Zero-Cogging Motors For Precision Underwater Applications

Seventy percent of the Earth’s surface is covered in water. Whether for defense, industry or exploration, the demand of underwater systems, such as manned submersibles, Remotely Operated Vehicles (ROVs), and Unmanned Underwater Vehicles (UUVs) is a market that is expected to grow to more than $10 billion by the 2030s, according to Emergen Research.  These underwater platforms of all forms stand to leverage the benefits of ThinGap’s high efficiency motor kits. With critical functions such as robotic actuation and quiet, yet highly efficient propulsion, ThinGap’s motors continue to find a home in marine and subsea applications.

An emerging use for ThinGap’s brushless DC motors is marine propulsion. ThinGap motors are ideal for underwater direct drive thrusters because of a high torque-to-diameter ratio. ThinGap recently delivered a floodable motor assembly based off its LS Series to a defense customer for a UUV application. With no gearbox, there are no drivetrain losses, enabling lower assembly weight, increased torque, and greater reliability.

As a flooded motor, ThinGap’s stator has the added benefit of inherent cooling from the cold seawater.  In addition, the thin profile of the slotless stator architecture provides less fluid resistance than more traditional actuators.  Mechanically speaking, the ring architecture allows propulsion to be directly outside of the rotor (propeller), or inside (impeller). High motor efficiency, low-noise underwater thrusters are ideal for the fast growing ROV, UUV, and AUV market segments.

With more than two decades of experience in the design and production of slotless motor kits, ThinGap leverages its proven designs to deliver engineered solutions to support both commercial and defense applications underwater. With standard products ranging in size from 25 mm to 393 mm in outer diameter, ThinGap’s highly scalable motor technology can be modified to fit any environmental requirement.

How A Flight-Qualified Watch Helped Save Apollo 13

Fourteen seconds. That is the amount of time that the crew of Apollo 13 was instructed by NASA’s Mission Control to fire their Lunar Lander’s descent engine to return their damaged spacecraft back to Earth. With the ailing spacecraft being 60-80 miles off-course, this was the critical “push” that the crew needed to correct their return trajectory. The inside of the command module was close to freezing due to most onboard systems being shut down to conserve energy, including the onboard digital timer. With the odds stacked against the crew, it was up to a mechanical backup to time the engine burn – – Astronaut Jack Swigert’s Omega Speedmaster wristwatch. While the availability of a backup seems so obvious as to be an afterthought, it was in fact a decision that had been qualified by NASA five years earlier.

Flight qualification is a process by which components intended for space are subjected to a variety of conditions intended to replicate the harsh environment outside the atmosphere, not limited to vacuum, temperature, and shock. These tests are designed to push systems to their very limits to ensure functionality, an achievement that ThinGap motors have accomplished in support of an upcoming NASA mission.  Qualifying anything for use in space, whether it be a ThinGap brushless DC motor or a commercially made Omega wristwatch, is an important and complex process.

The story of the watch that saved Apollo 13 began nearly a decade earlier, with Mercury-Atlas 8 in October 1962. In the early days of manned spaceflight, astronauts were not issued watches, and instead were permitted to wear their personal timepieces. For Mercury-Atlas 8, test pilot and astronaut Wally Schirra wore his Omega Speedmaster, beginning what became a long relationship between Omega Watches and NASA.

With America’s lofty goal of fulfilling recently assassinated President John F. Kennedy’s dream of landing a man on the Moon by the end of the 1960s, no detail was overlooked, including the astronauts’ watches. By the time NASA was ready to select a watch for the Apollo program in 1965, they issued a solicitation to a handful of watchmakers based off of astronaut feedback, with ultimately only three makers responding: Omega, Rolex, and Longines.

With the three brand of watches procured for evaluation, it came time to test them in the most scientific way possible… to destruction, with the following flight certification regiment having been pulled from historical documents:

      1. High Temperature– 48 hours at a temperature of 160°F (71°C) followed by 30 minutes at 200°F (93°C). For the high temperature tests, atmospheric pressure shall be 5.5 psi (0.35 atm) and the relative humidity shall not exceed 15%.
      2. Low Temperature –Four hours at a temperature of 0°F (-18° C)
      3. Temperature Pressure Chamber – pressure maximum of 1.47 x 10exp-5 psi (10exp-6 atm) with temperature raised to 160°F (71°C). The temperature shall then be lowered to 0°F (-18°C) in 45 minutes and raised again to 160°F in 45 minutes. Fifteen more such cycles shall be completed.
      4. Relative Humidity –A total time of 240 hours at temperatures varying between 68°F and 160°F (20°C and 71°C, respectively) in a relative humidity of at least 95%. The steam used shall have a pH value between 6.5 and 7.5.
      5. Pure Oxygen Atmosphere –The test item shall be placed in an atmosphere of 100% oxygen at a pressure of 5.5 psi (0.35 atm) for 48 hours. Performance outside of specification tolerance, visible burning, creation of toxic gases, obnoxious odors, or deterioration of seals or lubricants shall constitute a failure. The ambient temperature shall be maintained at 160°F (71°C).
      6. Shock –Six shocks of 40g each, in six different directions, with each shock lasting 11 milliseconds.
      7. Acceleration –The test item shall be accelerated linearly from 1g to 7.25g within 333 seconds, along an axis parallel to the longitudinal spacecraft axis.
      8. Decompression –90 minutes in a vacuum of 1.47 x 10E-5 psi (10 E-6 atm) at a temperature of 160° F (71° C), and 30 minutes at a 200° F (93°C).
      9. High Pressure –The test item shall be subjected to a pressure of 23.5 psi (1.6 atm) for a minimum period of one hour.
      10. Vibration –Three cycles of 30 minutes (lateral, horizontal, vertical, the frequency varying from 5 to 2000 cps and back to 5 cps in 15 minutes. Average acceleration per impulse must be at least 8.8g.
      11. Acoustic Noise –130dB over a frequency range from 40 to 10,000 HZ, for a duration of 30 minutes.

As if the torturous and destructive test routine wasn’t enough, the watches were subsequently required to retain their accuracy within 5 seconds a day. The Speedmaster was the winner by default, with the Longines and Rolex having failed at the beginning of the first temperature test. Despite being the victor, the Speedmaster was still worse for wear, with all the luminous paint on the dial having crumbled off, yet its workings remained accurate to within an impressive 4 seconds a day.

The Omega Speedmaster has changed very little cosmetically since it’s 1957 introduction

The reasons for the Omega Speedmaster’s durability ultimately comes down to a simple, yet robust mechanical movement inside, as well as a rugged, yet elegant case that envelops it. Introduced in the late 1950s for use in motorsports, the Omega Speedmaster is a hand-wound chronograph (a watch with an integrated stopwatch function) with a minimalist black dial with white markings and protected by a domed bubble acrylic watch glass. The Speedmaster had become a favorite amongst pilots due to the highly reliability, legibility, and most importantly, the accuracy it possessed.

Ed White on a spacewalk during Gemini 4

With the Speedmaster now qualified for all manned space missions and extravehicular activities, they became standard issue to NASA’s crews.  In June 1965, Ed White wore his on the first American spacewalk during Gemini 4. When Apollo 11 landed on the Moon in July 1969, mission commander Neil Armstrong left his in the Lunar Lander to serve as a backup timer as the Lander’s internal electronic timer had malfunctioned. However, Buzz Aldrin chose to affix his for the moonwalk, making the Speedmaster the first watch worn on the Moon.

Buzz Aldrin in the Lunar Module ahead of lunar landing

Despite its previous widescale acceptance by the aeronautical community, the Speedmaster’s defining moment came during Apollo 13 in April 1970, after an exploded oxygen tank crippled the Apollo Lunar Module en-route to the Moon. With their vehicle critically damaged, making their lunar mission impossible, the astronauts agreed to forsake all creature comfort, and powered down all support systems, except for basic life support, including the digital mission timer to save power. Jack Swigert’s manual 14 second burn, timed on the watch, ensured that their freezing capsule re-entered the at the right angle, instead of their trajectory which would have bounced them off the Earth’s upper atmosphere and back into space.

Astronaut Jack Swigert during spacesuit fitment

The Speedmaster flew with NASA for the rest of the Apollo moon missions, and subsequent NASA programs. When Apollo-Soyuz, the first international space flight, flew in 1976, both the American astronauts and Soviet cosmonauts were seen wearing Speedmasters–an interesting detail given that cosmonauts had previously worn exclusively Soviet-made watches as a way to promote their domestic industry and were regularly worn aboard the Mir Space Station.

The Speedmaster was re-certified by NASA in 1978 for the Space Shuttle program, yet again undergoing the same rigorous regime. Through the Shuttle program, the Speedmaster remained standard issue for all astronauts, and in the 1990s, NASA and Omega collaborated on a clean-sheet watch, designed with the needs of modern astronauts in mind. This joint venture resulted in the Speedmaster X-33, which saw the purely mechanical watch upgraded to a modern, battery-powered computerized watch. Despite being superseded by a modern replacement, the original Speedmaster has still been seen worn aboard the International Space Station.

German Astronaut Alexander Gerst is seen wearing his Speedmaster X-33 aboard the International Space Station

To this very day, one can walk into a jeweler and buy a watch that is cosmetically and functionally identical to what has been flown since 1962. In fact, from the mid-1960s onward, the caseback of every Omega Speedmaster Professional (affectionately referred to as the Moonwatch) bears the inscription “Flight-Qualified By NASA In 1965 For All Manned Space Missions-The First Watch Worn On The Moon”.

1970s Omega print ads detailing the Speedmaster’s involvement with NASA and the Apollo program

ThinGap has supplied flight-qualified motors to NASA in support of their upcoming PACE mission. Focused on monitoring the overall health of worldwide oceans and atmosphere by monitoring the color of the seawater, PACE is set to launch in February 2024 from Kennedy Space Center. ThinGap is honored to support this mission by supplying custom LS Series slotless motors that drive the satellite’s primary sensor, the Ocean Color Instrument. Additionally, ThinGap has supplied more than 2,500 motor kits in support of a major commercial constellation.

Works Cited:

OMEGA and Apollo 13 – The 14 critical seconds between success and failure

NASA Testing Regime for the Omega Speedmaster Moonwatch

Apollo 13 — A Life-Saving Fourteen-Second Burn Timed With The Omega Speedmaster Professional

A Watch Made for Space but Ready for Anything

Actual Pictures Actually Showing The Speedmaster Professional Actually Being Used For EVA, Today (Well, In 2014)

Watches used in space exploration

H-LSI 267-32 Demos ThinGap’s Motor Assembly Capabilities

Designed around a low profile cogless motor with an optical encoder, precision bearing set, and anodized aluminum housing, the unit is for use in a ground-based NASA optical platform.

ThinGap recently shipped a housed version of its LSI 267-32 motor kit to a commercial customer in support of a ground-based NASA application, adding to the list of successful deliveries of housed units. Built around the company’s slotless 267 mm outer diameter BLDC motor kit, the H-LSI 267-32 integrates the high performance motor with a precision bearing set, and an optical encoder into a lightweight, Chem Film coated aluminum housing.

As a turnkey solution designed for a ground-based optical platform, this unit adds to ThinGap’s repertoire of housed and framed motor assemblies. The assembly measures 282 mm in diameter, with an axial height of 86 mm, and an internal aperture of 190 mm; the whole assembly weighs in at 8.34 kg (18.4 Lbs.), and produces a continuous torque output of 12.5 N-m, with a peak 1-second torque of 184 N-m.

Customers often come to ThinGap in need of a motor kit, wanting to take advantage of the low-profile, lightweight, and frameless architecture that is ideal for deep system integration. Yet, the time and cost of developing a housed solution are not lost on program managers and developers, so the availability of a ThinGap-led, fully engineered direct drive assembly provides a tangible advantage.

Beyond zero cogging, ThinGap’s air core motor kits have near zero Eddy current, and a harmonic distortion of less than 1%, so torque output is directly proportional to current. The resulting smooth motion and linear output makes them perfect for use in precision applications. ThinGap’s LS Series of slotless motor kits range in size from 25 to 267 mm in diameter, torque from 0.1 to 12 N-m continuous, and voltages from 24-400 volts.

For additional information on custom motor development, please contact the company at [email protected] or visit www.thingap.com.

ThinGap Releases Space Qualification Capabilities Statement

As part of regular documentation updates, ThinGap recently outlined the process by which commercial-off-the-shelf motor kits are modified for space applications. Titled “ThinGap Space Qualification Capabilities Statement,” and available on the Compliance Information page, this one-page document provides an overview on how the company handles modifications to meet the needs of both LEO applications typical of NewSpace, as well as more rigorous Government space programs, including NASA and defense applications.

ThinGap’s brushless DC electric motor kits are high quality, high performance motion components. The company has an extensive space heritage with commercial, scientific and military programs, including 2,500 motor kits supplied for an undisclosed LEO satellite constellation, 20+ space-grade programs actively being supported, and delivery of flight-grade kits for NASA’s PACE Program.

ThinGap has a standard approach and delivery set for providing space-grade motors, as well as the capability to support more stringent customer-specific flow downs, in addition to offering the space-rated off-the-shelf TGR Series.

Commercial Space Standard

ThinGap has established a commercial standard to provide “space-grade” motor kits using a set of process and material callouts. Essentially any of ThinGap’s standard motor kits can be upgraded to a space standard. The defined space upgrades provide an affordable option, especially for high volume and rapid reaction programs, such as commercial LEO applications.

The baseline for commercial space motor kits includes the following:

  • A controlled Materials and Processes (M&P) list
  • Use of low outgassing materials, per NASA guidelines
  • Class 3 PCBs
  • Leaded solder and IPC J-STD workmanship
  • Raw material certifications
  • First Article Inspection Reports

Additional Supplemental Deliverables

ThinGap can quote a wide range of customer requested flow downs applicable to motor deliveries. When requested, the company can engage third parties to satisfy requirements outside its on-site capabilities, including certain types of testing and analysis. Optional customer requested deliverables include i.) Structural and finite element analyses, ii.) On-site source inspection, iii.) Thermal vacuum testing conducted by a third party.

At the time of quoting, ThinGap requests a customer-provided compliance matrix with any required callouts or flow downs to be completed and returned by ThinGap.

Summary

The company prides itself on its heritage and being able to support a range of requirements called for by space applications.  Default deliverables are the baseline of the company’s capabilities, and can be supplemented with additional customer-specific requirements as required.

To view and download the statement, click here.

 

ThinGap Welcomes Visitors From NASA Goddard

 

Left to Right-Joseph Kay, PhD-Director of Engineering, John Baumann, President of ThinGap, and Robby Estep and Dustyn Strosnider from NASA Goddard Spaceflight Center

This past week, ThinGap hosted visitors from NASA who delivered their appreciation for the support of their PACE mission. The team from NASA Goddard gave a progress update on the mission, as well providing a Certificate of Appreciation that the ThinGap team can proudly display. NASA’s PACE mission is focused on monitoring the overall health of worldwide oceans by monitoring the color of the water, as well as atmospheric observation.  ThinGap is honored to support this mission by supplying custom LS Series slotless motors that drive the satellite’s primary sensor, the Ocean Color Instrument. NASA’s PACE Spacecraft is schedule to launch from the Kennedy Space Center in January 2024.

Renewable Energy Innovations, Generated by ThinGap

With the growing urgency for sustainable energy, pioneers are innovating new ways to harness the power of ocean waves.  Southern California based Ocean Motion Technologies is one of those pioneers. The company is developing a zero-emission energy solution using ThinGap’s motor technology in its generator mode.

Ocean Motion’s R&D is focused on sustainable, scalable, and more efficient marine hydrokinetic energy by focusing on small-scale applications like scientific & maritime buoys and moorings, offshore aquaculture, and coastal security and defense. Up until now, oceanic buoys have been powered by solar panels, which have a high cost of maintenance. Ocean wave energy is a natural choice for these use cases, but most wave energy devices are not designed for small-scale applications, as they can only function within a narrow range of sea states.

Leveraging SBIR Grants from the U.S. Department of Energy and National Science Foundation, Ocean Motion Tech has designed a wave generating prototype leveraging ThinGap’s TGD-108 (image). Originally designed and optimized for an aerospace application, the TGD-108 is available as a framed assembly with 1.4 kW of continuous power output while weighing only 670 grams or just less than 1.5 lbs.

With the adage that good motors make good generators, ThinGap’s technology is a logical choice for renewable energy applications that require overall system efficiencies. ThinGap’s unique scalable motor architecture and design offer efficiency up to 95%, and largely eliminates internal magnetic losses. The low impedance stator typical in ThinGap designs provides a stable, pure 3-phase sinusoidal, low-droop, with less than 1% harmonic distortion voltage output of clean, conditioned power.

Ocean Motion’s solution for powering data buoys is an adaptive wave energy device, with the ability to scale the technology up, and networking them together for oceanographic monitoring. The primary reason for pursuing marine power generation is due to the inherent energy density of ocean waves, which concentrates solar and wind energy and thus offering far greater energy potential in comparison.

With more than two decades of experience in the design and production of slotless motor kits, ThinGap salutes the novel efforts of customers like Ocean Motion Tech.  Ongoing and future projects designed to combine proven technology in an applied fashion are at the heart of innovative solutions like the ones being actively demonstrated in the Pacific Ocean.

Tall Motors: Scalable, Cogless Power In Action

With a focus on providing engineered solutions for a variety of high performance applications, ThinGap regularly provides modified versions of its off-the-shelf motor kits to meet customer specifications. Many of these changes include switching a motor’s winding configuration, space rating, high-temperature capability, or custom mounting configurations to create a modified-off-the-shelf product. In some cases, customers request an increase in axial height of an existing motor to improve the torque output of the motor kit without increasing the width.

A graphic showcasing two ThinGap LSI 39 variants, the original 39-10 and taller 39-39, with a caption that reads "Tall Tales," a play on words because this blog is about why ThinGap offers different axial heights, ergo a tale about taller motors, which is a double-entendre on the phrase "tall tales" which is a phrase meaning a lie.

Important to note that with ThinGap’s proprietary slotless motor architecture, torque increases exponentially with the outer diameter, but only proportionally with axial height. So while a larger outer diameter motor is always the better choice, customers often have mechanical constraints that limit their ability to accept a wider motor, making a taller product the next best solution.

ThinGap’s tooling is vertically modular, making it simpler and less expensive to change the axial height of a kit to improve torque output. Tall variants share much of the same material components with their smaller cousins, and can in many case be built in parallel. Many of ThinGap’s tall motor variants began as modified-custom solutions, such as the LSI 39-39, LSI 75-30, LSI 130-40, LSI 152-55, and LSI 267-58. By way of example, several motors sizes offer three different axial highest, such as the LSI 25 that is available in axial heights of 10, 16 and 25mm.

With two decades of experience in the design and production of slotless motor kits, ThinGap leverages its proven designs and analytical modeling that results in highly accurate transitions from predicted performance to real world operation. Furthermore, the process steps needed to produce motors of all sizes are highly scalable and ThinGap has standard products as small as 25mm, up to 393mm in outer diameter.

For a complete listing of our standard products, including our tall variants, please click here.

Zero-Cogging Motors for Precision Industrial Applications

ThinGap’s permanent magnet motors are widely used in airborne and space platforms, but there are more applications that benefit from their zero-cogging technology. With the insatiable demand for high tech devices, comes an equally high demand for precision equipment used to make integrated circuits. Today’s semiconductor equipment and test platforms need high degrees of force density, and decisive move-and-hold steps. Robust, yet compact semiconductor equipment enable inline process functions, yield enhancements, and higher levels of throughput.

Motors and actuators used in wafer processing and test require the benefits of cogless, absolute precision. Low profile motors are ideal because of the large internal aperture so that optics, cabling, or prisms can be routed through the center, yet be compact, enabling deep system integration. Additionally, precision brushless motors are used extensively in optical systems for applications such as beam steering, delivering micron-level resolution.

The ongoing transition to direct-drive solutions enables system-level advancements needed by today’s semiconductor industry. Frameless, slotless motor kits with high torque are in many cases the ideal solution for semiconductor equipment with low profile, high torque coreless motors being the right fit for metrology and optical-based systems.

Beyond zero cogging, ThinGap’s air core motor kits have near zero Eddy-current, and a harmonic distortion of less than 1%, so torque output is directly proportional to current. The resulting smooth motion, linear output makes them perfect for use in precision industrial applications.

ThinGap’s LS Series of slotless motor kits are an industry leader for semiconductor applications. Standard kits range in size from 25-267 mm outer diameter, and a continuous torque output from 0.1- 24.4 N-m. Always cogless, always low profile and with high power density and with standard and modified configurations, the LS Series is ideal for semiconductor applications.

ThinGap Renews ISO 9001:2015 Certification Until 2026

Renewal for three more years underlines ThinGap’s commitment to stringent customer quality requirements and the widely recognized ISO Standards

ThinGap’s ISO 9001:2015 certification has been renewed for another three years, and will remain in effect until March 2026. An audit and renewal of ThinGap’s certificate was completed by American Global Standards, LLC of Montecito, CA as the basis for the Certification renewal.

An image of ThinGap's updated ISO 9001:2015 Certificate, issued March 28, 2023

Based on ISO 9001:2015, ThinGap’s Quality Management System (QMS) serves as the baseline for delivering high quality products to many customers with program-specific QC requirements for a wide variety of industries. ThinGap has a track record of supporting the exacting requirements for its base of Fortune 500 companies, Government customers, including NASA, and regulatory specifications across multiple sectors, be it space, medical, defense or airborne.

With more than two decades of experience in the design and production of slotless motor kits, ThinGap can leverage proven designs and analytical modeling that results in highly accurate transitions from predicted performance to real world operation. Furthermore, the process steps needed to produce motors of all sizes is highly scalable; ThinGap has shipped motors from 19 mm up to 600 mm in size.

ThinGap Demonstrates High Power Motor Capability with 100 kW Motor Kit

Showcasing ThinGap’s highly scalable slotless motor technology, the TGO 385 was designed with renewable energy in mind, but many potential applications exist.

ThinGap has completed its latest large-size motor prototype, the TGO 385 for a commercial customer. The TGO 385 motor kit has an outer diameter (OD) of 385 mm (15 in.), and an axial height of 223 mm (9 in.), making it about the same volume as a 5-gallon bucket.  The power output capability of the TGO 385 is estimated to be 100 kW or more depending on the application.

Showcasing the highly scalable nature of ThinGap’s motor architecture, the TGO 385 is the newest variant of the TG Series of slotless motor kits. The company’s TG motors are unique in having a stator architecture with an ironless coil. Due to the absence of slots or “teeth”, ThinGap’s stators do not saturate during operation, allowing the motor kit to produce more torque as current is applied, without the falloff seen in traditional iron core motors. Combined with a mechanical design that promotes convective cooling during operation means that the TG Series has unrivaled power density.

The TG Series has been successfully used in a wide variety of generator, propulsion, and flywheel applications, ranging from gyro-stabilization in boats and satellites to airborne starter-generators. To learn more the highly efficient, zero-cogging TG Series of slotless motor kits, click here.

The TGO 385 demonstrates ThinGap’s ability to deliver tailor-made high-power solutions.  With more than two decades of experience in the design and production of slotless motor kits, ThinGap leverages its proven designs and analytical modeling that results in highly accurate transitions from predicted performance to real world operation. Furthermore, the process steps needed to produce motors of all sizes is highly scalable, and ThinGap has shipped large class motors of up to 600 mm OD, ranging from 10-400 kW of output power.