Siemens 4MA7 indoor support-type current transformer block-type design

Siemens 4MA7 indoor support-type current transformer block-type design,
Current transformers can be regarded as transformers operating in short circuit, which carry the full rated current on
the primary side. The devices on the secondary side are
series-connected. They can have several secondary windings
with mechanically separated cores of the same or different
characteristics. Thus, current transformers can be designed
e.g. with two measuring cores of different accuracy class, or
with measuring or protection cores with different accuracy
limit factors.
Due to the risk of overvoltages, current transformers must
not be operated with open secondary terminals, but only in
short circuit or with the burden of the measuring equipment.