Jun 25, 2019
Fan category load is a general equipment needed in large quantity and wide range. At present, AC motor soft start drive scheme is widely used in fans such as kiln blower, raw material mill, cement mill, Raymond mill, explosion blower, central air conditioning return blower, blower, dust removal blower of various workshops and processes, automobile spraying system blower, all kinds of heating furnace and soaking furnace blower, industrial boiler blower, induced draft fan, natural gas purification plant recovery unit blower, fertilizer plant. Roots blower and so on.
Some of the large inertia centrifugal fans will reach the inrush current of 7 times the rated current when starting directly, which will cause circuit breaker tripping, shorten the service life of the motor and affect the safety of the power grid. When starting SSR, the thyristor conduction angle is controlled by an internal algorithm, so that the output voltage rises gradually from the initial set voltage to the rated voltage. Reasonable parameter setting can limit the starting current to less than 4 times. It saves the maintenance cost of the manufacturer and the investment cost of equipping circuit breaker and transformer and other related equipment. When starting directly, if the distance between the power box and the equipment is relatively long, there will be a large pressure drop, which will lead to the failure of fan starting. After being equipped with SSR soft start, the negative effect of pressure drop will be greatly lessened, which will help the fan start normally.