It may be tempting to assume that a drive is just a drive, but you’d be sadly mistaken. As more than 100,000 Danfoss drives worldwide are providing effortless speed control and optimized efficiency for even the smallest chain hoists to the largest mobile crane vessels with lifting capacities up to 1,000 tons, we dare argue that drives are in fact not just drives. Quite the contrary, specialized drives for cranes are a large part of the Danfoss Drives repertoire and a vast number of features make them worth considering for your crane application – no matter what your needs are. We’ve highlighted five in this blogpost.
Broad power and voltage range to meet your needs
One of the deciding factors when opting for a drive supplier is the power and voltage range to ensure the right solution regardless of your needs. Depending on your business or application, you may require either a low or a high voltage range and power. Either way, you want the best solution without having to settle for less, right? That’s why you can opt for both VACON® and VLT® drives for your crane application. Across the entire Danfoss drives product range, we offer drives from 230 V up to 690 V and from 250 W up to 5,3 MW, ensuring you can get a solution fit for your needs.
Optimum enclosure type for your application
AC drives can survive for years and years in sometimes very harsh environments and one of the reasons why this is possible is of course the quality of the drive, but the enclosure of the drive also plays a vital role in keeping the drive alive long-term. Danfoss Drives offers different enclosure types ranging from IP00 for installation in panels up to IP66 for outdoor installations. (For a deeper understanding and elaboration of the IP ratings and enclosure types, please see this blog post on the particular subject). That way, you will get the optimal and exact enclosure type required for your application irrespective of the environment in which the drive will be located.
Considering the environment for your drive from the beginning could be worth your while as the right enclosure can result in a combination of reduced maintenance costs, lower service costs, an increased operational reliability and finally more uptime. An additional, but not so insignificant aspect of enclosure types is the issue of space. Choosing the right type could for instance allow you to place the drive outside and thus save the whole panel and reduce shop floor space consumption to a minimum.
The optimum enclosure type clearly depends on the environment the drive will operate in. A crane situated in a desert will need to endure a constant blowing of sand and dust. On the other end of the scale, but equally in need of protection, we have harbor cranes or cranes at sea that work in very wet climates. In both cases, opting for IP55 would be ideal. Another scenario could be cranes operating in either very high or very low temperatures thus facing different challenges for which they need the proper protection. So, the right enclosure type really is important to ensure your equipment operates optimally its entire product life.
To sum up, having the freedom to choose the ideal enclosure type for your installation gives you flexibility in the construction of your system. For instance, you can choose a lower IP rating, e.g. the IP21 for an indoor drive installation without the panel and save money as the need for protection is low. Or you could go for IP66 for an outdoor installation outside of the panel – needing more protection, but reducing space consumption, eliminating the cost for air condition and reducing total cost of ownership. So, the different protection classes really are a tool for optimizing your installation.
Motor and system independence for utmost flexibility
A drive’s first job is to control a motor and run it in the most efficient and optimal way to save energy and prolong the lifetime of the motor and the connected components. This is what we’ve been refining for the past 50 years of manufacturing AC drives. We know drives, but we’re leaving the choice of motor and control system completely up to you. Our drives are compatible with whatever you choose so you can have the components that suit your application best. We like to think of this as an alternative to a system package approach, where you are in charge of your system.
Flexibility in your system also means you can connect many different control systems to our drives and choose between a broad range of fieldbus interfaces. As a result, you never have to compromise on the best equipment for your needs. Due to innovative drive technology, we can ensure you that a Danfoss drive motor control always delivers the optimum efficiency, independent of the connected motor supplier. The drive simply adapts to the motor and finds the best operation point.
This is ideal for both OEMs and end-users as you are completely independent when selecting the best-fitting components as opposed to a predefined package deal. You may also, at some point, need a spare part which can be tricky to locate as the years go by if you are bound by a certain system package.
Achieve the ultimate flexibility with hybridization
Using a combination of diesel and battery-stored electrical energy creates opportunities to control the generator speed and reduce fuel consumption by up to 50%. The battery storage will cover short-time peak loads and the diesel generator speed can be adjusted to the actual power requirement.
A hybrid solution lets you shift power consumption from the grid to off-peak periods. By charging batteries at night-time off-peak rates, then using the stored power as the demand arises during the working day, crane operators can use time-shifting to reduce electricity costs for daily operations.
You will also be able to shave peak loads by using battery-stored power to boost peak load demands, for example when high torque is required at the start of a lifting operation, the electric motors are shielded from the peak load demands. Ultimately, this means the crane manufacturer can dimension the motors to the regular load, rather than to the peak load.
Finally, you can use battery back-up to replace spinning reserve that might be otherwise achieved by running diesel generators. As batteries become cheaper, the viability of integrating batteries in cranes for back-up in the event of power supply failure, increases.
Unique back-channel cooling will slash your energy bill
There is no denying the need for air conditioning in a crane switch room. You typically have very few square meters as well as several drives and other equipment emitting heat creating an inevitable need for air conditioning. What other choice do you have? The equipment stored in the switch room will eventually fail and break down due to the heat. So, you pay. That is if you don’t have AC drives with back-channel cooling. The VLT® AutomationDrive FC 302 with the unique back-channel cooling feature gets rid of as much as 85% of the heat coming from the drives saving a considerable amount of money otherwise needed for air conditioning. This makes your equipment last much longer, reduces the total cost of ownership, minimizes the size of your air-conditioning system in an already crowded room and leaves a smaller footprint due to internal cooling capabilities.
Which drive to choose for which purpose?
Hopefully, we’ve provided some compelling reasons to consider an AC drive for your crane application, but which one will bring you the most value? We’ve compiled a small guide below for you to determine which AC drive will suit your exact needs best.
If you’re a system integrator, machine builder or an OEM who wants to design and build efficient industrial drives systems, the VACON® NXP Common DC Bus is for you. The NXP Common Bus components are used in a multitude of combinations across a wide spectrum of high-power process industries from the pulp and paper, steel, metal and mining, and marine cranes to smaller machines and productions lines which also demand cost-effective solutions, thus making the VACON® NXP a very versatile choice.
If higher power sizes and system drives for demanding industrial applications are what you’re looking for, the VACON® NXP Air-Cooled is what you need. The entire NXP series offers outstanding technology features such as anti-sway functionality, which can improve your productivity by 15% (don’t miss out on our blogpost covering this topic.).
The VLT® AutomationDrive is a robust, built-to-last AC drive operating effectively and reliably even with the most demanding applications and in the most challenging environments. A wide operating temperature range of -25°C to +50°C without derating ensures reliable operation when your applications take your drive to the extremes. The flexibility of available enclosure types is yet another differentiating factor, ranging from IP00 all the way up to IP66. Its cutting-edge thermal design and unique back-channel cooling make VLT® AutomationDrive one of the most compact and cost-efficient drives in the market.
If, on the other hand, you want something smaller while keeping precise and efficient motor control for cranes and hoists, the VLT® Midi Drive FC280 is ideal. The right mix of features ensures that the VLT® Midi Drive is ideal for OEMs, system integrators and machine builders, and it complements a wide range of crane and hoist applications.
Where air quality is critical, space is limited, and efficient heat transfer is required, we’d recommend the VACON® NXP Liquid-Cooled. No need for air ducts or large fans, combined with a compact size, means you achieve a high-power density in your installation – and virtually silent operation. You save on both investment and operating costs when removing heat using the liquid medium. With robust operation even in demanding conditions and with only minimal air filtering in dusty conditions, you achieve maximum uptime.
If your drive needs vary from the ones outlined above, please get in touch with your local Danfoss Drives Sales office to learn more about a solution fit for your exact purpose.
Finally, to prolong the life of your AC drives, Danfoss Drives offers the DrivePro® Life Cycle services that cover the full lifetime of the drive making the most of your crane application.
Author: Michael Müller, Global Vertical Development Director, Cranes/ Hoists/Lifts