Next-generation electric winches are rapidly being adopted on marine vessels, replacing the older hydraulic and early electric units. Imagine electric anchor/mooring winches with no hydraulics, motor encoders, gearbox load cell sensors or external controllers. ABB has them today, certified for marine use and speaking deck machinery language.

Deck machinery winches for anchoring and mooring are fundamental equipment on all marine vessels, with hydraulic-oil-driven winches traditionally being used. Winching operations are very challenging since a slack mooring or anchor line with almost zero tension at the start has to, in just a few seconds, deal with torque rapidly racing to extreme levels. To properly maneuver and secure high-mass marine vessels moving on the water surface, it is vital to have precise and 100% reliable control of the huge torque forces at work.

Hydraulic oil still dominant, until now

Electrical three-speed winch motors with contactors have existed already for many years, as have electrical VSD (variable speed drive) solutions with basic functionality. Although these first-generation electrically-driven winches offered improved control and positive environmental benefits, they were not widely accepted. The DOL (Direct on Line) motors with 3 motor windings for low-middle-high speeds had limited success, as did the early VSD design which included a PLC with winch application, motors with encoders and tension control via load sensors.

Drawbacks of this first generation included costly motors with three windings, a high starting current, high noise, and the requirement for electrical cabinets with contactors for each set of windings in the motor. In addition, external control via old control cards raised questions about support, maintenance and spare parts. On the early VSD winches, external PLCs, encoders and load sensors made the systems complicated and sometimes unreliable.

The result, until recently, has been that older hydraulic systems have so far been maintained by approximately 70% of the worldwide marine vessels. This is understandable considering the fact that winch builders, and of course shipowners, are extremely careful with their multimillion dollar vessels and cargoes. This clearly is not a place where new things are tested before they are first well-proven with years of experience on both the hardware and software. To create a smart, secure, drives-based solution for deck machinery, ABB decided to take a different approach.

Smart, fully-integrated electric winch control

“To successfully break into the electrically-driven winch sector, and displace the older hydraulic technology, we realized we needed to offer more than basic products like drives and motors,” explains Mikael Holmberg, ABB’s market manager for marine winches. “To really gain the confidence of the deck machinery builders and shipowners, deep application experience and expertise was required.”

To win that confidence, ABB has been developing a new integrated drive-motor-control approach for anchoring, mooring and other deck winches since 2007. Working side-by-side with many of the biggest winch manufacturers on the deck machinery market, ABB gained considerable insight into ways to use its own world-leading expertise in drives and motor control. The result has been a new winch concept, much different from the previous electrical attempts. Based on ABB’s direct torque control (DTC) platform, precise motor control and operation is achieved without any encoder or load cells, at full torque, over the whole speed range.

Marine certified, speaking marine language

“On top of the motor control, we created a specific winch control application in cooperation with the leading OEMs. So we studied real market requirements and implemented them in the drive, tailoring both the hardware and software to maritime vessel operations, speaking a very understandable marine winch language,” continues Mikael. “In addition, ABB drives and motors have marine certification which has been critical role in gaining acceptance of new maritime machinery and technology.”

This is good news for vessel operators since the driving force to move away from hydraulic piping, namely high maintenance and environmental damage due to oil leakages, is still there. With the newest generation of electrical winch systems greatly simplifying control and clean operation, the marine market is clearly taking a second look at electrical solutions, specifically the ABB DTC platform.

Total winch control built in the drive

Clear user benefits come from all key features being built directly into the new ABB winch drive. “By putting the winch application inside the AC drive and eliminating the external devices,” continues Mikael, “we simplify the system enormously. This achieves precise VSD motor control and auto mooring/tension operations internally, without costly and troublesome encoders, load cells or external controllers. This, in a nutshell, is why we are now rapidly gaining market share from the old hydraulic methods and having more and more customer success stories with ABB electric winches.”

Of course it’s not that simple, as a lot of work and experience has been devoted to the new technology. For decades, ABB has been a world leader in AC drives and AC motors, and its deep technical expertise in frequency converters has allowed it to come up with these novel solutions. Adding assurances to the maritime market is the marine certification and the presence of ABB service people in the world’s most important harbors.

Benefits from the simplicity

The winch drives for marine and offshore environments give the following benefits to users:

• Full torque at low or zero speed, enabling winch start/stop without jerking.
• Reduced noise via stepless speed and torque control.
• Synchronized control for mechanical disc brake in starting-stopping of the winch.
• Dynamic braking with integrated brake chopper and external braking resistor.
• Control software with tailor-made parameters for anchoring, automooring and handmooring.
• Available in low harmonic and regenerative variants.

The marine drives started with ACS800 platform, followed by ABB marine motors in the offering, and now the new ACS880 platform is also tailored for winches. Moving forward, ABB will be optimizing the DC grid supply onboard ships and the direct DC supply to the AC drives.

For OEMs and retrofits

To serve this growing marine winch sector, ABB today has built two dedicated business areas, the first for Deck Machinery winches for anchoring and mooring, and the second focusing on various Offshore winches for general use on ships and rigs. These dedicated groups offer both new installations alongside OEMs, as well as retrofits of older generation electrically driven winches.

Test winch and motors before you buy

The wide scope of products that ABB offers means it can, when requested, supply complete single-source packages including motors and drives with optimized dimensioning. In Helsinki an application lab and a customer pilot plant includes an ABB deck machinery motor, mechanical drum and gearbox which means the customer can actually run the package to monitor performance. Whatever the case, every customer can test the ABB winch drive to show how it will perform on their motors, even if they decide not to use ABB motors.

“The best challenge for us is truly a customer problem,” concludes Mikael. “We see the problem actually as an “opportunity” for a new solution, and via this route we find such solutions for the application/process in each specific winch application. We are happy to hear about winching problems because we know we can find drive-based solutions. So what we show in presentations in customer meetings, we are ready to prove in actual functional performance tests.”

Robust and cost-effective electrical winching

In summary, higher levels of operational reliability and more precise regulation of lower motor speeds with high torque levels are today achievable. This is accomplished via the combination of direct torque control (DTC) with a specific but flexible winch control program. This unique ABB solution eliminates the need for motor shaft encoders and gearbox load cell sensors, while also eliminating the environmental risk posed by oil leaks.