Exclusive: Eaton/Cutler-Hammer introduces IT contactors and starters with all 24 V dc control, MCCs, and more
Milwaukee, Wis. - Focus on 24 V dc for control power expands into new electromechanical contactors and starters just introduced by Eaton Corp.'s Cutler-Hammer business unit. They're part of Phase 2 in an evolving program called Intelligent Technologies (IT), with the goal to develop various efficient, cost-effective power control products.
Milwaukee, Wis. - Focus on 24 V dc for control power expands into new electromechanical contactors and starters just introduced by Eaton Corp.'s Cutler-Hammer business unit. They're part of Phase 2 in an evolving program called Intelligent Technologies ( IT ), with the goal to develop various efficient, cost-effective power control products.
The IT. Electro-Mechanical (EM) line consists of microprocessor-based contactors and starters - reversing and non-reversing - which incorporate solid-state overload relay protection. NEMA and IEC-type units are offered, however package size reductions made possible by the low-voltage control is most dramatic in the IEC-type devices.
NEMA models come in sizes 00 to 5, with ratings of 9-270 A continuous and 1.5-200 hp max., at 60 Hz and various supply voltages from 200 to 600 V (3-phase). For single-phase input, 1/3-15 hp units at 115/230 V are available. The present lineup for IEC-type contactors and starters comprises frame sizes A to F (27-140 mm width), with 3-400 A max. AC-3 rating and 0.75-250 kW max., at 50/60 Hz and supply voltages from 220 to 575 V (3-phase). Power and current ratings will increase to 1/4-900 hp and 6-1,250 A, respectively, as the full product line fills out later in 2002.
24 V dc control at the core
IT. Electro-Mechanical contactors and starters continue the company's ambitious Intelligent Technologies program that began in 1999 with a family of solid-state reduced voltage starters called IT . Soft Starts, (CE, July 1999, pp. 9-10; www.controleng.com/archives/1999/ctl0701.99/ctl9907tu.htm .)
Low-voltage control power characterizes the entire IT . product line. The approach goes well beyond reducing the physical size of products. Use of 24-V dc control brings added reliability and safety, as well as easier regulatory compliance. Incorporating low-voltage power supplies adds capacitance for voltage regulation and ride-through. The latter feature is vital for limiting the drop out of equipment in a manufacturing line during power disturbances. Voltage ride-through also eases compliance with the European Union's Machinery Directive, while the EU Low Voltage Directive (which starts at 75 V dc) can be met by definition. In the U.S., 24-V dc control simplifies meeting NEC and OSHA regulations.
Still other benefits arise from using globally accepted 24-V dc control versus higher voltage ac control. There is no need to transform a variety of ac supply voltages used worldwide, thereby minimizing application and support issues, according to Matt J. Polk, Cutler-Hammer product line manager for IT Power Control.
However, making 24-V dc motor control practical in severe industrial environments was no easy matter. It took a long-term development by Cutler-Hammer to ensure that low-voltage control would work reliably around high currents and power draw.
At the heart of IT . EM devices is the 24-V dc coil. It provides reduced contactor arcing, balanced magnetic field, high contact force, reduced heating, and longer ride-through. Besides allowing smaller enclosures, low-voltage control saves on wiring and is safer for people working on the equipment. Also, users can change the device's motor protection level by selecting either Trip Class 10, 20, or 30. This eliminates the need to inventory individual trip class part numbers.
Mr. Polk lists several other 'exclusive' features of IT . Electro-Mechanical products. For example, pulse-width modulation (PWM) technique is used to minimize the dc value generated in the contactor. This reduces energy reflected to the contact block, thereby yielding much smaller contactor sizes.
The design of IT . EM products eliminates traditional wiring between the contactor and overload relay, as well as the seal for auxiliary contacts. To minimize nuisance trips, sensitivity settings for phase loss and phase current unbalance are user selectable. An operating ambient temperature range of -40 to 65 °C is also said to be special.
Although 24-V dc control is exclusive to the IT product line, Cutler-Hammer will maintain some existing starter/contactor products for customers who want 120-V ac control, explains Mr. Polk.
New MCCs, communication architecture
Today's technology advancements leave no segment of industrial automation behind - motor control centers (MCCs) are no exception. Phase 2 IT . products include new MCCs with a compact redesigned structure derived, in part, from the 24-V dc bus for control. Size reduction amounts to 30-40% smaller than current MCC models. Redundant power supplies and DeviceNet communications are also built in. Just one network drop is required per MCC unit.
Looking ahead, each MCC 'bucket' will be addressable via the web over Ethernet for access from higher level controls. This capability is expected to be available later this year. Wireless communication may be another future option.
Other IT . MMC features include an integrated breaker control, integrated field I/O points, comprehensive motor data, and a choice of eight starter control/status indicator layouts.
Functions programmable in software are also part of the new MCCs. 'Programmability allows us to build individual MCC buckets as standard units, yet enables us to produce and ship a motor control center that's actually a custom product,' says James Kinsella, business unit manager for IT Products.
Support software, system 'wellness'
A single software suite provides device configuration and monitoring functions for IT . products. The scalable software, named CHStudio, offers configuration management and an integrated library of device support documentation. It comes in two versions: CHStudio-Component Manager, available now, can access, monitor, and configure any DeviceNet component supported by an EDS file. CHStudio-MCC Manager - coming in June 2002 - will perform similar functions for motor control center assemblies.
The launch of IT . Phase 2 products started in early March 2002, with additional products to be rolled out during the year. Later phases of Intelligent Technologies will add the capability to monitor the condition of equipment and processes connected to motors. For example, factors such as efficiency, uptime, power sensing, and safety issues will be monitored. Mr. Kinsella refers to these upcoming developments with such terms as 'health of equipment' and 'system wellness.' They reflect a broader, holistic approach for bringing advancements to intelligent power controls. For more information, visit www.cutler-hammer.com .
Control Engineering Daily News Desk
Frank J. Bartos, executive editor