AC COOLING FAN - SANYO DENKI EUROPE - #48

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Technical Material 47 Tightening Torque This shows the recommended values for the tightening torque when installing the fans. If the tightening torque is higher than the recommended values, the fan can be deformed or damaged. Use care when tightening. Recommended screw torques Fans : 0.44N�Em (4.5kgf�Ecm) MAX. (with M3 screws) Fans : 0.78N�Em (8kgf�Ecm) MAX. (with M4 screws) (160mm×160mm�Aö172mm) Handling precautions The fan motor is equipped with a precision ball bearing. Therefore, please handle the motors carefully in order not to shock the bearings. Installation There are no limitations on the installation direction. Fans have symbols on the fan indicating the airfl ow direction and blade rotation direction. When installing, use these symbols to check the airfl ow direction. Air Flow direction Symbols indicating the fan airflow direction and blade rotation direction Blade rotation direction Discharge side Suction side Cautions for use of a cooling fan in the vicinity of a power switching circuit (prevention of electrolytic corrosion) UPS, inverter, rectifi er, high-voltage power supply, etc. Storage temperature There is no performance problem when the system is used at between -30�Ž and +70�Ž . There is a possibility that same problem of lubricant and insulation inside motor might occur by condensing due to rapid surrounding temperature change. Therefore, please take care of non-condensing using desiccant or something during fan is in storage. Operating precautions Operating precautions If a fan is installed near a large-power or high-voltage switching circuit, the heavy electromagnetic noise resulting from electromagnetic induction in such circuits or the infl uence of high-frequency noise imposed through the power line of the fan may induce current through the shaft bearing of the fan.Such current may damage the oil fi lm on the bearing and even the friction surface of the bearing.This adverse effect is known as "electrolytic corrosion of the fan."Electrolytic corrosion affects the smooth revolution of the fan and may reduce its service life. An audible symptom is unusual noise emitted from the fan.This adverse effect is often observed and may partly be explained by the practice of mounting high-density parts, which reduces the gap between the switching circuits and the fan and the use of higher switching frequencies apt to provoke induction. Data processing/communications devices that operate at low voltages are not liable to electrolytic corrosion since they generate less electromagnetic noise. A Case of Electrolytic Corrosion Measures against Electrolytic Corrosion (1) Relocate fans far from all electromagnetic noise sources. (2) Use anti-corrosion fans equipped with ceramic bearings. Refer to page 38 (3) As a power supply, the fan is wired from a circuit for which noise is not superimposed. *The EMC guard could be effective against electromagnetic noise caused by radiation, but against heavy electromagnetic noise (electromagnetic induction) and conductive noise from the power supply line for a fan, we recommend the use of an "anti-electrolytic corrosion fan" with ceramic bearing. Fans without anti-corrosion features installed near components that generate electromagnetic noise, such as inverter controllers, are liable to experience electrolytic corrosion. The curve shown in the graph below represents the relationship between the level of the electromagnetic noise induced by a fan and the distance from the fan to the noise source. Range in which electrolytic corrosion is generated Level of noise induced by a fan Distance from the noise source to the fan Range in which electrolytic corrosion is not generated No. Use Period until the occurrence of unusual noise 1 Switching power supply 6 months to 2 years 2 UPS 6 months to 2 years 3 General-purpose inverter 1 to 1.5 years Custom Product Refer to page 38 (1)The fan gets charged with high-frequency electricity by high-frequency noise (electric fi eld/magnetic fi eld) generated in the switching circuit. (2)Because of high-frequency electricity charged in the fan, an electric current fl ows through the bearing of the fan. (3)The electric current breaks the oil membrane on the surface of the bearing and the bearing gets abraded (electrolytically corroded). (4)This symptom often occurs in equipment in which switching circuits are sped up and implemented in high density. (5)Countermeasure 1: To provide a shield plate (Note 1) inside the fan (The plate should be such that does not interfere with air fl ow.) (6)Countermeasure 2: To use a fan with ceramic bearings. (1)High-frequency electricity fl ows from the circuit board into the inside of the fan superimposed with the power line for the fan. (2)High-frequency electricity that has entered into the fan fl ows through the bearing. (3)Oil membrane on the surface of the bearing gets broken and the bearing gets abraded (electrolytically corroded). (4)Countermeasure 1: To remove high-frequency component between terminals "a" and "b", "a" and "e" and "b" and "e" of the power supply for the fan, or to insert a fi lter (Note 2) into the power line for the fan. (5)Countermeasure 2: To use a fan with ceramic bearings�@ (6)Cables should be twisted in order to decrease induction to the power line for the fan. Switching circuit board of the equipment Power supply for the fan Terminal b Circuit board grounding Fan cabinet Metal cabinet of the equipment Component parts of the switching circuit e Wind Terminal a Electric field/magnetic field of the high-frequency electricity Pattern 1 Shielding metal Pattern 2 Mounting screw High-frequency electricity is superimposed onto the power line for the fan. Return path of the high-frequency electricity Propeller �iGrounding to the cabinet�j Occurrence of electrolytic corrosion Pattern 1 Occurrence of electrolytic corrosion Pattern 2 Note 1�FShielding metal plate As an electromagnetic shield metal, "EMC Guard" is available from our company. Certain shielding effect can be expected from mounting a general-purpose fi nger guard inside the fan.In each case, grounding to the cabinet is required. Note2�FFilter Insert a common mode fi lter when the high-frequency electricity is superimposed on both lines "a" and "b" in the same phase and, if not, insert a normal mode fi lter. http://www.sanyodenki.co.jp/products/sanace/fanden.html