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Strategies & Market Trends : Booms, Busts, and Recoveries

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To: maceng2 who wrote (65856)	7/3/2005 9:39:41 AM
From: Slagle	Read Replies (1) of 74559

PearlyButton Re: "415 volt three phase" Never heard of that one. Here we use 230/460 on dual voltage motors (tap the coils in parallel for the low volts or in series for the high). Here in the south there is lots of 550 volt three phase, the old textile industry voltage, and the thinking was that as weave rooms had wooden floors the higher voltage was acceptable. Many dual voltage motors are rated 208-230/460 and this means that they will work on either 208 or 230 on the low voltage tap. The purpose for the 208 volt service is that you are able to provide 115 volt single phase and a 208 volt three phase off the same transformer (line to line is 208v and line to neutral is 115v) and this is mostly used in grocery stores ect. Industry avoids this one as it is extremely inefficient. Some German equipment came over here 380 volt and there are some other ones. 415 must be a Brit standard. I ran a plant engineering and maintenance organization for many years and later I owned two different companies that built process equipment. Never paid much attention to any codes, didn't need to. You just use common sense. Lots of times you have to work on a system while it is hot. Lets say that you have a big finishing line with dozens of individual motor drives and a control console bigger than a large SUV and something goes wrong. You can't shut anything down because if you do you will loose many thousands of dollars worth of product and then have dozens of production workers sitting around on their duffs. You work on it hot. Sometimes you get "stung" as I have many times but it is no big deal. I have never heard of an electrician or anybody else for that matter in my industry getting hurt badly due to an electrical shock. I know more people who have been struck by lightning. Here we have the National Electrical Code that gets a revision every few years. In most locales it is being rigorously applied to all these new McMansions that are being built. That is a new development too as in most places there was no code inspection of any type till fairly recently outside the biggest cities. But in industry in most states you do absolutely as you like as there is no governing body to do the inspections nor would state politics allow it as a rigorous application of codes would make our industry uncompetitive. The guy who does the residental inspections for the town code office would be lost in your typical industrial plant anyway. There is a trend toward more regulation and code enforcement in some places here, but it is mostly in your "rust belt" type place where industry is dying anyway. And the codes and the rest are part of the reason. What I have seen in Asia is that they use the best features of the old American system. They use what ever practice they desire and whatever works best without regard to any code or regulation. This allows the technical people to build up the most efficient system using any mix of compontents and devices from anyhwere. They don't have a UL type mafia in the shakedown business over there. They extend it to residental practice there too, using very nifty devices the design of which originated in Japan years ago and has matured over the years in places like Taiwan. None of that stuff can be used here. We are stuck in the 1920's UL mandated rut. But industry here in the states, for the most part is still free. Their fridges are 220 volt two wire, no ground. Slagle

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