Fans started work bearing vibration small parts, but with longer centrifugal fan running time where, in the dust will be uneven fan attached to the impeller, the gradual destruction of the fan balancing, bearing vibration gradually increased, Once the fan vibration reaches the maximum allowed 11mm / s (with an amplitude value represents the maximum allowable value below), the fan must be shut down to repair (remove dust accumulation, redo balancing). Because this time is very dangerous, the user must not be forced to use. Fan vibration when approaching a dangerous level of the largest manufacturers of centrifugal fan, there will be vibration meter alarm. Axial fans at startup, the motor current will be higher than 5-6 times the rated centrifugal fan function, not only will affect the life of the motor and consume more power. System designed on the motor selection would have a certain margin, the speed of the motor is fixed, but in actual use, sometimes you want to run at a lower or higher speed, frequency transformation is therefore very necessary. Drive motor soft start can achieve by changing the frequency of the input voltage equipment to achieve the purpose of energy-saving speed, and give the device to provide overcurrent, overvoltage, overload protection. Where centrifugal fans _ Hao Yang air conditioning equipment (certified) _ centrifugal fan from the Texas Air Conditioning Equipment Co., Ltd. Hao Yang provided. Air Conditioning Equipment Co., Texas Hao Yang (www.dzhykt.com) is Dezhou, chemical fiber fabric, lining leaders, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. Hao Yang air conditioning equipment in leadership with the staff warmly welcome all inquiries negotiations to create Hao Yang air conditioning equipment a better future.