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New inverters earn $47,781 utility rebate: some people have a higher threshold for pain than others. Norman Vautour is one of them. (Welding/Brazing/Soldering).

As production supervisor at Woods Equipment Company's Gardner, MA facility, Vautour was responsible for maintaining 18 ancient GMAW welding systems. Through his tireless efforts to fight downtime, the company continued to meet the demand for its Woods Wain Roy(r) brand buckets and grapplers for excavators and tractor loader backhoes.

Woods Wain Roy quick-change coupler systems permit changing attachments in a matter of minutes; operators don't even have to leave the cab when using the hydraulic version. Since the 1970s, Wain Roy quick-change equipment has helped contractors be more productive.

However; it wasn't until May, 2002 that a change at Woods eased Vautour's pain--and improved productivity by 10% while earning a $47,781 rebate from local utility company Mass Electric. The improvements occurred when welding distributor Liberty Supply Inc. (Leominster, MA) installed efficient and reliable XMT[R] 456 and Invision[R] 456MP inverter power sources and 70 Series wire feeders from Miller Electric Mfg. Co.

Power Savings

The XMT 456 is a multiple process (Stick/TIG/MIG/flux cored/gouging) power source with a 5--600 amp welding output. The Invision 456MP is also a multiple process power source (Stick/MIG/flux cored/gouging) with a 5--600 amp output, but it features built-in controls for pulsed MIG, 18 factory-set pulsed MIG programs and one manually set pulsing program. The Invision 456MP is the easiest, most cost-effective industrial inverter to use for pulsed MIG.

Most importantly, the XMT and Invision have an average power efficiency of 85%. Where Woods' old machines drew 16 kW while welding with a 0.045" diameter E70C-6M metal cored wire, the XMT and Invision draw only 9 kW. Depending on the function (fabrication or tacking) and whether they were used for one or two shifts, Mass Electric calculated that these inverters would save 1,599-65,542 kWh per year, per machine. Total power reduction was an estimated 111,407 kWh annually, which lead to the rebate.

"The fact that Liberty Supply showed us how to obtain a rebate that paid for half of the 18 new welding systems made upgrading too enticing to pass up, even in an uncertain economy," says Bob Latour, Woods' Gardner plant operation manager.

In addition to the rebate, the new inverters will lower utility bills by an estimated $9,692 annually.

"We've seen already our kilowatt usage drop," notes Latour. "The plant was using as much as 91,000 kW per month. After installing new inverters in May 2002, we used 87,000 kWh. It dropped to 81,000 kWh in June. The inverters are the biggest reason for the change."

Frustration and Downtime

While built to last decades, welding power sources have a finite lifetime. Woods continued to use its Hobart Mega-Flux and Excel-Arc welding systems beyond their reasonable life span in a high arc-on time application.

"The newest welding power source we had was made in 1981," says Vautour. "These old machines were constantly breaking down and we'd have to remove the machine from the cell and move another in. As a result of daily fluctuations in the output power, the welding wire frequently burned back into the contact tip. Between moving machines, burnbacks, and grinding out bad welds, each fabrication operator lost an estimated 45 - 60 minutes per day of production time."

Liberty Supply representative Chris Kimbar adds that, "Old welding power sources often run hot one day and cold the next, nor do they have they ability to compensate for 'dirty' primary power. That's why Woods' operators spent a lot of time adjusting weld parameters and grinding out weld defects. Any time output voltage or amperage fluctuates, it affects the appearance or integrity of the weld because a welding wire needs to run within its proper parameters."

These problems and others meant weekly trips to Woods for Liberty Supply service technician John Matarese.

"I would go to Woods to replace rectifier fuses or install new or rebuilt boards," he says. "Sometimes it would be simple things like checking that the drive roll matched wire size or cleaning the bolts on the transformer voltage links. A lot of people don't realize that failing to clean carbon off the bolts can cause one leg of the power to be weak, which in turn over works the other two legs, stresses their SCRs (rectifiers), and reduces their service life."

Matarese notes in the last few years of the old machines' life he replaced six to 10 auxiliary transformers per year.

"Because Woods constantly shifted machines from station to station to provide operators with a working machine, the voltage links were sometimes set for 240 V power and accidentally plugged into 460 V primary or vice versa. That causes the auxiliary transformer to fail with a nice, loud popping sound."

Upgrading To Inverters

Efforts to squeeze another year of service from an old power source are the rule rather than the exception among many manufacturers and fabricators. Even though an old machine causes downtime, the prevailing mentality is "but it still welds." People like Kimbar are helping to change that mindset. By showing companies like Woods how today's inverter power sources and digital wire feeders increase productivity and quality, justifying the capital expense has become much easier (see Figures 1 and 2).

"When older welding equipment goes down, a company's assets are sitting idle," says Kimbar. "We help companies understand the value of uptime offered by new welding equipment and equate that to getting more product out their door."

Operations Manager Latour notes that "Since we purchased the new welding systems there is less of a need for overtime. Our fabricators get about 10 percent more work done during their regular shift."

Woods' fabricators also appreciate equipment that makes their life easier.

"The trigger hold function on the wire feeder really saves my wrist, and I weld for about five hours out of an eight hour shift," notes Jay Austin. Most of the buckets Austin welds have four 2' - 3'-long welds for welding on the mold board and side leading edges. "I like the feeder's four drive roll system because the wire doesn't hang up. On the power source, the digital readout is nice because I can view settings at a glance. I always had to tweak the wire feed speed or voltage on my old system because it ran differently from day-to-day. It's easy to see now, but I don't have to change it much anymore. With the new inverter, I just turn it on, start welding and continue to make clean welds all day long."

Power Savings Spread

While increased productivity, better weld quality and better uptime will, in the long run, provide a greater payback in energy savings, the utility rebate was the catalyst for change at Woods.

"The upgrade would not have occurred all at once," says Vautour. "It would have been spread over a couple of years, replacing the older machines two or three at a time." Latour adds that, "Through the energy efficient welding systems, we connected with Mass Electric's savings programs for things like lighting, air conditioning, and compressors. None of this would have happened if it wasn't for Miller Electric equipment and the knowledge of Liberty Supply." Miller Electric Mfg. Co.

www.rsleads.com/212mn-209 or Circle 209 for more information
New Inverter Power Sources Solve Welding Problems

Old Power Source New Inverter
Limitation/Problem Advantages/Solution

Inefficient use of primary Efficient use of power
utility power increases factor lowered Wood's
utitlity bills utitlity bills by 10%

Poor power factor may lead Excellent power factor
to utility penalties may lead to utility rebates
 (50 % of purchase for Woods)

Primary power fluctuations LVS[TM] line voltage
affect welding arc, weld compensation technology,
quality and create Auto-Line[TM] technology
burnbacks maintain steady output power

Transformer jumpers Automatic linking
must be correctly linked technologies (e.g.,
or transformer fails Auto-Link[R] and Auto-Line)
 eliminate needs for
 manual linking

Large, heavy (500+ lb.) Small, light (118 lb.--fits
 on workbench)

Many control knobs - more East-to-understand
difficult to learn to use interface - one process
for simplicity and accuracy select switch, digital
 meters

Not good for pulsing, Best for pulsing; Invision
no ability to store "MP" inverters store
pulsing programs 18 pulsing programs

Perform a single welding Multi-process output
process (CC or CV only) (CC/CV) without arc
 quality compromise

Not reliable (downtime), Very reliable (Woods
high maintenance costs increased production by
 up to 10 percent), parts
 covered by three-year
 manufacturer warranty

Cooling fan motors run Cooling fan only runs
constantly - noisy when needed
work space (Fan-On-Demand[TM])

New Wire Feeders Solve Welding Problems

Old Wire Feeder Limitations New Wire Feeder Advantages

Worn drive rolls cannot maintain Four all-gear-driven drive
tension, leading to feeding rolls grip and feed the wire
problems (and over-tensioning the positively. Easy to set proper
rolls deforms the wire) tension for good performance

Operator fatigue Trigger hold function lets
 operator relax index finger
 during long welds (was
 optional, now standard)

Poor arc starts Automatic run-in control
(burnbacks or stubbing) (adjusting wire feed speed lets
 arc establish itself)

Harder to view proper Digital meters (was optional, now
weld parameters standard on digital models)

Severe bends in wire path reduce Toolless (built-in T handle)
gun liner life, may cause rotatable drive assembly tilts
erratic feeding to eliminate bend

Poor arc starts, crater cracking Sequence control (deluxe models
 only) provides complete control
 up-slope, down-slope and other
 weld parameters

Weld parameters inconsistent Range control (deluxe models only)
between operators; cannot lets supervisor lock parameters
guarantee welding within within set range
customer specs

Fine-tuning arc takes time when Weld program storage (deluxe
changing wires, positions or models only) allows instant
applications recall of preferred or
 established weld parameters
COPYRIGHT 2002 Nelson Publishing
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2002 Gale, Cengage Learning. All rights reserved.

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Publication:Modern Applications News
Date:Dec 1, 2002
Words:1607
Previous Article:Oil separator with bag filter. (Spotlight Products).
Next Article:Robot increases welding speed 350% on high-precision, thin aluminum cases. (Welding/Brazing/Soldering).


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