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Transformers

Control Transformers – STN

Moeller STN control transformers ensure reliable operational voltage for control and auxiliary circuits in power distribution and automation applications – total reliability all the time.

The right voltage

Control transformers enable machines and plants to be adapted to the wide range of supply voltages and supply networks found all over the world. Thanks to the standard additional tapping of ±5% of the primary voltage they increase the functional reliability of electrical control systems that are subject to constant overvoltages and undervoltages from the mains supply. In the event of a fault, control transformers reduce the level of the short-circuit current in the control circuit, and also allow the unearthed operation of the auxiliary current.

The STN transformers are designed to be used exclusively as control transformers. Transformers for the most common voltages are always kept in stock so that they are available at all times.

Control, Isolating and Safety Transformers – STI, STZ, DTI, DTZ and UTI

STI, STZ, DTI and DTZ control, isolating and safety isolating transformers are UL/CSA-approved and are thus suitable for use worldwide. The STI and STZ single-phase transformers and DTI and DTZ three-phase transformers are suitable for all applications which require increased control system safety.

Increased isolation

The isolating transformers are provided with reinforced isolation between the input and output windings. They are suitable for the "safe" isolation of electrical circuits in danger or hazardous areas with an electrically conductive environment.

Increased protection – everywhere

Safety isolating transformers offer a high degree of protection for use in harsh operating conditions such as with wet-grinding machines, cement vibrators, etc. These transformers are a special type of isolating transformer with a maximum secondary voltage of <50V.

One transformer in stock for all applications throughout the world

The UTI multi-winding transformer is the most universal product in the range. It, too, can be used as a control, isolating and safety isolating transformer and has UL and CSA approval. With its thirteen standard input voltages, the UTI is the ideal transformer to keep in stock for export. With only one actuating voltage for the entire control system, the UTI can be used for applications throughout the world.

Matching Transformers – ET and DT

The fact that there are many different voltages throughout the world often leads to high costs in the export business. With machines and installations that are designed for a certain voltage, many components often have to be replaced so that they can be used in a country with a different voltage.

Moeller offers ET single-phase transformers and DT three-phase transformers specifically for these situations. They are used to adapt machines and installations to different voltages and to establish galvanic separation between the power supply system and consumers. In this way, only the transformers need to be replaced and not the installation's devices.

Accessories increase functionality

A host of accessories are available to enhance the functionality of Moeller matching transformers:

• Special steel enclosures offer additional touch protection.
• IP 65 enclosures for applications requiring additional protection.
• Additional screening (screen winding) between the primary and secondary circuit.
• Special isolating coating, making transformers suitable for conditions with a high relative humidity.
• Inrush current limiters attached directly to the primary terminal reduce inrush current and make it easier to protect transformers against short-circuits.

Economy Transformers – ETSP and DTSP

Economy transformers are a special type of matching transformer. Moeller's product line includes the ETSP single-phase transformers and the DTSP three-phase transformers. In the case of economy transformers, the input winding and output winding are not isolated. Furthermore, the throughput rating of these transformers is always greater than their kVA rating. Using an economy transformer is the most cost-effective way of adapting to different voltages if no galvanic isolation is required.

Transformers in Medical Facilities – ET-MED and DT-MED

DIN VDE 0107 precisely specifies what types of transformers can be used in medical facilities. The ET-MED single-phase transformers and DT-MED three-phase transformers are built and tested according to this standard. The transformers are thus equipped with all necessary technical features, such as an eight-fold reduction in inrush current. The temperature monitoring specified by the standard is implemented with a bimetal temperature sensor. However, these safety transformers can also be equipped with other types of monitoring units.

Through the use of capacitors, the volume of medical transformers is kept to a minimum. These transformers are available as both single-phase and three-phase transformers for five rating classes.

Starting Transformers – DTA

Special transformers for special applications DTA starting transformers are a special type of economy transformer. Starting transformers are used as current limiters for starting three-phase induction motors, thus eliminating supply voltage dips, for example, with weak networks and larger motors.

Of course, Moeller can also produce customized transformers if the type of transformer a customer needs is not available in our catalogue. Regardless of whether a transformer is needed for lighting a runway or for a wind-power station, or whether a miniature transformer or a transformer for high output is required, Moeller applies its extensive technical expertise to achieve top-quality results.

This page last updated: 8 September 2001