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Southeast Minnesota | We are thinking about upgrading our corn dryer from a pto to electric. Most newer dryers are three phase. We only have single phase at the drying setup. We would possibly need to start a 20 or 25 hp motor with another 10hp and maybe some small others. We have no experience in this field of electricity. What do we need to know about phase converters?
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| Get a variable frequency drive (VFD). When you have single phase power they are the best option for 3 phase fan motors. A 25 HP drive will power a 25 HP fan motor. If you need to power an auger or other similar load with a 3 phase motor, then the VFD needs to be double the size of the motor. I don't really know how all that electrical stuff works, but I do know that once the magic smoke comes out, it won't work anymore. Check with CMC in Fargo for the VFD. |
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Northern Indiana | A VFD is best suited for one motor.
I would assume that you will need to run several motors at a time or have several coming on and off at different times. This is where a converter would work best.
True. Cant seem to put that magic smoke back in. |
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Gilby,ND | id recommend cmc in fargo too. We just ordered a VFD from them to Run our 20 HP Air System Motor. They are very knowledgeable and helpful. |
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Central Iowa | This situation i would recomend a rotory phase convertor. I would also strongly recomend getting a converter that has 2x the hp of all the motors it will be starting all at the same time. So if the dryer has 2 25hp fans on it i would recomend a 100 hp phase convertor. That will aid in starting and also will leave you extra room for any of the smaller motors on the drier. |
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Sac & Story county IA | A rotary phase converter is basically an induction motor operating on single phase power that acts as a rotary transformer and produces power on the third winding that can be used to operate a load motor. The phase converter output is tuned with oil filled capacitors to achieve the best voltage balance.
I have built and used them for more than 20 years. The problems are about the same as with any other motor setups. Mice getting in and eating insulation, water getting in a motor, bearing drying out, contactor points getting dirty and corroded, ad infinitum.
The other benefit from a phase converter is the ability to use 5, 7 1/2, 10 hp motors on loadout motors. Used motors are usually really cheap on the scrounger market. Plenty of contactors on ebay.
I do think vfd's are wonderful. I use several. But the workhorse of a grain drying and handling facility is a large idler motor making 3 phase power. |
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South Dakota | I was told with a phase converter only has to be as big as your biggest motor if you state that one first as it will also act as a converter . |
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Winkler, Manitoba Canada | You need to talk with your local electrical utility about your electrical service. Single phase service may be limited in size and as a result your phase converter size will also be limited. This may limit the size of three phase motors that you are able to run. Locally I seem to be locked into using VFD drives as my utility wants to limit inrush current to very low levels. With the VFD drive you can program in a very soft start by having a 15 or 20 second ramp up to speed which eliminates the big inrush current spike. |
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NW ILLINOIS | We built our own phase converter many years ago and it works great.
Then a customer came to us and needed something more demanding.
These people helped us out and were very knowledgeable.
http://www.andersonconverters.com/
Been in business many years
olf20 / Bob |
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| Do you have 3ph power close to your bin site? The reason I ask is we have 3ph power running in front of our bin site but were always told that the power company wouldn't put it in however this summer my brother made some phone calls and after getting ahold of the right person at the power company we can get a 3ph service installed big enough to run 200hp worth of motors for around $2,200 and that includes running the lines 300' off the road on our property. |
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SW Ohio | I've heard that too. I think it only applies to a small "get-by" set-up. It may work but not as long nor as efficiently. There is also a limit to the total HP that can run on a single rotophase. I have a second one that I can start if the HP starts adding up. Don't need it since Dad quit the elevator business. |
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midwest | Lucky Duck.:-) You need twice the capacity convertor to start your largest motor. I put in a 40hp air system motor on my drying setup which in turn I needed a 80hp convertor. Once I started that motor I then could start some smaller ones, like the wet corn auger at 10hp 3ph etc... |
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Leesburg, Ohio | Check the following link, and call them. This is what we use, and there are many in our area on grain setups.
http://www.arco-electric.com/Product.aspx?ProductID=2
Ours is a model 30, I think. Runs a 20 hp leg, 15hp pit, and several 5 to 10 hp auger motors. Still room on it for a 20hp air system that we plan on changing over from single phase.
Edited by KDD 8/24/2009 13:22
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tell me about three phase converters
