Wiring heaters on Y connections from a delta source
Wiring heaters on Y connections from a delta source
(OP)
Hi,
Could anyone help me understand why this is a 277V configuration across the heaters instead of 480V? The incoming power is 480V, delta - so no neutral, while the heaters are 277V, single phase. My guess is that you can get 277V from a 480V only between phase and neutral -which is not the case here since there's no neutral. I attached here a hand draw wiring with 2 heaters in parallel per phase and just one heater per phase.
Thanks all in advance!
Could anyone help me understand why this is a 277V configuration across the heaters instead of 480V? The incoming power is 480V, delta - so no neutral, while the heaters are 277V, single phase. My guess is that you can get 277V from a 480V only between phase and neutral -which is not the case here since there's no neutral. I attached here a hand draw wiring with 2 heaters in parallel per phase and just one heater per phase.
Thanks all in advance!






RE: Wiring heaters on Y connections from a delta source
RE: Wiring heaters on Y connections from a delta source
Thanks for the input but I'm confused about the length.
I understand the geometry part but why is the length of any relevance in this case?
RE: Wiring heaters on Y connections from a delta source
RE: Wiring heaters on Y connections from a delta source
but isn't phase A to phase B(For example) supposed to be 480V? Instead, it show as 277V and this is the part I don't understand.
RE: Wiring heaters on Y connections from a delta source
RE: Wiring heaters on Y connections from a delta source
So in this case then, why the drawing shows that the 277V heater (not 480V) can be used in this configuration?
RE: Wiring heaters on Y connections from a delta source
RE: Wiring heaters on Y connections from a delta source
With six elements, parallel pairs, if one element goes open, the voltage across the other two pairs will drop. The voltage across the element paired with the failed element will rise.
If an element becomes shorted, the voltage across the paired element will drop to zero. The voltage across the elements on the other phases will rise to 480 Volts.
I have encountered this floating neutral connection on approved industrial equipment. With elements submerged in thermally conductive liquid, the elements can often withstand over voltage without badly overheating.
Elements heating other solid or gaseous media with lower thermal conductivity may be more prone to failure when subject to over voltage.
Bill
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"Why not the best?"
Jimmy Carter
RE: Wiring heaters on Y connections from a delta source