Energy-saving Principle Of Frequency Conversion Speed Energy-saving Device
1. Frequency conversion and energy saving
From fluid mechanics, it can be seen that P (power) = Q (flow) ╳ H (pressure), flow rate Q is proportional to the primary square of the rotation speed N, pressure H is proportional to the square square of the rotation speed N, and power P is proportional to the cubic square of the rotation speed N. If the efficiency of the water pump is constant, when the required flow rate decreases, the rotation speed N can decrease proportionally, and at this time, the shaft output power P is in a square relationship. That is, the relationship between the power consumption of the water pump motor and the rotation speed is approximately the same as the ratio. For example: a water pump motor has a power of 55KW. When the speed drops to 4/5 of the original speed, its power consumption is 28.16KW, saving 48.8% of electricity. When the speed drops to 1/2 of the original speed, its power consumption is 6.875KW, saving 87.5% of electricity.
2. Power factor compensation and energy saving
Reactive power not only increases the line loss and the heating of the equipment, but more importantly, the reduction of the power factor leads to the reduction of the active power of the power grid. A large amount of reactive power consumption in the line, the equipment is inefficient and wasteful. From the formula P=S╳COSФ, Q=S╳SINФ, where S-apparent power, P-active power, Q-reactive power, COSФ-power factor, it can be seen that the larger the COSФ, the greater the active power P. The power factor of the ordinary water pump motor is between 0.6-0.7. After using the frequency conversion speed regulation device, due to the effect of the internal filter capacitor of the inverter, COSФ≈1, thus reducing the reactive loss and increasing the active power of the power grid.
3. Soft start energy saving
Since the motor starts directly or Y/D starts, the starting current is equal to (4-7) times the rated current, which will cause serious impacts on the electromechanical equipment and the power supply grid, and will also have too high requirements for the grid capacity. The large current generated during startup and vibration will cause great damage to the baffle and valve, which is extremely unfavorable to the service life of the equipment and pipelines. After using the frequency converter energy-saving device, the soft start function of the inverter will make the starting current start from zero, and the maximum value will not exceed the rated current, which will reduce the impact on the power grid and the requirements for power supply capacity, and extend the service life of the equipment and valves. Saves the maintenance costs of equipment.
