Single Phasing effect on heater

[chunt550]

What is the effect of single phasing on a 480vac, 3 phase, delta connected heater, fed from a 480vac, wye connected source with a fused disconnect switch? Would the remaining two legs see an increase in current, and cause damage to the heater; or would it just lower the output of the heater?

Thanks

 

[Skogsgurra]

The element between live phases produces same heat as before i.e. 1/3 of total. The other two see half voltage each and thus produce 1/12 heat each. In all you will have 1/3 + 1/6 = 50 % of original heat. No overheating anywhere.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[alehman]

If the heater has a 3-phase fan, it would cause problems for the motor.

 

[itsmoked]

Unless full-ON for a while damages the heater element and due to loss of power the heaters remain ON essentially continually and the one receiving 1X power can't take it.

I have seen this but it is not a good design and hence not common.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com