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Synthetic resin insulated, outdoor
Current transformer
For 12 kV and 24 kV highest voltage for equipment.




Type marking

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

A – current transformer
M – synthetic resin insulated
S – for outdoor use
24 – highest voltage for equipment

General description

The current transformers type AMS-24, – originally developed to operate remote controlled pole-mounted switches – is a synthetic resin insulated instrument transformer designed for outdoor operation in systems of highest voltage for equipment 12–24 kV.
The technical characteristics were determined so, that they are suitable to comply with both the demands of high accuracy measurements and – as a current sensing element of the system automatization – the high level fulfillment of the costumers’ demands, even is contaminated environment.
The current transformer with ring shaped iron core of cold rolled electrical steel, is made exclusively in single core design. The primary terminals are flat, cooper bars and the secondary connection is carried out with silicone insulated cable of 1, 1.5 and 2.5 sqmm2 respectively. Applicable for every – at present being in circulation – type of pole-mounted switch.
The current transformer complies with the specifications of MSZ EN 60044-1 and EN 60044-1 standards respectively.

Packing, delivery

The current transformer is delivered in a finish suitable for use under normal climatic conditions, packed in corrugated paper box. The secondary cable is provided with cable shoes or jointing sleeves and the primary terminals are made without plating. Upon agreement, we deliver in finish suitable for use under the requested climatic zone with plated terminals, and in the requested packing.

In case of a long-term storage, it is practical, to keep the current transformer in a covered, well ventilated place.

Installation, putting into operation, operation

Before installation the current transformer should be checked in order to discover on the surface, or on the terminals, inclusive of the secondary connecting cable, any possible damages occurred during the transportation or the storage. In case of any damages further investigation is necessary.
Generally the current transformer should be mounted in upright position, with horizontally levelled primary terminals. For the fastening to the supporting structure, the M16 bolt on the bottom of the device is intended.
Before connection, any contamination, occurred during the transportation and storage should be removed, the terminals cleaned and smeared with weatherproof 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.
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 outdoor 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 class 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. AMS-24),
– rated insulation level (e.g. 24/50/125 kV),
– rated primary and secondary currents (e.g. 150/5 A),
– accuracy class, output and instrument security factor of the secondary windings. (e.g. class 0.5, 2.5 VA, Fs10),
– quantity,
– requested term of delivery.

Other or special requirements:

– execution of the primary terminals (one or two borings)
– climatic zone of use other than normal,
– surface protection (plating) of primary terminals,
– length of the secondary connecting cable,
– execution of the end of the secondary connecting cable,
– language of the rating plate,
– packing,
– number of pieces and sort of the documentation to be attached.

Warranty period, guarantee

The 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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