Reliable 400hz Motor Drive for Helicopter Logging

A reliable 400hz motor drive was needed by the VIH Aviation Group to support their helicopter logging operations in Canada. VIH logging helicopters and crews operate in extreme weather, payload, and altitude conditions and needed a ruggedized 400hz aviation drive capable of supporting the hydraulic winch pods used in their fleet of heavy-lift helicopters.

What is Helicopter Logging?

Helicopter logging is an eco-friendly method of harvesting timber where individual trees are extracted from a forest by a helicopter, rather than by traditional ground-based methods such as

VIH Helicopter Logging
Photo: VIH Aviation Group

logging trucks or trains. The helicopter is equipped with a long cable and grappling hook, which is used to lift the logs out of the forest and transport them to a landing area where they can be loaded onto trucks or trains for transport to a mill. Harvested logs can weigh several thousands of pounds requiring substantial lift and winch power to raise and lower the logs. Helicopter logging is typically used in areas that are difficult to access by ground, such as steep terrain or rugged wilderness areas. It can also be used to selectively harvest valuable trees without causing damage to the surrounding forest.

Custom 400hz Drive for Hydraulic Winch Pod

Working with Kwak Aviation, LLC a manufacturer of aviation-based power systems, Invention House, LLC designed and manufactured a reliable 400hz motor drive capable of withstanding VIH’s extreme helicopter logging environment. The result is a reliable 400hz motor drive that meets military motor drive specs as well as these operating parameters:

• 3PD Input/Output Configuration: 3-phase input, 3-phase output.Picture of 20hp, 230 volt, 400 hz motor drive

• 230VAC – 65Amps rms (20hp) (10hp also possible)
• 50/60/400hz Output
• Flange for bulkhead mounting.
• Minimal cooling required – just 5 cfm across the heat sink fins.
• -40C to +55C temperature operating range
• 40g shock, 2grms vibration
• 10lbs total weight

Invention House Designs & Builds Custom 400hz Motor Drives

Invention House, LLC based in St Louis, MO has over 22 years of experience designing and developing custom single-phase and 3-phase VFD motor drives. Phil Langhorst, Invention House founder, and its president is a nationally recognized expert in power control and variable frequency drive design and manufacture, with special expertise in ruggedized and military spec motor drives. If your company is searching for a 400hz motor drive, we encourage you to contact Invention House today.

ruggedized 3-phase single-phase motor drives

Buying a Ruggedized Motor Drive: 3-Phase or Single-Phase

Buying a ruggedized electric motor drive, 3-phase or single-phase is no easy task these days.  Ruggedized motor drives fall within the overall category of variable frequency drives, but the similarity stops there. Ruggedized motor drives are designed to meet extreme operating conditions for temperature, altitude, shock, etc. Off-the-shelf motor drives are designed to meet general commercial and industrial operating conditions and to withstand common carrier and UPS shipping conditions.

Many companies go through numerous off-the-shelf drives before they realize they need a custom, ruggedized motor drive. The telltale signs of this are, failure during deployment, failure after traveling to a site, not starting in the winter, over-temperature tripping, downtime, sup-par operating performance, customer complaints, and more.  Finding the right motor drive to meet your demanding requirements can be a bit like looking for a needle in a haystack, but once you find the right manufacturer and right ruggedized motor drive, you will be rewarded with a lower total cost of ownership and higher customer satisfaction.

Ruggedized motor drives are custom variable frequency drives, designed to meet specific operating requirements. Examples of extreme motor drive requirements include:

  • Input/output frequencies up to 400Hz
  • Temperature range down to -40C, -40F. Up to   +55C, +60C, +65C
  • Continuous Vibration up to  2grms 
  • Shock (drop, near detonation) up to 40g  
  • Humidity up to 95% non-condensing
  • Stall prevention
  • Auto restart
  • Operation at Altitudes up to 14,000 ft.

Invention House builds American-made ruggedized motor drives that as a baseline are designed to meet one or more of the above specifications. These conditions also form the basis of military specification (mil-spec) motor drives. If a drive is built to meet mil-spec conditions, it will likely survive any industrial or commercial application.

Invention House ruggedized motor drives go one step further.  Our motor drives are built with integrated functionality to reduce the number of boards in a system, increasing reliability.  Onboard intelligence can take input from the command and from sensors to control not just the motor but also relays, and solenoids. In some cases, our drive is the only electronics necessary in the system. For example, one client needed a motor controller to maintain a constant air-fuel ratio at a high altitude. We designed a drive to do that and to test the performance of the ruggedized motor drive, the client strapped the running blower onto the back of a truck and drove it up Pikes Peak – the drive performed flawlessly and the blower speed automatically adjusted as the altitude increased. 

Another important factor when sourcing a ruggedized motor drive is the nature of the supplier.  Large motor drive suppliers and smaller divisions of a large, multinational company typically avoid custom motor drive work. Large companies need volume to keep their lines running. Smaller companies make the best independent motor drive manufacturers because they are more adept at meeting custom drive requirements.  In addition, when working with a smaller, independent motor drive manufacturer the buyer will have direct access to the drive designer and company leadership – a huge plus when trying to get your custom motor drive needs to be met. Invention House is just such a company with over 22 years of experience designing and manufacturing custom, ruggedized motor drives. Invention House meets Federal “small-company” purchasing requirements and our customers have the luxury of speaking directly with our drive engineers and leadership. If your company is searching for a ruggedized motor drive supplier, we invite you to connect with Invention House.

James Webb Telescope Shipping Container Supported by Invention House Motor Drive

James Webb Shipping Container STTARS
STTARS arrival at Ellingon Airport, TX.
Image Credit: NASA/Chris Gunn
Invention House is pleased to share the news that we provided custom 400 Hz electric motor drives for the protective container for the James Webb Telescope. The telescope was transported all over the world inside an enormous climate-controlled container, called STARRS (Space Telescope Transporter for Air, Road, and Sea).
The custom 400 Hz motor drive system supplied by Invention House allowed the container’s air conditioning system to operate anywhere in the world, on the road, and in the air. It accepted power supply at 50hz,60hz, or 400hz and delivered a steady 60hz to the compressor and fans. 
NASA had very tight specifications on the allowable temperature and humidity excursions within the container, also known as the James Webb Telescope “cocoon.”
  • The telescope, cocoon, air conditioners, and generators were mounted to a large custom flatbed semi-trailer.
  • On the highway, diesel generators provided 60hz power while in the air the C5’s turbine alternators provided 400hz power. The James Webb telescope traveled to Europe where the supply is 50hz.
  • Invention House provided 14kw and 2kw drives for the compressor and fans. The drives were custom engineered to withstand the vibration, temperature, and humidity extremes of being on a tractor trailer and in flight.
The red arrow shows the location of Invention House 400 Hz drives on the James Webb STTARS container.
The system was in service for over 4 years and traveled over 15,000 miles (24,160 km) with several stops in the US, Europe, and finally landing in French Guyana South America from where the James Webb Telescope was launched. The rocket was an Ariane 5 from the European Space Agency. Rockets with their heavy payloads are often launched from near the equator where the surface of the earth is spinning fastest, giving the rockets an extra boost.
NASA reported no issues with the system.

When does developing a custom VFD make sense?

Variable frequency drives are now ubiquitous in the motor control industry, with dozens of large to small-scale players offering ready-built products.  With just a  few quick Google searches you can find drives to meet almost any need.  However, like the proverbial square peg in a round hole, sometimes an off-the-shelf drive just doesn’t fit the use case.

To help motor control engineers determine when developing a custom VFD makes sense we have created a Custom VFD Checklist that outlines the considerations we work thought when consulting with our clients.   While we specialize in building custom AC motor drives, going the custom route is not our first choice if it can satisfactorily avoided.

Download our FREE Custom VFD Checklist NowCustom variable frequency drive checklist

There are trade-offs for going down the custom path. You get exactly what you need, but it will typically cost more than off-the-shelf, unless substantial volumes are involved. Cost factors may include non-recurring engineering costs (NRE), UL certification costs if required, packaging costs, and/or higher per-unit costs. There is also a timing factor; anything which must be first engineered and developed naturally takes longer than pulling something off the shelf.  Other considerations include ownership of intellectual property associated with a new drive, assuming it is truly a one-off design.

Case Study – Oil Burner:  Recently Invention House created a custom VFD for an OEM that manufactures oil burners used in HVAC applications.  Our client needed a 110v single phase drive capable of 80Hz to drive the combustion fan of a portable oil burning heater. The burner is a world-ready unit that must be able to operate between -40 and +130F(55C). In addition, it had to be very rugged to withstand truck transport and rough delivery conditions. Invention House designed a single board drive in an open 3″x 2″x 7″ aluminum frame. The drive responds to commands for high and low fire rates (100,000/200,000 btu/hr). It has several on-board relays to energized the fuel solenoids and the fresh air blower. The drive has custom adjustable relay timing to avoid flame outs during transitions and to avoid blasts of cold air to the user. The drive’s main function is to create the correct frequency for the combustion fan. This is done using an on-board altitude sensor that allows the drive to maintain the correct air /fuel ratio. There is also a on-bard tilt sensor for safety. These sensors would have been difficult to do using convention PLC’s and a conventional solution would never have fit in the necessary space. The true befit of the combustion solution came at then end of the development when the specification suddenly changed wanting combustion at 14,000 ft. This required 120hz operation and more voltage. Invention House simply reprogrammed the drive for 120hz and designed an small transformer to boost the input voltage to 160vac. The product was successfully tested at the top of Pike’s Peak and has endured operating many thousand of hours in harsh conditions.

As the above case study illustrates, if your situation is one where unique factors are involved, such as those outlined in our Custom VFD Checklist, then going down the custom path will be a rewarding one.   You end up with a drive tailored to your specific requirements and in the size and shape that fits your design specs. In addition, because the drive is tailored to your product’s specs, there is usually less installation time as the unit comes programmed, tested, and with wiring terminals and other factors that make installation more of a plug and play install.

One remaining important factor to share…gaining a competitive edge.  If your company is competing with similar products and all those products employ off-the-shelf drives, you can gain a competitive edge by going the custom route. Your product will be unique and have a performance curve that beats the competition and helps create stronger vendor-customer bonds.

In summary, don’t be afraid to look at developing a custom variable frequency drive, especially if your product meets one of the 5 key custom VFD decision factors outlined in our free guide.  If you have that round hole situation, build a round drive. You’ll be more satisfied in the end and so will your customers.