INVERTERS, COST SAVINGS AND ENERGY BENEFITS?

 

 

In the September Welding Journal, an article was presented titled "Cashing in on the benefits of inverter technology " The article was written or presented by a "sales rep" who worked for Miller Electric Mfg. Co. As with many articles presented by welding equipment manufactures the information presented did not provide the complete story, and of course the article bias was on one of the so called cost benefits of an Inverter power source. I present the following data from another point of view.

The Journal article was about a pipe and tank fabricator who had approximately 50 multipurpose CC/CV welding units. The fabricator was changing their "13 year old" CC/CV equipment for Miller, multipurpose XMT Inverters. The companies "13 old" welding equipment was creating repair and downtime issues.

Without question welding Inverter power sources provide superior electrical efficiency in combination with a superior power factor to traditional none electronic MIG/TIG equipment. However if a fabrication company is looking for "cost savings" as a result of these factors, they should also give consideration to other factors that effect welding quality and costs.

COSTS. The fabricating company will eventually replace 50 power sources with the Miller XMT's, at a cost of approximately $3400 per unit. 50 x $3400 = $170.000.00 A (none inverters) CC/CV unit typically cost $2100 x 50 = $105.000.00 . With the $65.000.00 saving this company could purchase another 31 welding units or better still buy a robot.

DURABILITY. A primary issue for this company may be the Inverter durability and the ease of repair. In the welding article, emphasis was placed on how the old CC/CV equipment was costing money in repairs and down time. However the original low cost CC/CV weld equipment had in reality served this company for thirteen years. After eight and nine years the weld equipment started to have switch, board, and fan issues.

For nine years most of the CC/CV weld equipment was trouble free, while in contrast with inverters many companies have not been able to last nine months without electronic issues.


HOW LONG WILL AN INVERTER LAST WITHOUT EQUIPMENT ISSUES ? MOST INVERTERS STRUGGLE TO GET THROUGH THEIR 36 MONTH WARRANTY. INVERTER EQUIPMENT FAILURES ARE SO COMMON THAT THE WELD EQUIPMENT MANUFACTURES ARE FOREVER "EVOLVING THEIR INVERTER AND PULSED EQUIPMENT" WITH ELECTRONIC BOARD CHANGES.


The vast majority of MIG, CV welding power sources found in North America welding shops are traditional none inverter equipment that contain minimum electronics. The vast majority of power sources found in any weld equipment repair shop are inverter and pulsed equipment.


In the "before inverter welding days", a power source manufacture would manufacture a CV MIG power source, and typically that power source would remain unchanged for more than a decade. These days with so many weld equipment, ELECTRONIC issues, the power source you purchase today will likely not have much in common with the power source you purchase 12 months from now. Remember with the numerous, weld equipment changes we are not talking about "weld process evolution". When the weld equipment is changed, it's changed to correct electronic issues that result with the welding equipment.

LOST PRODUCTION. So you have had your inverter power source for 40 months, the equipment warranty is up, and you saved a little on the electric bill. It's Monday morning, time to get welding and the inverter power source wont work. The first thing you may realize is that the maintenance electrician your company pays $20/hr to, cannot repair the Inverter. Lets face the electrician is lost in the numerous maze of circuit boards. The weld equipment has to be sent out for repairs, its gone for two weeks and of course the electronic board that needs replacing will cost at least $1000 plus labor and shipping.

WHAT'S THE LOGIC OF HAVING WELDING EQUIPMENT IN A PLANT THAT CANNOT BE REPAIRED BY THE HIGHLY PAID MAINTENANCE PERSONNEL. WHAT IS EVEN MORE ILLOGICAL IS THAT THE PARAMETER OUTPUT AND RESULTING ARC CHARACTERISTICS OF MOST INVERTER CC/CV MULTIPURPOSE POWER SOURCES ARE INFERIOR TO A LOWER COST TRADITIONAL CV OR CC POWER SOURCE. HOW MANY COMPANIES BUY A MULTIPURPOSE CC/CV POWER SOURCE ONLY TO USE IT FOR CV APPLICATIONS. A SIMPLE CV POWER SOURCE WOULD HAVE COST LESS AND PROVIDED SUPERIOR PERFORMANCE.

In conclusion. Few companies will see a measurable cost savings in their electric bills, especially those companies that are billed on "peak demand" and have other high energy equipment such as plasma cutters on the shop floor. If savings are generated what's the benefit of saving $200 - $300 a year on your electric bill, if three or four years after the equipment is purchased you have a repair bill of $1200 for one power source. What's the benefit of having welding equipment in your plant that will provide a shorter life span and cannot be repaired by your maintenance personnel?.

Who really benefits from INVERTERS perhaps, those companies who have no floor space and need smaller equipment, maybe its the power company that provides the electrically, or perhaps it's the welding distributor and power source manufacture who make more profit on higher cost electronic power source.

WELDING POWER SOURCE PRICES HAVE RISEN BY 50 TO 300% IN THE LAST DECADE. COMPUTER PRICES HAVE DECREASED BY 300%. WITH THE INFUSION OF ELECTRONICS INTO WELDING EQUIPMENT WHY DO THE WELDING POWER SOURCE PRICES KEEP RISING?


ITS NOT THE POWER SOURCE ITS THE PEOPLE.
Many companies who purchased inverters and pulsed power sources quickly realized that the welding issues on the shop floor were not resolved with the purchase of more costly electronic welding equipment. Electronics are necessary for specific welding equipment just as pulsed is necessary when welding gage aluminum. However for the vast majority of "manual", carbon steels and stainless applications I emphasize that there are no welding quality or weld productivity benefits that are attained from electronic inverters, pulsed welding equipment or STT power sources.

As a process control engineer I have worked on some of the most sophisticated welding equipment and robots in the USA. I have also worked on some of the worlds most difficult automated welding applications. I am aware of the importance of electronics. I am also aware of the lack of weld benefits derived from the superficial electronic bells and whistles that are offered on welding equipment, bells and whistles that try to justify the ridiculous prices required for pulsed MIG equipment.

I recognize the fact that the power source manufactures have found gold in electronic circuit boards and that its easy for them to keep raising the weld equipment prices when the weld equipment offers more electronic features. I also recognize that during the next decade it may be difficult to purchase the lower cost CC or CV traditional welding equipment. However this site deals with weld reality and the bottom line is this. The less costly, more durable, more reliable traditional CV welding equipment that has been available since the 1960's can with "people weld process expertise" meet any weld code requirement. This equipment is still therefore the best buy for most welding shops.

When you read your next welding article in that magazine, give consideration to natural bias of the article source. Think twice before you invest in unnecessary electronics and remember a sales rep is a sales rep.