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Synthetic resin insulated, indoor current transformer
for 0.72 kV and 1.2 kV highest voltage for equipment
Types AMt-0, AMt-1 with fixing base

Type marking

The letters and numerals applied in type markings have the following meanings:

A – current transformer
M – synthetic resin insulated
t – foot mounted design
0, 1– highest voltage for equipment 0.72 kV or 1.2 kV




General description

The synthetic resin insulated indoor current transformers, types AMt-0 and AMt-1 having a single core, are manufactured for rated primary currents from 5 to 1000 A and rated secondary currents 5 A or 1 A, for use in systems of highest voltage for equipment 0.72–1.2 kV.
The current transformers comply with the specifications of MSZ EN 60044-1 and EN 60044-1, but to order according to other standards, differing from these, is also possible. At the thermal and dynamic tests the phase distance is 130 mm.
The current transformers, manufactured in serial production, can be applied indoor under moderate climate conditions. On request it can be produced in finish suitable for tropical use too.
The material of the primary and secondary windings is cooper. The ends of the windings are connected, on the primary side to a flat bar or connecting shoes, on the secondary side to threaded blocks embedded in the synthetic resin body. The primary and secondary terminals are produced without surface protection. Upon agreement we deliver in finish for use under the requested climatic conditions, with plated terminals. The secondary terminals are placed on the top of the instrument and can be closed and sealed by means of a plastic cover.

Packing, delivery

The current transformer is delivered in a finish suitable for use under normal climatic conditions, packed in corrugated paper box, but upon agreement also in packing fit for marine or aerial transport.


In case of a long-term storage, it is practical, to keep the current transformer indoor, in a covered, well ventilated room (storage temperature: –5 °C, +40 °C).

Installation, putting into operation, operation

Before installation the current transformer should be checked in order to discover on the surface, or on the terminals any possible damages occurred during the transportation or the storage. In case of any damages further investigation is necessary.
The current transformer can be mounted in any position. When connecting the primary busbar, care should be taken in order that the end of the busbar does not near to the synthetic resin body less than 5 mm. The current transformer type AMt can be fastened by four M5 screws
Before connection, any contamination, occurred during the transportation and storage should be removed, the terminals cleaned and smeared with contact vaseline. The proper connection can be achieved paying attention to the markings on the primary (P1, P2) and on the secondary (S1, S2) side. For earthing, we propose one of the secondary terminals.
The operation is possible keeping the prescriptions of the relevant security-, labour- and property-protection directives. Any faults and breakdowns emerging in the customer’s sphere of interest due to breaching, disobeying the afore-mentioned, exempt the manufacturer from the warranty and guarantee liabilities.

The maintenance consists of works to be done according to the general rules for indoor instruments and discontinuing of the accidental irregularities. These are:

– periodical inspection of the contamination and cleaning, depending on the degree of impurity,
– inspection of the surfaces,
– tightening of the bolts of the primary and secondary connections,
– tightening of the fastening bolts.

State verification

The secondary windings of the current transformers in classes 0.2 and 0.5 are manufactured in finish suitable for verification. The verification will be made only on special request, in this case it will be accomplished and documented by an official seal or an affixed verification stamp, by the State Office for Measurement.

Data to be submitted with the order
– type (e.g. AMt-0),
– rated insulation level (e.g. 0.72/3/– kV),
– rated primary and secondary currents (e.g. 200/5 A),
– accuracy class, output and instrument security factor of the secondary winding. (e.g. class 0.5, 15 VA, Fs5),
– quantity,
– requested term of delivery.

Other or special requirements

– application of primary terminals differing from drawing,
– climatic zone of use other than normal,
– surface protection of primary terminals,
– language of the rating plate,
– packing,
– number of pieces and sort of the documentation to be attached.

Warranty period, guarantee

warranty period is 12 months and otherwise it can also be established upon the mutual agreement of the parties respectively.
All right reserved for subsequent alteration without prior notice.


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