| | | I Motor protection All 1 ph. motors are fitted with thermal contacts (TK) as standard. For some models they are wired in series with the motor windings on others there are wired to the terminal block. The majority of speed controllable 3 ph. motors (except explosion proof) have thermal contacts (TK) wired to the terminal block. Motors with thermal contacts wired to the terminal block must be connected to a motor protection unit (see accessories). The ports marked 'TK' have to be connected in accodance with the wiring diagram. If temperatures in the motor windings are too high (e.g. caused by bearing problems, obstructed impeller, inefficient cooling, too high air flow temperature, 2-phase connection) the thermal contact trips and the motor protection device isolates the fan from the supply. The fan must be restarted manually. If this happens frequently there is a fault in the system which must be remedied. This protection offers a full protection of the motor even if speed controlled. Most HELIOS 1 ph. and 3 ph. fans have built-in thermal contacts as standard (see fan data table). For other models they can be supplied as an extra. Motors with thermal contacts wired in series with the motor windings. The majority of HELIOS 1 ph. fans with smaller performances have thermal contacts wired in series with the motor windings (see fan data table). They trip if the motor temperature is too high and open the electrical circuit. After having cooling down the fan will restart automatically. If thermal contacts trip this indicates a fault (e.g. stiff running, obstructions, too high air flow temperatures) which must be removed before continuing operation. Motors with built in PTC thermistors (positive temperature coefficient) are used for higher performances where temperatures rise quickly (e.g. under difficult working conditions).To offer a full protection each winding should be fitted with a PTC thermistor (available at special order; as standard for explosion proof rectangular fans as well as Axial and mixed-flow fans VAR with large motor powers (see product page). The thermistors are temperature sensitive elements. If a certain temperature is exceeded the electrical resistance jumps up. The thermistors must be connected to a special circuit breaker (type MSA, see accessories). | | Motors without thermal protection should be protected by a conventional circuit breaker (MCB miniature circuit breaker or RCD residual current device), which is to be wired between fan and supply (each phase must be protected). This option does not offer protection against exceedingly high air flow temperatures, insufficient motor cooling or if the fan is speed controlled. For pole-switching motors each speed should be protected separately. Air flow temperatures The standard fan range is suitable for operation in ambients from -30 to at least +40 °C, or higher for a short period (except explosion proof fans). The maximum permanent temperature for each model is stated in the fan data table. Specials are available on request. Speed control Speed control causes an increase in motor temperature. The max. temperature figures stated in the fan data table should be reduced by 10 °C when using a speed controller. Flow medium The standard models are suitable for normally dirty, humid, slightly aggressive air. For differing operation conditions please consult Helios. Protection against accidental contact Some fans come with a protection guard to DIN VDE 0700 respectively EN 294. Depending on the installation, additional protection may be required. The installer is responsible to ensure that sufficient protection is given. All safety regulations must be followed and a protection against accidential contact to EN 294 guranteed. The contact with rotating parts must be avoided. Ensure that there are not any items near the intake which could be pulled into the fan (e.g. curtains etc.) Fans which are installed within a ducted system might not need further protection guards if the system provides the required protection. We emphasise that the installer is liable for accidents due to unsufficient safety measures. A large range of guards is available as accessories. Explosion proof fans For operation in potentially hazardous areas or to extract hazardous fumes the fans are | | supplied with approved explosion proof motors and terminal boxes to ATEX 100 a or VDE 24169. They come in protection class "e" (increased safety) or 'd' (flame proof) which means that the fan is designed to avoid excessive surface temperatures and sparks and therefore an explosion. The European Building Regulation approval to 94/9 EG confirms that the design fullfills VDE 0170/017 and EN 50014/50019 and are enclosed with each unit. The reaction time tE (cut off time) is stated on the certificate of the motors and must be observed when selecting the motor protection device (circuit breaker) which must conform to VDE 0165. The temperature class (T1...T4) of each fan is stated on the product page; please see motor plate for correct data. It defines the maximum allowed surface temperature of the fan within the explosive atmosphere. The material combinations of the fans are in accordance with VDMA paper 24169, Pt.1. All explosion proof fans classified Exe II are suitable for operation within zone I and II. Models with protection to IP 54 are also suitable for use in zone 21 (explosive dust). When connecting the fans, all relevant regulations must be observed. Speed control is only permitted for models with fitted PTC thermistors in combination with a motor protection unit MSA (accessory). Special voltages, frequencies, protection classes Ex d are available on request. IP ratings An IP rating describes the amount of protection against solid and liquid objects entering a motor and consits of two digits. The first digit describes the protection against solid objects, the second against liquids. The two most common classes for dust and liquids are described as follows: IP X4: Motor enclosure protected against the harmful ingress of splashing water IP X5: Motor enclosure protected against the harmful ingress of water, when water is sprayed against the motor (weatherproof). IP 4X: Motor enclosure protected against the harmful ingress of solid objects greater than 1.0 mm. IP 5X: Protected against the harmful ingres of dust. | | ■ Approvals Helios fans have a high quality standard and conform with national and international regulations. When correctly installed they comply with the machinery directive. Various products undergo a process of periodical testing by independent bodies like TÜV, VDE and the Forschungs- und Materialprüfungsanstalt des Landes Baden-Württemberg, Otto-Graf-Institut. All products carry at least one of the following harmonized approvals: | | |