One miracle too few: Andretti and HMI part ways

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It was one of the big stories of pre-season testing, the sight of the Andretti Formula E car stuck in the garage and repeatedly stopping on track. What was happening behind the scenes for the months leading up to season 2, was a development effort that was severely rushed and held up due to funding issues.

The company behind the eMotor and inverter was NASA spin-off Houston Mechatronics, Inc. Despite real potential in the project, in early 2016 Andretti “suspended” ties with the company. e-racing.net managed to speak exclusively with Houston Mechatronics CTO and co-founder Nicolaus Radford about the project and where it seemed to go wrong.

Houston Mechatronics, Inc (HMI) was formed out of a group of ex-NASA roboticists. During Radford’s time at NASA, he and his team were often forced to design custom motors, delivering high torque and power density. Through this, he specialised in the development of ‘variable flux’ motors, and he believes this revolutionary work was initially what caught the eye of Andretti, although it was decided that extremely promising technology would take a back seat for a more traditional approach at first.

[pullquote align=”right” cite=”” link=”” color=”” class=”” size=””]“We were probably the only people to design the motor and inverter from a blank piece of paper”[/pullquote]

Despite being a young company, HMI realised the potential significance of this Formula E project, and the “company fronted some of the costs” for the joint Andretti-HMI powertrain. The company swiftly started with the electromagnetics of the motor, as well as designing an inverter, all completely from scratch , while others such as NEXTEV and DS took off the shelf parts from established motor manufacturers like GKN and YASA respectively. Abt Schaeffler Audi Sport seems to be the only other team to have taken a ‘ground zero’ approach to their design.

With their designs in hand, HMI and Andretti had to find a manufacturer to assemble their ambitious motor. However, this is where the project got caught up. Radford claims that despite hiring “great guys like Roger Griffiths”, Andretti simply didn’t have the secured sponsorship to get an experienced motor manufacturer to produce their design. Instead they had to go for a smaller, less experienced outfit that proposed to build it for free. This manufacturer struggled and as Radford puts it, “they were a little out of their comfort zone and ended up with some berthing pains on the first prototype motor and ultimately had to rebuild it. This took the wind out of our sails.”

With their limited resources, this meant the schedule slipped by a critical two months, as the manufacturer had to make a second effort at constructing the motor. Once it had been built there was not sufficient time to run the powertrain on the dyno and tweak any elements accordingly as originally planned. “We obviously didn’t intend to have the first prototype going straight into the car” says Radford, but this is exactly what happened and the reason why testing at the track was so difficult.

“Honestly, the real development money came too late” and Radford believes that if the sponsorship from TE Connectivity and Amlin had landed sooner, it very well could have been a different story. Despite this, Radford was clear that he didn’t want to slag-off Andretti as they “were committed as much as they could be and fought to the very end”, giving credit to their determination and will power.

Radford says he’s “frustrated” at what Formula E’s roadmap was, because it turned things into an “integration effort” by teams as opposed to actual innovation and development, which is what he believed the series intended. People like HMI suffered despite their electromagnetic design being “world class”. “We were so f***ing close! We needed 50 miracles and we got 49 of them.” Radford says it was impressive that they got as far as they did with the modest resources available.

In hindsight he is convinced that “had we to do it over again, we should’ve developed the motor for season 3 but ran the McLaren motor and developed our own inverter for season 2. Our inverter was revolutionary in its own right, and had no significant issues. We just tried to tackle both with way too limited resources.”

There is no doubt that Radford and his team from HMI have great respect for the Andretti engineers and praised all involved. They are glad they got into Formula E, and through it they designed an exceptional motor and inverter. HMI are now approaching other teams who are looking for electronics partners. When asked about a potential Dragon Racing link up, Radford says “if Dragon are looking for world-class motor performance, they should ask us.”

One of HMI’s innovations used in their Andretti inverter, was state of the art Silicon Carbide switches, which turn the DC power of the battery into the 3-phase AC used by the motor. Radford claims these are up to “50% more thermal efficient” than traditional IGBTs used in current day inverters. The truly exciting innovation for electric cars that HMI is working on is variable flux memory motors, also called online real-time flux controllable motors. This technology didn’t make it into the ATEC-01 but has huge potential.

What makes them unique is that the magnetisation strength of the magnets in the rotor can be changed by using short pulses of current in the stator. This acts as a transmission buried right inside the motor. HMI have already built two working generations and are in process of building a third. “Imagine ensuring you are always operating the motor at its most efficient point. And not only that, this type of motor has an exceptionally wide and efficient speed envelope, completely changing the way people think of designing transmissions with electric cars. I love this stuff! It’s such an exciting time.”

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Images courtesy of Houston Mechatronics, FIA Formula E Media and Amlin Andretti Formula E

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