Buy Or Build Your Own Phase Converter

Buy Or Build Your Own Phase Converter FARM SHOP Miscellaneous Stan McDonald will build a 3-phase converter for you or tell you how to build your own Three-phase electric motor driven tools cost less are more energy efficient and last longer than single-phase motors The problem is that retrofitting or installing a 3-phase system is costly     “The converter turns a standard single-phase system into an artificial 3-phase system ” says McDonald “Three-phase equipment can often be purchased surplus and is of higher quality than new single-phase consumer grade equipment ”     Standard power cycles up and down with full power delivered at the peak in the cycle It requires only 2 conductors wires a phase conductor and a neutral conductor With a 3-phase system 3 conductors each carry alternating current of the same frequency and voltage amplitude     Power going through each conducting line is “phased” to reach its peak one third of the cycle behind and ahead of other conductors This means that a motor is getting a more even supply of power than with a single line cycling up and down from peak to valley It also means that a 3-phase line can carry 3 times as much power     “The phase converter artificially generates the third leg of a 3-phase system using the 2 conductors of a single-phase system ” says McDonald “It’s not a perfect transformation but it gets the job done ”     Converters have gotten the job done for McDonald who started out with the goal of establishing a machine shop He picked up heavy-duty 3-phase lathes milling machines and more from schools that were downsizing their shop class offerings     “I bought a lathe for $752 a vertical mill for $350 and horizontal mill for $650 ” says McDonald “A new vertical mill would have cost something like $17 000 and a horizontal can cost $20 000 ”     One of his best deals was a 21-in lathe that was 6 to 7 ft long and weighed around 5 000 lbs He got it for the cost of transporting it out of the school and to his shop     “I brought it home hooked a phase converter to it and was ready to go ” says McDonald “I made more on the first job I did with it than the transporting cost ”     When he bought his first 3-phase mill McDonald bought a commercial grade static phase converter When it didn’t work right he first called the company When they didn’t help he tore it apart and found paper and cardboard in the converter which he says is illegal     “I built my own static converter hooked it up and it ran great ” says McDonald “A customer saw it and said why don’t you build them but I wanted to build parts not converters ”     In the years since McDonald has added 3-phase equipment to his shop some purchased and some he built himself Vol 26 No 4 and Vol 40 No 6 He has also continued building phase converters     “FARM SHOW readers who run bigger equipment should consider getting 3-phase motors to reduce their costs ” says McDonald noting that large 3-phase motors can be extremely cheap “I got a brand new 15 hp motor still wrapped in plastic for $10 at a local surplus equipment dealer I bought an industrial 3-phase welder for $25 because no one wanted it It would have cost $8 000 new I spent $75 for a rotary converter and another $100 in parts ”     McDonald insists that the average person can build his own phase converter with surplus components He will provide plans that outline what needs to be done or build a customized converter as needed The cost varies with the type of converter the size and voltage of the motor     “I just built a variable frequency drive for a guy with a 7 1/2 hp motor and oddball voltage ” says McDonald “It cost about $850 which is less than a conventional phase converter would have cost ”     Contact: FARM SHOW Followup McDonald Enterprises 402 Mudcat Rd Foxboro Ontario Canada K0K 2B0 ph 613 968-9516; smcdonal@kos net

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