SHELL and CORE Type Transformer

http://wiki.answers.com/Q/Difference_between_core_type_and_shell_type_transformer

Check this please

Transformer Types

check this please

Transformer Types

Shell/Core issue seems well covered by replies.

Key specification would be IEC76 or equivalent ANSI or national specification.

Transformer suppliers will tell you which of these specs they supply.

It is essential you know and tell supplier....

1. The required primary voltage supply nominal and variation from nominal.
2. Required rated maximum secondary load in kVA and any overload size and duration e.g. motor start
3. Secondary nominal voltage and variations permitted under steady and starting conditions. Type of loads supplied.
4. Number of phases and secondary connection required - e.g. 4 wire 3 phase with neutral.
5. Ambient temperature conditions,climate and location indoor or outdoor (weather protected or not).
6. Type of connection e.g. cable (plastic/bare/paper??) or busbar/rod. Single or multicore. Terminal or bolted - you give no clue to required rating/voltage and a control engineers "power transfo" is different to a Grid engineers "power transfo".
7. Dry or oil filled type - importance of fire risk.

Wikipedia has what seems to be a good article.

http://en.wikipedia.org/wiki/Transformer#Cores

Core form and shell form transformers

Core form = core type; shell form = shell type

Closed-core transformers are constructed in 'core form' or 'shell form'. When windings surround the core, the transformer is core form; when windings are surrounded by the core, the transformer is shell form. Shell form design may be more prevalent than core form design for distribution transformer applications due to the relative ease in stacking the core around winding coils.^[15] Core form design tends to, as a general rule, be more economical, and therefore more prevalent, than shell form design for high voltage power transformer applications at the lower end of their voltage and power rating ranges (less than or equal to, nominally, 230 kV or 75 MVA). At higher voltage and power ratings, shell form transformers tend to be more prevalent.^{[15][18][64][65]} Shell form design tends to be preferred for extra high voltage and higher MVA applications because, though more labor intensive to manufacture, shell form transformers are characterized as having inherently better kVA-to-weight ratio, better short-circuit strength characteristics and higher immunity to transit damage.^[65]