Transformer Phase Current Imbalance

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Shells

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So I have a 9kVA, 480V, 3-phase 208-120V encapsulated transformer located outdoors. Currently each phase is barely loaded, P1-420W, P2-420W, P3-120W. I would like to add a 3600W load to this transformer since it is the nearest power source. The cost overuns would be significant if I would have to build scaffolding and run cables from a remote location. My concern then is the phase current imbalance. I would now have at best one phase being at least 8 x loaded that the other 2. There is no way I can adjust the loads to achieve current balance. Since the transformer would still be only about 50% loaded I am not sure if the heating effects will be significant. In the interest of cost, it is sufficient to say that I can add the load as planned, measure the phase current on installation and perform periodic infrared scans to detect any overheating. If overheating is observed, I can install a bigger transformer to handle the overheating. Any comments?
 
090415-1654 EST

Shells:

You would be overloading the one phase of the transformer. Basically you have three transformers, each with a 3 KVA capability. You want to load phase P3 to 3600 + 120 = 3.720 KVA.

Describe your 3600 load and why it can not be split into smaller pieces?

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Shells said:
So I have a 9kVA, 480V, 3-phase 208-120V encapsulated transformer located outdoors. Currently each phase is barely loaded, P1-420W, P2-420W, P3-120W. I would like to add a 3600W load to this transformer since it is the nearest power source. The cost overuns would be significant if I would have to build scaffolding and run cables from a remote location. My concern then is the phase current imbalance. I would now have at best one phase being at least 8 x loaded that the other 2. There is no way I can adjust the loads to achieve current balance. Since the transformer would still be only about 50% loaded I am not sure if the heating effects will be significant. In the interest of cost, it is sufficient to say that I can add the load as planned, measure the phase current on installation and perform periodic infrared scans to detect any overheating. If overheating is observed, I can install a bigger transformer to handle the overheating. Any comments?
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I am assuming then that this 3600W is a single phase 120V load based on the fact that you said the one phase would be 8X the other phases.

Is there a way to change your load to a 208V or 240V voltage rating so that you could then split up the load on two of the phases?
 
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