Developer interview

Developing the World’s Fastest Elevator
[Drive Performance]

Drive and Control Technologies
to Produce the World’s Fastest Speeds

Fast-growing Asia is the scene for a stream of plans for enormous buildings. In particular, there is an ongoing rush in China and the Middle East to erect super high-rise buildings taller than 500 m. For such buildings, elevators, as “vertical transportation infrastructure,” are expected to get people to their destination floors faster, and elevator speed becomes an important factor. The development of the world’s fastest elevator has been a goal for us at Hitachi since we built the 213 m “G1TOWER” in 2010, as what was then the world’s tallest elevator research facility.
Hitachi then achieved the world’s fastest elevator for CTF Financial Centre, a 530 m multipurpose complex in Guangzhou, China. The elevators take approximately 42 sec to ascend the 440 m from the 1st floor to the 95th, a rated speed of 1,260 m/min.

Reconciling High Output with Compact Size

The first challenge we face in achieving ultra-high-speed operation is how to make the machinery smaller. Reaching higher speeds requires horsepower from the traction machine which winds the cables connected to the elevator car and counterweight. Also, when the travel range is as long as 440 m, the weight of the main rope itself that suspends the elevator car increases to a significant level, requiring more power. That requires higher capacity for the control panel which controls traction machine speeds, so the machinery keeps getting bigger. Ryo Maeda of the Mechanical Systems Development Group says “This is an elevator to go to the hotel on the observation floor, so the machine room space is limited by the tradeoff against guest room space. It was a challenge to reconcile the pursuit of higher output with the need to save space.”

Mechanical System Development Group
Elevator System Development Dept.
Development Div.
Development & Production Management Div.
Elevator & Escalator Div.
Ryo Maeda

To that end, we pursued the new development of a 347 kW permanent magnet motor—one of the world’s most powerful—while also working to make it slimmer. We succeeded in raising motor output by about 30% while also cutting 13% off the width of the traction machine. For the cables, we adopted high-strength cable with a new design of materials and filament winding method, raising strength by 30% in order to achieve a 30% weight reduction. Maeda says “Cable strength must be increased to make the cable lighter. But in general, stronger materials are stiffer and have shorter lifespans. Cables require flexibility to wind onto traction machines correctly. We worked hard to achieve the three elements of strength, lifespan, and flexibility at high levels.”

High-strength cable with newly designed materials and filament winding method

The control panel has four IGBT modules connected in parallel to achieve 2,200 kVA of output, one of the world’s most powerful, with dimensions half the size of conventional equipment. “Elevators are used for at least 20 years, so development must also consider ease of maintenance,” says Masaki Miyamae of the Control Systems Group. So, the development process also considered the ease of bringing equipment into the machine room and the ease of inspection and parts replacement. The control panel configuration is divided between individual functions, and units can be pulled out, for easy inspection and replacement. That is how we completed the drive and control equipment to produce the world’s highest speeds.

IGBT: Insulated Gate Bipolar Transistor

A traction machine produced at Mito Works. It achieves the high output needed to produce the world’s fastest speed while also being reduced in size.

Reaching 1,260 m/minute with Improved Brake Reliability

On site, the equipment was installed and constructed by the construction division of Hitachi Elevator (China) Co., Ltd., under the direction of the construction division in Japan. Miyamae says “On site, adjustment to match floor levels was a tough challenge. When the movement range is 440 m, cable elongation becomes significant, and vertical oscillation of the elevator car can easily occur, so stop positions are often off the mark. We put enormous effort into the adjustments to stop the elevator car at floor levels with high precision.”

At a speed test in May 2016, we succeeded in reaching a speed of 1,200 m/min, which was then the world record. In June 2017, after further improvements to the control and safety devices, we successfully recorded the world’s highest speed of 1,260 m/min. Maeda says “Our main target for improvements to get to 1,260 m/min was the reliability of the braking system that stops the elevator car. In ordinary elevators, the frictional heat generated by braking in an emergency doesn’t exceed 200°C, but when speed is as high as 1,260 m/min, the temperature can momentarily exceed 400°C, so we developed braking materials able to withstand that harsh environment. We also repeated tests countless times on equivalent test equipment, calculated friction levels, and created an algorithm that predicts the timing for brake replacements, which we incorporated into the control system.” Kazuyuki Takaku of the Products Quality Assurance Dept. says “When we installed the improved brakes on the traction machine, our staff from Japan and the on-site staff all had to work together to get it done according to the initial plan. Working to finish with limited time and manpower taught me the importance of a team really coming together.”

Control Systems Group
Elevator System Development Dept.
Development Div.
Development & Production Management Div.
Elevator & Escalator Div.
Masaki Miyamae

Technical Development Projects Which Set High-level Goals

Looking back on the project, Maeda says, with a smile, “1,260 m/min is a speed that can’t be tested even in the G1TOWER. It would be difficult to tackle problems that we only discovered on site, so the design plan was everything. We had to work through everything we could think of to the end. That was a heavy responsibility, which made the job that much harder, but the sense of achievement from getting it done was something special.” Takaku says “My position is to assess and test what the engineers have designed, and apply that to products. It was a joy for me to cooperate with people on site to assess the equipment that the engineers had put their all into creating, and complete the project without problems.”

Miyamae says “I see taking on the challenge of world-record speed as a rare and precious opportunity, so it was a great experience.” As he says, this project was also a place for training the young engineers who are the future of Hitachi Elevator. We expect them to absorb the attitude for setting high-level goals when undertaking technical development, and to apply it in future development work.