Connectorization Saves Money in Both Manufacturing and Maintenance

Transcription

1 WHITE PAPER People Power Partnership Connectorization Saves Money in Both Manufacturing and Maintenance Cory Jenkins and Richard Carlson HARTING of North America, Inc. Most industrial equipment, whether intended for indoor or outdoor use, contains extensive electrical wiring between its components and subsystems. When the equipment is manufactured, the machine builder typically assembles and tests most of the system at its plant prior to shipment. Then it is disassembled, including disconnecting much of the point-to-point wiring, and shipped to the customer s site. There it is reassembled, the wiring reconnected, and any remaining electrical wiring done. During installation it s common for point-to-point (hard) wiring errors to occur, which can cause equipment damage on startup, or at a minimum cause startup delays due to troubleshooting time and repairs. Troubleshooting any subsequent electrical problems as part of maintenance operations is also complicated by hard wiring. Connectorized wiring can make both equipment production and subsequent maintenance more efficient and cost effective, as a few real-world examples will demonstrate. How Connectorization Saves Money Most plant engineers are familiar with the concept of a communications bus, with drops coming off a main trunk cable; it s how Ethernet and other common networks are put together. What may be less familiar is that power for motors and control signals can be distributed the same way. In fact there are connectors available that make it possible to use a bus structure to carry both motor power and control signals, using a composite trunk cable containing both kinds of wires, and with individual power and control drops to each motor. A cable bus system is custom-designed and assembled at the factory along with the equipment on which it will be used. As the equipment is assembled the bus cable is run and drops are connected. After factory acceptance testing is done and it s time to ship to the customer, the connectors are unplugged, then plugged back in at the customer s site. Reduced Manufacturing and Debug Costs This method saves money during both the manufacturing and debugging of equipment, and when servicing in the field. During manufacturing it makes it easier to design equipment as a series of modules. It also allows the equipment to be shipped in smaller pieces, and makes planning for expansion simpler. In addition it makes it feasible to pre-build standard components like control panels, motor assemblies and power distribution boxes, which will all be plugged together at assembly time. All this leads to a better-looking, neater design, with less panel clutter. And it makes troubleshooting easier.

2 During assembly, connectorization cuts initial wiring costs by eliminating the need for conduit; cuts debugging and testing costs by using pre-wired and tested cable assemblies, and improves manufacturing efficiencies and logistics by allowing staged panel assembly. With everything connected by plugs, disassembly for shipment involves just unplugging the different parts; there is no need to separately unwire I/O, power, pneumatics and signal cables. Installation at the customer site also goes faster with connectorization. There is no need to test, rewire and troubleshoot wiring just plug everything in. This means fewer wiring errors. And because this is faster than connecting individual wiring it reduces on-site costs for personnel, travel and other expenses. All this helps make for a happier customer. Once the equipment is up and running it must be maintained, and connectorization helps here, as well. With everything in plug-and-play modules, there is much less chance of wiring errors. Equipment is more reliable, and when something does fail it can be replaced quickly. This too cuts down on personnel, travel and on-site expenses. In some cases customers may do some of their own repairs, since many components can be plugged in rather than wired in, all of which leads to lower maintenance costs. Cost Comparisons Connectorization has benefits, but at what cost? The connectors themselves cost money, and designing and assembling the cable system entails labor costs. Representative numbers based on time studies by HARTING on cable assembly operations can shed light on this. The numbers present below do not include additional costs like travel, downtime and field personnel, only direct component and assembly costs. So the cost savings presented tend to be conservative. Each machinery manufacturer will have different labor and overhead costs, but in a time study at one factory the fully burdened cost for hardwiring one pair of connection points on a complex piece of equipment was about $80. For the initial installation of connectors on each end of the same cable, experience shows there is 40% added cost for connector wiring, plus the cost of the connectors. With two connectors typically costing $60, that brings the initial connectorizaton cost to $ $80 = $172 at the manufacturer s plant. At this point, connectorization costs $92 more than hardwiring. However, the labor cost to disconnect hard wiring from major assemblies before shipping them to the field will narrow that cost differential, because simply unplugging subassemblies carries little cost. Field experience shows there is about a 30% premium on field wiring labor costs compared to the same hard wiring done in the plant. If we assume that major assemblies are shipped to the jobsite fully assembled, this means that hard-wired cables must be disconnected in the field, and then reconnected for installation. In that case, the total installation cost for a single hard-wired cable at the jobsite is $ = $208. Because the cost of unplugging and replugging two connectors on a cable is negligible, this brings a net savings from connectorization of $208 $92 = $116. Any subsequent disconnecting and reconnecting required due to field-wiring errors and troubleshooting will generate additional savings from connectorized cables. Some specific machinery examples follow.

3 Crane Application A large material handling crane had to be taken apart for shipment and re-assembled at the end customer s site. The job encountered delays, extra costs and errors during initial installation. The solution was to replace hard wiring with hybrid connectors (Figure 1), which reduced field installation time from weeks to three to four hours. Figure 1. Replacing hardwiring on a large material handling crane with hybrid connectors drastically reduced field installation time. A cost study showed that during initial assembly, labor cost with hard wiring was $6750, while with connectors it was $12,540 ($3225 for the connectors themselves plus $9315 for labor), costing an extra $5790. During initial installation in the field, the hard-wired cost was $13, for labor, versus the $12,540 with connectors, for a saving of $ with connectors. Based on past experience with wiring errors, a subsequent disconnection/reconnection of the hardwiring resulted in a similar $13, installation cost. This brought the total hard-wired installations costs up to $26,325, while with connectors it was little more than the original $12,540, saving around $13,000. Unwiring and rewiring for maintenance and repairs drives the savings even higher.

4 Press Brake The installation of press brakes for bending and forming sheet metal products frequently had problems and startup delays due to miswiring of power and signal connections to the control pedestal. Changing from hardwiring to two cable assemblies saved about an hour of wiring time in the field and, more importantly, guaranteed no errors. Here s how the costs broke down: During initial assembly, labor cost with hard wiring was $175 (2.33 hours $75/hour). Connectorized wiring costs were $ ($ for cable assembly labor plus $83.42 for the connectors), costing an extra $ During field wiring, the one hour of labor saved with connectorized cables resulted in a net savings of more than $100 compared to hard wiring. Heavy Mobile Equipment Engine Production Plant This application involved power distribution and motion control on a long conveyor and engine block production line. The two key inputs to the drive motors for the conveyor and transfer mechanisms are electrical power and control signals. The power is 480 Vac, and the control signals are 24 Vdc. The fieldbus used for drive motor control is the AS-Interface, in addition to PROFIBUS and PROFINET for other control applications. Wiring options were to hard-wire separate power and control lines to the drive motors through a single cable, wire with separate connectorized power and control cables, or make up composite cable assemblies with connectors that would accept both the AWG 10 power lines and AWG 16 signal lines. The last choice would require some sort of patch panel or hybrid connector at each drive motor location for the cable drops that run to the motors. It turned out that HARTING North America was able to supply a hybrid T connector for the cable drops to the motors (Figure 2). Figure 2. Connectorized power and control wiring with hybrid connectors, including a T for cable drops to conveyor line drive motors.

5 The conveyor was put together in modules, which were shipped to the site, put in place and plugged in, with no hard wiring. Assembly of the wiring required minimal use of tools, and could be done even without construction drawings. A cost analysis verified that this approach was most cost effective. More than 600 hybrid connectors were used on the composite cables carrying power and control signals. This allowed considerable design flexibility, the use of lower-cost off-the-shelf hardware, and reliable and easy-to-service connector designs. Wind Turbines Wind turbines require a lot of wiring, with electrical power, data communications, and control signals. Traditionally, this has been done with point-to-point wiring, often run through flexible conduit. That approach is labor-intensive at the factory, both for initial assembly and during disassembly prior to shipment to the job site. It also adds to difficulties during field installation, where it makes testing and debugging more complicated not to mention difficulties with inexperienced local contractors. Customized modular connectors are now available that combine optical fiber, Ethernet, coax, pneumatic lines, electric power, and more (Figure 3). These hybrid connectors make it possible to assemble all wiring at the factory ahead of time under controlled conditions. Cables are unplugged for shipment to the field, and then plugged in again on site, with little opportunity for error and without the costs of point-topoint wiring. Fig. 3: Example of a mixed-purpose (hybrid) connector that combines various types of signal, power and control. A cost comparison for hard wiring vs. connectorization in a wind turbine installation is very similar to the study presented in the Cost Comparison section earlier. However, wind turbine towers have so many different subassemblies that the odds of having wiring errors during installation are greatly increased. This makes connectorization all the more valuable.

6 Paper Cup Manufacturing Paper Machinery Corporation (PMC) manufactures high-speed paper cup forming and packaging equipment. A recurring problem has been delays and cost overruns on start-ups at customer locations. All of PMC s equipment is built and tested in their Wisconsin facility, then disassembled for shipment. The connections to the large enclosures holding the controls were a part of this disassembly process. At the job site the customers would hire local electricians to do the wiring, but errors were a common occurrence, resulting in budget overruns. This made it necessary for PMC to send out engineering personal to fix problems, which were costly and hurt relations with the customers. PMC then switched over to connectorized wiring (Figure 4) for switches and patch cables. This sped up onsite assembly significantly, reduced wiring errors and troubleshooting time, and saved a lot of money. Figure 4. A switch to connectorized wiring on a machine that makes paper cups saved money, sped up onsite assembly, and reduced wiring errors and troubleshooting time. Aluminum Smelting The Norwegian company Goodtech is developing an energy recovery system called TurboCron that recovers waste heat from the electrolytic cells (Figure 5) used to produce raw aluminum, and converts that energy to electricity.

7 Figure 5. The TurboCron system that recovers waste heat from electrolytic cells making aluminum uses connectorized wiring to shorten maintenance times. It is critically important that the heat recovery system not impair the aluminum production process, either while operating or during maintenance (which can cause a furnace shutdown if it takes too long). With this in mind, Goodtech paid careful attention to service-friendly design. Instead of hard wiring, the TurboCron cables for each cell are terminated with eight industrial grade hybrid connectors that between them include 75 Type J thermocouple contacts, 24 power contacts and 20 signal contacts. This makes it possible to replace an entire unit in no more than half an hour without the aid of an electrician. Summary Connectorization can save significant amounts of time and money in fabrication, installation, operation and maintenance of equipment of all types. When preparing to purchase, manufacture, or overhaul equipment, it would be worthwhile to think seriously about adding connectors at appropriate locations on wiring and cable runs, instead of hard wiring those connections. About the Authors Cory Jenkins is Product Manager, Value Added Business for HARTING in Elgin, IL. He has a Bachelor s Degree in Mechanical Engineering from Northern Illinois University, and more than 10 years of experience in the cable assembly and harness field. As Product Manager he oversees HARTING s Value Added Cable Assembly group in North America and has designed thousands of cable assemblies. He also has a wealth of connector application knowledge gained via on-site cable assembly installation, and also provides customer technical support from Elgin. He can be reached at cory.jenkins@harting.com. Richard Carlson is Senior Product Manager for HARTING North America. He has a Bachelor s Degree in Business Management from Elmhurst College of Illinois, and has more than 30 years of experience in the electrical connector field. As Senior Product Manager Rich manages HARTING s line of heavy duty industrial connectors in North America and supports the company s customers with his deep connector knowledge and expertise. He can be reached at rich.carlson@harting.com.

8 About The HARTING Technology Group The HARTING Technology Group was founded in 1945 and is now a global participant in the fields of electrical, electronic and optical connection, transmission and networking, as well as in manufacturing, mechatronics and software creation. From its earliest days the firm has been producing the rectangular connectors now know as the Han connector line. The Group uses its expertise to develop customized solutions and products such as connectors for energy and data transmission applications including, for example, mechanical engineering, rail technology, wind energy plants, factory automation and the telecommunications sector. For more information, visit