, 220-240 (L-N) / 380-415V (L-L) ±10%, 3 Phase 4 Wire 440V (L-L) ±10%, 480V (L-L) ±5%, 3 Phase 3 Wire
Frequency	50Hz/60Hz ±5%, 400Hz (Optional)
Power Factor	≥ 0.8 (standard type) ≥ 0.9 (optional type, 12 pulse)
Output
Single Phase (Select One Individual Voltage)	Fixed: 110V, 115V, 120V, 127V, 220V, 230V, 240V Adjustable: 0~150Vac / 0~300Vac
Three Phase (Select Two Individual Voltages)	Fixed: 115/200V (L-N/L-L), 120/208V (L-N/L-L), 127/220V (L-N/L-L), 220/380V (L-N/L-L), 230/400V (L-N/L-L), 240/415V (L-N/L-L), 254/440V (L-N/L-L), 277/480V (L-N/L-L), 3 Phase 4 Wire Adjustable: 0~260V (L-N) / 0~520V (L-L), 3 Phase 4 Wire
Frequency	Fixed: 50Hz, 60Hz, 100Hz, 200Hz, 45-200Hz (adjustable) Optional: 400Hz, 40Hz~500Hz (adjustable), 16.67Hz, 25Hz, 50Hz, 60Hz, 400-1000Hz
Voltage Accuracy	≤ ±1% FS (Full Scale)
Frequency Accuracy	≤ ±0.1% FS (Full Scale)
Total Harmonic Distortion	THD ≤ 3% @ linear load, pure sine wave output
Crest Factor (Pk/rms)	3:1
Overload	100% for continuous, 101-200% shut down in 200mS
Interface	None for standard units, RS232C/RS485/GPIB (Optional)
Protection	Over-current, over-load, over-voltage, over-temp, short circuit, alarm and indicators
Enclosure IP Rating	IP22 (Standard), IP32, IP54 (Optional). Special enclosure options available
LED/LCD Display	Digital frequency meter Digital voltage meter Digital current meter Digital power/PF meter
Connectors	Hard-wire terminals, EN60309, MIL-STD, Or client choice
Operating conditions
Temperature	Operation: -10℃~55℃ Ambient: -10℃~45℃
Noise	≤ 65dB at 1 meter EN 55022, IEC1000-4
Humidity	10~90% non-condensing
Cooling	Variable speed fan, filtered air intake in base, exhaust at rear
Altitude	≤ 1800m
Castors or Feet	0.5-3kVA have rubber feet and lifting handles, 4kVA+ have castors with front brakes. A/Vs or feet optional
CE	CE Marked
Reliability and Efficiency
Mean Time Between Failure (MTBF)	50,000Hrs
Mean Time To Restore (MTTR)	< 30 min
Overall Efficiency	≥ 85%
Standards
GB50054-95, GB 50150-1991, GB 50150-2006, GB 50171-1992, GB/T 16935.5-2008, GB/T16935.4-2011
EN IEC61000-3-2, EN 61000-3-3, EN55032, EN55035, MIL-STD-1399, MIL-STD 461, MIL-STD704, STANAG 1008
For more information and support, please feel free to contact us