The control systems of PE mills are all centralized in the control cabinet. All levels are interlocked with each other. The feeding is automatically controlled by the change of the current of the host to control the feeding amount. The starting sequence of each machine is carried out according to the operating procedures and regulations. In this control cabinet, except for the main engine, the analyzer and the feeder, the motors of the other machines are uniform and general AC asynchronous motors.
A1: Start-up control of the main engine and fan of the PE pulverizer: For the motor capacity greater than 30kW, use decompression to start, and if it is less than 30kW, use direct start. In the system, the main engine fans all use star-delta start.
A2: The control and automatic feeding of the vibrating feeder of the PE mill: the structure principle of the electromagnetic vibrating feeder of the PE mill. It hangs at the lower end of the silo and has a certain swimming gap to be in a free state. It must not be stuck or collided with other objects, so as to avoid noise during work.
(1) The vibrating screen is driven by a J speed regulating motor, which is controlled by the electromagnetic slip controller (ZLK-1 type) button on the control cabinet. The squirrel cage motor part of the start button runs first, and then closes the slip power switch and adjusts the speed knob. Make the vibrating screen reach the required rotational speed and the required fineness (powder particle size) to match, so that the particle size of the powder can be controlled.
(2) When the automatic feeding of the PE pulverizer starts, turn the master switch on the control cabinet door to the automatic position. Gradually increase the potentiometer R1 knob on the control box to make the current reach the rated and stable current. At the same time, adjust the current relay sliding arm according to the rated current of the host to change the relay operating current. When it rises, the normally closed contact will be disconnected, and the current will drop slightly. It is closed immediately when the mill is turned off, so that the pulverizer always maintains the best working state, without causing empty grinding or overloading, and ensuring the efficiency of the main machine pulverizer.
(3) The automatic feeding adjustment of the PE pulverizer is realized by the change of the main current. When the fan is running normally, the main motor will stop feeding when the current exceeds the rated current, and will automatically feed when the current drops. This is mainly through the action of the current relay to disconnect and connect the controllable voltage to achieve feeding and stopping. There are 2 coils in the DL-12/6 type overcurrent relay, and its operating current can be adjusted from 1.5 to 3 amps when connected in series. When the two-wire power is connected, its operating current can be adjusted from 3-6 amps. When the mill is working normally, the current transformer changes and the current locked on the current relay will not be greater than 3 amps. Therefore, the coils are connected in series.
(4) Power-on no-load test, increase the amplitude potentiometer R1 of the electric control box sliver from small to small, its amplitude should be between 1.8 and 2.0 mm, the current should be 1.2 amps, and whether the amplitude current is stable for more than a few hours of continuous operation; normal; Then open the silo gate for feeding, observe whether the feeding current is stable, and allow the amplitude to drop by 0.5 mm. If the amplitude current reaches the rated value and still does not meet the feeding capacity requirement, the vibrator is hoisted at an angle of 20° to make it meet the Feed quantity requirements.
(5) After the vibrating machine of the PE mill is installed, loosen the screws acting on the positioning forks (three up and down), tighten the nuts after loosening, open the back cover of the vibrator, and check the iron core and the armature The gap should be within 1.8 to 2.1 mm, and the two screens should be cleaned. The screws should be strong, and the cover should be installed and fixed at the end.