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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
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3-phase vs single-phase heating elements
Figured you guys would know...
I have found a used 220 v 3-phase oven that I would like to use in my shop. The problem is that I only have 220v single phase. Without going to a phase converter is there a way I can run the oven off of single-phase by re-wiring the heating elements? IOW...how would I reconnect to single phase to not overload the elements but also give me the heat I need? (Oh, even though I'm fairly electrical-challenged I did some homework and learned that there are two basic ways 3-phase elements are wired, star and delta. I just don't have enough knowledge of AC circuits to figure out how to swap the elements or if it's even feasible.) |
#2
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3-phase vs single-phase heating elements
I rewired an infrared 220 3 phase heater. it had three elements. one between
L1-L2, one between L2-L3, and one between L1-L3, Yours is likely the same. I ran three single phase 220 circuits, one to each element, worked fine. Karl |
#3
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3-phase vs single-phase heating elements
On Aug 18, 2:36 pm, "Karl Townsend"
wrote: I rewired an infrared 220 3 phase heater. it had three elements. one between L1-L2, one between L2-L3, and one between L1-L3, Yours is likely the same. I ran three single phase 220 circuits, one to each element, worked fine. Karl Good info. I did some more homework and it looks like I could do this but my amperage would go up 1.73X (sqrt 3) as much. How about this idea- after I rewire to single phase can I run three breakers, one for each element, and then turn each on one at a time so that I don't spike my power? I have 200 amp service to my shop and each breaker would be 50 amps. The unit as 3-phase is 30KW at 220V for a 3-phase amperage of about 79 amps. With single phase I would be looking at about 137 amps, hence the three 50 amp breakers. How practical is this in a home shop? The other question... each element sees the same voltage but what about the same power and will it kill my elements? |
#4
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3-phase vs single-phase heating elements
It all depends on how they are wired. It may or may not be easy to
rewire. Open the case and look. Even if they are delt wound (forming a triangle), you may get 2/3 of power from them. i |
#5
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3-phase vs single-phase heating elements
I'll defer to the electrical gurus that will chime in...
start with the basics. measure the resistance of a single element. Divide into 220 to get amps. V=I*R V/R=I. That's a big heater, you may want to run only two elements. Karl |
#6
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3-phase vs single-phase heating elements
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#7
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3-phase vs single-phase heating elements
On Aug 18, 1:30?pm, wrote:
Figured you guys would know... I have found a used 220 v 3-phase oven that I would like to use in my shop. The problem is that I only have 220v single phase. First of all determine if the heater elements are 220v or 110 volts. If they are 220 your unit is probably wired delta. If 110 volts then WYE. They are marked somewhere. Also determine the KW rating of each heater element. Remove all the wiring. If the elements are 220 then wire each individually to a 2 pole 220 volt breaker. No neutral needed. If 110 volts then wire each individually to a single pole 110 volt breaker. A neutral will be needed. As another said watch out for the neutrals. If you end up wiring for 110 volts make sure you wire them to alternate hotlegs of the 220 single phase in your panel. Don't make the neutral wiring smaller than any 110 volt wiring. Also any wiring within the heater must be, HPN I believe it the word, IOW high temperature rated. And the terminals on the heaters also heat rated. (I am not up on the wire and terminal types.) I am guessing here but I would imagine that this heater is too much for the 220 single phase service you have to your shop. An upgrade might be in order. Bob AZ |
#8
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3-phase vs single-phase heating elements
On Aug 18, 5:52 pm, Bob AZ wrote:
On Aug 18, 1:30?pm, wrote: Figured you guys would know... I have found a used 220 v 3-phase oven that I would like to use in my shop. The problem is that I only have 220v single phase. First of all determine if the heater elements are 220v or 110 volts. If they are 220 your unit is probably wired delta. If 110 volts then WYE. They are marked somewhere. Also determine the KW rating of each heater element. Remove all the wiring. If the elements are 220 then wire each individually to a 2 pole 220 volt breaker. No neutral needed. If 110 volts then wire each individually to a single pole 110 volt breaker. A neutral will be needed. As another said watch out for the neutrals. If you end up wiring for 110 volts make sure you wire them to alternate hotlegs of the 220 single phase in your panel. Don't make the neutral wiring smaller than any 110 volt wiring. Also any wiring within the heater must be, HPN I believe it the word, IOW high temperature rated. And the terminals on the heaters also heat rated. (I am not up on the wire and terminal types.) I am guessing here but I would imagine that this heater is too much for the 220 single phase service you have to your shop. An upgrade might be in order. Bob AZ Yes, I agree. It is important to determine if the elements are for 220V or 110V (3 phase makes it 08V live to live), it makes a big difference. From a different angle, 137 A power draw may be a little high for a typical home. You may need to make sure your main breaker can take it. Ken Opportunities are never lost. The other fellow takes those you miss. | Torrey Hills Technologies, LLC | | www.threerollmill.com | | www.torreyhillstech.com | |
#9
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3-phase vs single-phase heating elements
Torrey Hills wrote: On Aug 18, 5:52 pm, Bob AZ wrote: On Aug 18, 1:30?pm, wrote: Figured you guys would know... I have found a used 220 v 3-phase oven that I would like to use in my shop. The problem is that I only have 220v single phase. First of all determine if the heater elements are 220v or 110 volts. If they are 220 your unit is probably wired delta. If 110 volts then WYE. They are marked somewhere. Also determine the KW rating of each heater element. Remove all the wiring. If the elements are 220 then wire each individually to a 2 pole 220 volt breaker. No neutral needed. If 110 volts then wire each individually to a single pole 110 volt breaker. A neutral will be needed. As another said watch out for the neutrals. If you end up wiring for 110 volts make sure you wire them to alternate hotlegs of the 220 single phase in your panel. Don't make the neutral wiring smaller than any 110 volt wiring. Also any wiring within the heater must be, HPN I believe it the word, IOW high temperature rated. And the terminals on the heaters also heat rated. (I am not up on the wire and terminal types.) I am guessing here but I would imagine that this heater is too much for the 220 single phase service you have to your shop. An upgrade might be in order. Bob AZ Yes, I agree. It is important to determine if the elements are for 220V or 110V (3 phase makes it 08V live to live), it makes a big difference. From a different angle, 137 A power draw may be a little high for a typical home. You may need to make sure your main breaker can take it. Ken Opportunities are never lost. The other fellow takes those you miss. | Torrey Hills Technologies, LLC | | www.threerollmill.com | | www.torreyhillstech.com | YOur household electric stove and oven doing a Thanksgiving dinner takes more than a small heat treat oven. Its not a car bottom heat treat oven I hope. My 12 x 12 x 20 inch 2000 degree F oven is less than 5000 watts. That is only roughly 25 amps at 220 volts. John |
#10
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3-phase vs single-phase heating elements
On Aug 18, 6:02 pm, wrote:
On Aug 18, 2:36 pm, "Karl Townsend" wrote: I rewired an infrared 220 3 phase heater. it had three elements. one between L1-L2, one between L2-L3, and one between L1-L3, Yours is likely the same. I ran three single phase 220 circuits, one to each element, worked fine. Karl Good info. I did some more homework and it looks like I could do this but my amperage would go up 1.73X (sqrt 3) as much. How about this idea- after I rewire to single phase can I run three breakers, one for each element, and then turn each on one at a time so that I don't spike my power? I have 200 amp service to my shop and each breaker would be 50 amps. The unit as 3-phase is 30KW at 220V for a 3-phase amperage of about 79 amps. With single phase I would be looking at about 137 amps, hence the three 50 amp breakers. How practical is this in a home shop? The other question... each element sees the same voltage but what about the same power and will it kill my elements? Careful here. Make sure it's not 'center tapped` , Wye connected Thats 120V. per coil. If so 240V. will fry it. But it can be wired for separate 120V. Lines. If the coils are wired delta, phase to phase then, If it's 3 Phase, and t's sized at 208V. Design is : 10 KW. , 40 A. / Coil What you are supplying is 240V., so you'll get : 11.5 KW. , 46A. / Coil. |
#11
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3-phase vs single-phase heating elements
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