4AM../4AT../4BT.. SIDAC-T transformers

Each situation requires a suitable transformer to ensure the right voltage.

SIDAC-T transformers are the right choice for each application: They are reliable and safe under different conditions worldwide.

• 4AM and 4AT special transformers: As a user-friendly bundle with isolating, control, and mains transformers to EN 61558-2-4, -2-2, -2-1 or safety, control, and mains transformers to EN 61558-2-6, -2-2, -2-1 or autotransformers to EN 61558-2-13 with selectable input and output voltages.
• 4BT special transformers: Single-phase power transformers as matching, auto or converter transformers in accordance with DIN VDE 0532-6 with selectable input and output voltages.

Note: SITAS mains transformers with ≤ 50 V on the output side are always supplied as safety transformers.

SIDAC-T transformers offer optimal protection with high permissible ambient air temperatures of up to 40 °C or 55 °C, high short-time rating for control transformers, fuseless construction, and the "Safety inside“ safety standard EN 61558.

Особенности

• High short-time rating for SITAS transformers: Lower rated transformer output for large number of contactors.
• PC program ASIST as design tool: Fast and optimal selection of correct control transformer
• Suitable for "fuseless construction": The low inrush allows the use of "circuit-breakers for motor protection" on the line side.
• UL approvals for the US and Canada: can be used worldwide without any problems
• Comprehensive range of different types can be supplied from stock: available immediately.

Область применения

For industrial machines, process engineering, heating and air-conditioning etc. and for supplying control and signaling circuits if

• Several electromagnetic consumers (e.g. contactors) are to be controlled
• Control and signaling devices are used outside the control cabinet
• The operating voltage which is required for the consumers is different to the one available.
• Voltage conversion for machines and plants with electrical isolation or as autotransformers.
• In drive engineering: Converter transformers for voltage conversion and autotransformers for use in infeed/feedback modules.

Generally for converting voltages for electrical devices e.g. for communications technology, medical apparatus, and domestic appliances.

The 4BT single-phase power transformers are used for plant, switching, and control technology as well as for converting the local mains voltage to the operating voltage of the plant or its components. In addition, they limit the possible short-circuit currents.

Power transformers with electrical isolation or autotransformers are used to convert the existing local voltages for machines and plants.

In addition, power transformers can be used for electrical devices used for communications technology, medical apparatus, and domestic appliances. Special converter transformers are used in drive engineering for voltage conversion and autotransformers are used for infeed/feedback modules.

Дизайн [PDF]

Дизайн

Regulations

EN 61558-2-6, -2-4, -2-2, -2-1, -2-13, DIN VDE 0532-6

The German standard DIN EN 61558 with the VDE classification VDE 0570 is the German edition of the international standard IEC 61558 (Safety of power transformers, power supply units and similar) and has fully replaced the previous standards VDE 0550 and VDE 0551.

Some transformers are subjected to more stringent manufacturing and testing conditions in view of these changes.

Transformers for general applications always have double or strengthened isolations for SELV voltages (exposed conductive parts, maximum AC 50 V or DC 120 V) i.e. these transformers are exclusively safety transformers.

In addition, all transformers have been marked with information about safety elements which can be used to protect them against short-circuits and overloads.

The SITAS transformer series includes the combined characteristics of safety, isolating, and control or mains transformers i.e. the transformers are suitable for (virtually) all applications. SITAS transformers fulfill the highest requirements (and with regard to safety the most stringent requirements) of the transformer designs contained in this catalog A SITAS transformer is always the right choice for all applications.

Rated power P_n for high ambient air temperatures – the characteristic for thermal capacity rating

Reference conditions used under which the transformers can be subjected to the rated power P_n listed in the selection tables:

• Continuous operation P_n
• Frequency AC 50 Hz ... 60 Hz
• Degree of protection IP00
• Site altitude up to 1000 m above sea level and
• Ambient temperature t_a, type dependent 40 °C or 55 °C.

Other installation and operating conditions than this will affect the permissible continuous load capacity. If the ambient temperature is 30 °C, the 4AM transformers, for example, can operate with 8 % more load. (see load characteristic).

Short-time rating Pn_(S6) of control transformers – the characteristic variable for the dynamic capacity

The most important selection criterion for control transformers is the short-time rating P_n(S6) . It is required for switching on electromagnetic loads e.g. contactors with high making currents in relation to the holding current. According to EN 61558-2-2 "Special requirements for control transformers“ the output voltage with this load should not drop more than 5 % in relation to the rated voltage in order to ensure safe switching.

Depending on their application, 4AM, 4AT control transformers ≤ 16 kVA are optimized for high short-time ratings with comparatively low ratings and thus small size.

Low inrush current – primary side short-circuit and overload protection with standard circuit-breakers

The 4AM and 4AT single-phase transformers for the power range ≤ 16 kVA have been designed for protective devices which provide reliable protection against short-circuits or overloads.

Standard 3RV and 3VF circuit-breakers offer optimum protection. In this way, the transformers are protected on the primary side against both short-circuits and overload, without the possibility of nuisance tripping on startup. The low inrush current, the short-circuit current, and the thermal load capacity on overload are matched to the tripping characteristics of the circuit-breakers.

It is also possible to protect the transformers on the secondary side against short-circuits or overloads with circuit-breakers or miniature circuit-breakers with C characteristics.

Note: The specified primary side circuit-breakers are for protecting the primary side of transformers in the event of short-circuits and overload on the secondary side. In the event of a possible short-circuit on the feeder lines between the protective device and the primary side of the transformer, the rated short-circuit breaking capacity of the circuit-breaker must be taken into account with regard to the maximum possible prospective short-circuit current at the place of installation. For device assignments, see table in the "Technical data".

ASIST design tool

PC program for selecting SIDAC-T control transformers in German, English, and Danish.

Дополнительную информацию Вы можете получить в Интернете по адресу.

http://www.siemens.de/sidac

The latest version of ASIST can be downloaded from „Support – Tools & Downloads – Design tool ASIST“.

EN 61558-2-2 only requires that the short-time rating is stated on the rating plate for a power factor = 0.5 of the load. The short-time rating of control transformers essentially depends on the power factor of the load. This increases particularly with smaller power factors. It is therefore even more important to calculate the short-time rating and the corresponding power factor accurately. The ASIST PC program has been developed as a design tool to minimize the time required to calculate the necessary type size, and ensures that the most suitable control transformer is selected in terms of engineering and price (see also "Technical data“).

Design

Standard design

All 4AM, 4AT and 4BT transformers are supplied for screw mounting on a mounting plate (exception: 4AM32 to 4AM40 are supplied as standard for screw mounting or with an integrated rail mounting).

Rail mounting

All horizontally mounted 4AM single-phase transformers from 25 VA to 500 VA offer a considerable saving in mounting requirements with snap-on mounting for the 35 mm rail mounting. For the single-phase transformers 4AM from 63 VA to 250 VA, the snap-on mounting for the 35 mm rail mounting has been integrated into the mounting plate of the transformer.

• Integrated design
  The 4AM32, 4AM34, 4AM38, and 4AM40 SITAS single-phase transformers are supplied as standard for screw mounting as well as with an integrated snap-on mounting for the 35 mm rail mounting in accordance with EN 50022.
• Optional design
  The 4AM23, 4AM26, 4AM43, 4AM46, and 4AM48 types of the SITAS single-phase transformers can be supplied with a preassembled adapter for mounting on a 35 mm rail mounting.

Connections

Screw-type connection

The 4AM transformers are supplied for rated currents up to 60 A, the 4AT transformers for rated currents up to 43 A, and the 4BT transformers for rated currents up to 81 A in the standard design with screw-type terminals.

For higher currents, the transformers are supplied with flat-type terminals or threaded pins.

Cage clamp connection

A large number of the SITAS 4AM single-phase transformers can be supplied on request with screwless cage clamp terminals (no multi-voltage design possible). The earth connection is designed as a Cage Clamp terminal.

Enclosure mounting

All 4AM and 4AT SIDAC-T transformers can be supplied on request in protective enclosures to degree of protection IP23 and IP54, the 4BT transformers can be supplied on request in protective enclosures to degree of protection IP20 and IP23.

Required specifications for requests and orders for 4AM, 4AT and 4BT special transformers

Rated power P_n (power separation for separate SEC coils, P_n = P₁ + P₂, throughput rating = consumer load for autotransformers), PRI and SEC voltages, frequency, vector arrangement, degree of protection (derating for other degrees of protection as IP00), stem Order No.

The Order No. stem is added to the Order No. for the delivery.

Ordering example / selection guide:

Special single-phase transformer 0.16 kVA

PRI 415 V ± 5%, SEC 115 V,

Frequency AC 50 Hz...60 Hz,

Degree of protection IP00,

Shield winding,

Order No. stem 4AM38 4

4AM and 4BT autotransformers: Determining the type rating P_{n typ.}

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Thermistor transformer protection for 4BT special transformers

The windings of the thermistor transformers can be protected from impermissible overheating by means of thermistor transformer protection. Thermistors are used as temperature sensors. These are embedded in the windings at each limb of the transformer and connected in series. The rated response temperature is slightly above the limit temperature for continuous operation and in the event of a short-circuit.

Possible designs:

• Warning
• Disconnection
• Warning and disconnection.

The connections of the temperature sensors are connected to terminals, 2 terminals each for warning and disconnection.

The 3RN tripping unit is not included with the transformer, for selection and ordering data see "Timer, monitoring, and coupling relays and SIMIREL converters; Monitoring relay; Thermistor motor protection“.

Технические данные [PDF]

Технические данные

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Характеристика

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