Safety Isolating transformer

 

The Council Directive 89/39/EEC of 12 June 1989 on the introduction of measures to encourage improvements in the safety and health of workers at work lays down general obligations for employers in Article 6 and within these obligations it defines general principles of the risk prevention.

The company EEIKA Brno, s.r.o. has developed a safety isolating transformer OTB 230 for assurance of the safety at work with electric hand tools and portable measuring instruments in “restrictive conducting locations” according to IEC 364-7-706 (DIN VDE 0100-706).

The restrictive conducting locations arelocations surrounded mostly by metal or conductive parts, inside of which a man probably touches them with a part of his body, but the contact interruption possibility is limited. We can assume according to IEC 364-4-41 that the limited contact of two parts can be realized, when the distance between the conducting parts is less than 2,25 m. In compliance with the mentioned regulations OTB 230 uses the principle of separated circuit supply for protection against electric shock in these locations.

OTB 230 incorporates an isolating transformer (EN 60742), the secondary windings of which are separated from the primary windings on the level of protective separation (230 V) and/or safety protective separation (12 V – 50 V AC SELV).

The situations defined in above-mentioned standards occur in many branches and human activities. The boiler liner repair, in the course of which a worker is direct inside of a metal surrounded location, is a demonstrative example. The similar situations can arise during the course of plate roof assembly and repair, at work in collectors, cable channels, metal tanks and also elsewhere in engineering, chemical or building industry – it means everywhere in locations with metallic materials.

The Safety isolating transformer OTB 230 enables a simultaneous connection of hand tools in common use fed by 230 V voltage - hand drills, cutters, hand saws - and  portable hand lamps fed by 24 V. It is formed for easy handling in the workplace and for simple transfer from place to place. The transformer is placed in a solid shock-proof box and it is provided with the handle and the wheels for travel.

The Safety isolating transformer OTB 230 is delivered in several power variants with accessories according to the customer needs.

Standard type data:

Supply: 230 V/50 Hz

Secondary voltage: S1 – 230 V, S2 – 24 V, S3 – 24 V

Rated power: 2800 VA, 80 VA, 80 VA

Weight: 50 kg

IP Code: IP 55

 

Types of OTB 230:

OTB 230/1,3

Enables to supply one lower and medium wattage hand tool (up to 1170 W).

• Supply - 230 V/50 Hz
• Rated current I – 5,6 A
• Secondary voltage S – 230 V
• Rated power S - 1300 VA
• Weight - 39 Kg
• Cover - IP 55

 

OTB 230/1,3bn

Enables to supply one lower and medium wattage hand tool (up to 1170 W), enables connection of lamps and other equipment fed by 24 V.

• Supply 230 V/50 Hz
• Rated current I – 9,9 A
• Secondary voltage S1 – 230 V
• Secondary voltage S2(bn) – 24 V
• Rated power S1 - 1300 VA
• Rated power S2(bn) - 100 VA
• Weight - 39 Kg
• Cover - IP 55

 

OTB 230/2,9

Enables to supply one heavy high wattage hand tool (up to 2610 W).

• Supply 230 V/50 Hz
• Rated current I – 12,6A
• Secondary voltage S1 – 230 V
• Rated power S1 - 2900 VA
• Weight - 50 Kg
• Cover - IP 55

 

OTB 230/2,9bn

Enables to supply one heavy high wattage hand tool (up to 2610 W), enables a connection of lamps and other equipment fed by 24 V.

Supply - 230 V/50 Hz

• Rated current I - 13,1 A
• Secondary voltage S1 – 230 V
• Secondary voltage S2(bn) – 24 V
• Rated power S1 - 2900 VA
• Rated power S2(bn) - 100 VA
• Weight - 50 Kg
• Cover - IP 55

 

OTB 230/2x1,3

Enables a simultaneous connection of two lower and medium wattage hand tools (each up to 1170 W).

• Supply - 230 V/50 Hz
• Rated current I – 11,3A
• Secondary voltage S1 – 230 V
• Secondary voltage S2 – 230 V
• Rated power S1 - 1300 VA
• Rated power S2 - 1300 VA
• Weight - 50 Kg
• Cover - IP 55

 

OTB 230/2x1,3bn

Enables a simultaneous connection of two lower and medium wattage hand tools (each up to 1170 W), enables a connection of lamps and other equipment fed by 24 V.

• Supply - 230 V/50 Hz
• Rated current I – 11,9A
• Secondary voltage S1 – 230 V
• Secondary voltage S2 – 230 V
• Secondary voltage S3(bn) – 24 V
• Rated power S1 - 1300 VA
• Rated power S2 - 1300 VA
• Rated power S3(bn) - 100 VA
• Weight - 50 Kg
• Cover – IP55

 

Used regulations:

IEC 364-4-41 – Electrical installations of buildings. Part 4: Protection for safety. Chapter 41: Protection against electric shock.

IEC 364-7-706 - Electrical installations of buildings. Part 7: Requirements for special installations or locations. Section 706: Restrictive conducting locations.

EN 61140 – Protection against electric shock – Common aspects for installation and equipment.

EN 60742 – Isolating transformers and safety isolating transformers – Requirements.

Basic term definitions:

Restrictive conducting location – a location consisting mostly of metal or conducting surrounding parts, inside of which a man probably touches the conducting surrounding parts with a part of his body, but the contact interruption possibility is limited.
Isolating transformer – a transformer with protective isolation between input and output voltage.