# Power requirement - 3 phase or single phase?

Discussion in 'General Electronics Chat' started by Tdawgg, May 19, 2012.

1. ### Tdawgg Thread Starter New Member

May 19, 2012
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0
I recently purchased a several hundred gallon tank for heating water for a brewing application. There is a Watlow immersion heating element that extends into the tank and the power box has the following on it:

AC Rating
120-277 V: 30 A
480V: 21 A

My assumption is that the 480V is three phase power. However given the range of 120-277V I was curious if this could also be operated off of single phase power with a higher amperage.

Any help you can provide on what kind of power could be used on this would be helpful!!! Also any benefit to one versus the other? Faster heating times or something similar?

Thanks!

Tyler

2. ### strantor AAC Fanatic!

Oct 3, 2010
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All a heating element is, is a high wattage resistor. Theoretically you could use any voltage. I assume your element has several posts with jumper links; this is how you set up series/ parallel single phase/ 3phase configurations. Could you post a pic? I'll be able to tell more.

3. ### Tdawgg Thread Starter New Member

May 19, 2012
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0
Attached is the picture of the wiring. Thanks for the help!

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4. ### dataman19 Member

Dec 26, 2009
136
29
you can wire an element across the phase making it a 208V (if you have 120/208 3-Phase power).
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The 208V will use less power for the same work.(considering how your electrical power factor is factored at the power meter - ie: 10 Amps at 120V equates to 5 Amps at 220V, but the meter factors it at 8Amps at 220V. (This is why you should always spread 120V high load devices in the fuse/CB Box. One side is 1/2 of the 220V home service, the other side is the other half).\
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3-phase has three power conductors, one common and a "ground". with 120/208 you have 120V from any phase lead to common (one hot), and 208V from any phase to another phase lead (both hot - similar to the European AC configuration - in the United states we have a common and a power lead).
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Dave
Phoenix

5. ### strantor AAC Fanatic!

Oct 3, 2010
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shoot, silly me, I was expecting I would see the heater, but of course it's installed through the wall of the tank, DOH!
Well by the way they have the one link that I can see installed, I would say that the top 2 are one tube, the one on the right + the one on the bottom right are another tube, and the other 2 form the 3rd tube.
As for the wiring, I can't tell what's what, or what that knob is. I tried googling that number on the knob and it's a phone number, not a part#. I assume it's a thermostat but how it works, I don't know.
Is this set up for 3phase?
Since there's only 3 tubes, I would think that for single phase you would want them all 3 in parallel, and I don't think that's how it's set up.
If you could make a diagram of where the wires go, that might help me give you some better info. Also a resistance measurement of the 3 tubes so I can determine the amperage in different configurations.

6. ### Tdawgg Thread Starter New Member

May 19, 2012
3
0
Thanks for the feedback and comments! I have attached a picture of the wiring diagram. There are three heating coils stacked on top of each other. The first coil runs across the top two terminals and then the next coil the second set of terminals. In the center is what appears to be a temperature probe.

I measured the resistance and it appears to be right about 20-21 Ohms for each of the heating loops. There are two of the links or bridges (My picture didn't show the second one very clearly as a wire was in the way.

I am looking for a small rental space to hook this up and ultimately need to figure out if having three phase power is preferable and if that is currently the way it is wired. If three phase would provide a much more efficient heating of the water then that is something I also would need to consider.

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7. ### dataman19 Member

Dec 26, 2009
136
29
It is wired for 220V...
Two hots and one common...
..
Dave
Phoenix, AZ

8. ### strantor AAC Fanatic!

Oct 3, 2010
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. If it were set up for 220v, where would you connect the wires? Hots to T2 & T3 and neutrals to C1.1 & C3.2?