Page 121 - Louth Transformer Catalogue

LT DATA

TRANSFORMER CONNECTIONS - Single Phase Types

Transformers with 2 primary windings are usually meant to be connected in either series or parallel, depending on
the supply voltage being used for example, a common primary found would be 0 - 120v, 0 - 120v, for 240v operation
the windings must be connected in series, for 120v the windings must be connected in parallel, never be tempted
to use only one primary, as this could seriously affect the operation of the transformer and could cause overheating.

Secondaries may also be wired in series or parallel but only if their voltages are the same and have been designed
for the purpose

TRANSFORMER CONNECTIONS - Three Phase Types

Three phase transformer connections are more complex than single phase transformers, there are also many more
different winding configurations. The most common two types being delta and star.

Input and output windings can be either star or delta (or other) types. Depending upon customer requirements.
In delta there are only three connections to be made. In star an extra terminal may be provided, called a star point
or SP. If this winding is the output winding the star point may be used to supply a voltage √3 smaller than the line
voltage.

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