About two-speed motor; two-speed motor is an asynchronous motor pole-changing speed is reached to change the number of pole pairs of the stator rotating magnetic field of the stator winding is connected by changing the method, thus changing the motor speed. According to the formula; n1 = 60f / p known asynchronous motor synchronous speed and inversely proportional to the number of pole pairs, doubling the number of pole pairs, exhaust fan manufacturers, synchronous speed down to half speed n1, the motor rated speed n will also fall approximately half of the high-temperature exhaust fan, so changing the number of pole pairs can achieve the purpose of changing the motor speed. This level of speed control method is not smooth speed control, and only applies to squirrel cage motors. HTF series exhaust fan fire for high-rise buildings, underground buildings and tunnels, drying room and other high-temperature exhaust or ventilation. Continuous operation at 280 ℃ under the high temperature for 30 minutes or more, the medium temperature at 100 ℃ continuous operation 20 hours / time is not damaged, exhaust fan quotes, fire is the ideal necessary facilities. 1, the performance of the fan performance table lists the performance, Heze exhaust fan in the most efficient range, according to the performance of the air volume is divided into five working points, according to prevail in the selection of the performance table. Qualified fan factory is rated flow, total pressure error does not exceed ± 5%, the performance of the selection list is performance under standard conditions, regardless of the technical documentation or performance are subject to the requirements of the standard state orders; 2, the fan installation can be divided into horizontal and roof type, air volume, total pressure, dimensions and other properties have special requirements; HTF series of high-temperature exhaust fan fire Overview: HTF series fire temperature exhaust fan with excellent performance, high temperature good performance, high efficiency, covering less than the centrifugal fan, easy installation. HTF series fire temperature exhaust fan of "national fixed fire extinguishing systems and fire-resistant component quality inspection center" test qualified, the performance of the leading domestic level. High temperature performance: Fan Test conform GBJ45-82 Fire Code standards, established above the standards of corporate internal control assurance system to run more than 60 minutes continuously under high temperature 300 ℃ conditions, at a temperature of 100 ℃ for 20 hours / time does not damage, widely used in senior civil oven, underground garage, tunnels and other occasions. Heze exhaust fan, Chen Yu air conditioning, exhaust fan quotes provided by Wu Cheng Chen-yu air-conditioning Limited. Heze exhaust fan, Chen Yu air conditioning, exhaust fan offer is wucheng Chenyu Air Conditioning Equipment Co., Ltd. (www.wccykt.com) this year introduced a new upgrade, the above picture is for reference only, please call or pictures on this page contact telephone number, to obtain the latest information, contact: sand manager.