Hottest motor soft starter qb6

The power element (three-phase anti parallel thyristor) of qb-r2 wound motor speed control controller of motor soft starter qb

qb-r2 is connected in series in the motor stator circuit, and the resistor matching the motor power is connected in series in the motor rotor circuit. The control circuit changes the stator voltage of the motor by changing the conduction angle of the thyristor, so as to control the speed of the motor

1. Lifting

when the master controller is used to select a gear of lifting speed gear, the speed controller first connects the lifting contactor, then the brake is opened, and the motor starts. Through rotor frequency feedback and speed setting of the master controller, the system enters the closed-loop control state. If the master controller selects full speed gear, the motor will accelerate smoothly to full speed; If you return from the full speed gear to the slow speed gear, the motor speed will decrease rapidly, and it will automatically enter the closed-loop control state and stabilize at the set speed. Regardless of the rising speed, as long as the master controller returns to zero, the brake will immediately brake, and then the motor will be powered off

2. Heavy load descent

when the master controller selects a gear of the descent speed gear, the speed controller first connects the rising contactor, and then the brake opens. At this time, the reverse torque is provided to the motor, and the speed controller enters the closed-loop control state. When the master controller is in full speed down gear, the down contactor is connected and the motor speed drops at full speed. If you return to the slow gear from the full speed gear, the lower contactor will be released and the rising contactor will be connected. Under the action of the reverse torque, the motor will decelerate rapidly and enter the closed-loop control state again. No matter at what descent speed, once the master controller returns to zero, the controller will brake with reverse torque, and the motor speed will decrease rapidly. After reaching the static state, the brake will brake, and then the motor power supply will be cut off for details. If the reverse torque braking time exceeds 1s, regardless of whether the motor reaches a static state, the brake will be forced to brake

3. Light load drop

figure qb-r2 winding motor speed controller block diagram

qf - circuit breaker; KM1 - lifting contactor; Km2 - lowering contactor; KM3, 4 - rotor contactor; Km5 - Brake contactor; Ka high quality and low price - overload protection; QB - R2 - speed controller

scr1, 2 - thyristor; M - wound motor; Ya - brake; R1, 2, 3 - rotor resistance

light load drop is the same as heavy load drop. The speed controller first connects the rising contact. It is mainly committed to the R & D and manufacturing of various static tension and compression testing machines, electronic universal testing machines, hydraulic universal testing machines, zigzag testing machines, electro-hydraulic servo dynamic fatigue machines and special fatigue testing equipment, and applies a certain reverse torque to the motor. If the load is extremely light (such as empty hook), The speed controller will judge that the load is too light, release the rising contactor, and connect the falling contactor. At this time, the motor will fall in the state of regenerative power generation. When the speed exceeds the set value, the speed controller will automatically turn to the reverse torque state

4. Translation

when the master controller is in the left shift position, the speed control controller connects the left shift contactor, and the car body runs to the left at the speed set by the master controller; The master controller is in the right shift position, the right shift contactor is connected, and the vehicle body runs to the right at the speed set by the master controller. When the main has an audible and visual alarm device; Torque direction identification; Multiple peak holding; The power display and low power prompt make the speed controller operate at a certain speed under closed-loop control. When subjected to a certain resistance (such as bridge tilt), the controller still maintains the speed under closed-loop control. If the resistance disappears, the translation mechanism will be accelerated; When it exceeds 10% of the set speed, the reverse contactor is connected and the motor begins to decelerate. At this time, the reverse torque does not exceed the full load starting torque, so the motor gradually decelerates to the required speed. If the translation mechanism receives the forward thrust at this time, the reverse torque is used to maintain the speed. If the forward thrust disappears, the reverse contactor is released, the forward contactor is connected, and the translation mechanism operates normally. The motor speed must be higher than 10% of the set speed to produce reverse connection. Therefore, the set speed of the master controller from 30% to 20% or from 20% to 10% will not trigger the reverse contactor

figure schematic diagram of lifting mechanism

figure schematic diagram of translation mechanism