Large and medium-sized squirrel-cage asynchronous motors are one of the main electrical equipment for many industrial and mining enterprises. According to the regulations of the National Energy Conservation Center, high-voltage motors should be preferred for large and medium-sized motors, and the starting of high-voltage motors is a primary issue. In various industrial and mining enterprises, high-power cage motors generally use direct starting, series reactor starting, high-voltage There are several starting methods, such as variable frequency soft start, series liquid resistance voltage reduction start, etc. The motor directly connected to the high-voltage power grid will cause the grid voltage to drop when starting at full voltage, affecting the normal operation of other equipment on the power grid, and even causing accidents; the motor connected to the special transformer requires a certain margin for the transformer capacity, and Most companies choose the transformer with limited capacity margin, and can only start at full voltage at no-load, and add load after starting, which will cause a great mechanical impact to the motor and greatly shorten the service life of the motor and the driving system. In these cases, we can only start the squirrel motor by means of reduced voltage starting. In view of this situation, our company has developed a liquid resistance soft starter suitable for large and medium-sized squirrel motors based on several years of experience in the development of liquid resistance products. This product makes full use of the characteristics of large heat capacity and good adjustability of liquid resistance, and can control the starting current of the motor within the range of 2-3.5Ie times the rated current of the motor, which greatly reduces the starting current. It has become the ideal soft starter product for international large and medium cage motors.Rated voltage (KV) 0.38, 3, 6, 10 Maximum voltage (KV) 0.415, 3.5, 6.9, 11.5 One minute power frequency withstand voltage (KV) 2, 25, 30/32, 38/42 (relatively) One minute power frequency withstand voltage (KV) 2, 25, 30/32, 38/42 (alternate) (The above pressure does not include the electro-hydraulic tank) Starting current (A) Iq: 1.5-3.5Ie Starting time (S) Ti: 10-60-120 (adjustable on site) The number of consecutive starts is more than 3-5 times Electrolyte normal working temperature rise (℃) ≤15℃/time Protective function: LQ series cage type motor liquid resistance starters are equipped with liquid resistance over-temperature, liquid level fault, transmission overload, starting overtime and over-travel, and action faults of various peripheral devices on the periphery. A complete protection program has been written in the PLC program (common type It also has these protection functions), and reserves a fixed external interface for the user. Thus, the soft start process can be completed safely and reliably by using the protective motor. Basic working principle: According to the motor drag theory, a liquid resistor configured with a special medium for dividing pressure and limiting current is connected in series in the stator circuit of the motor. During the starting process, the resistance value of the liquid resistor automatically changes from large to small within the set time. Stepless change, so that the terminal voltage applied to the motor stator is gradually increased, and the starting torque is gradually increased. When the motor speed is close to the rated speed, the liquid resistance is removed and put into full-voltage operation to realize the low-current stable soft start of the motor. Features: ◇Constant current soft start: the starting current is small, which is 2 to 3.5 times the rated current of the motor; ◇The starting process is smooth, without impact, and the voltage drop of the power grid is within 10%, which ensures the reliable and safe operation of the power grid, effectively protects the motor and transmission machinery, and prolongs the service life of the equipment; ◇It is not affected by grid voltage fluctuations and load changes, which can ensure a successful start once, and can start more than three times in a row, which is better than high-voltage thermal resistor starters; ◇Have perfect alarm prompt function and motor protection function; Conditions of Use: Ambient air temperature: (-40～+50)℃ Relative humidity: ≤85% Altitude: ≤2000m Installation site: no significant shaking and shock vibration; no corrosive gas and conductive dust; installation inclination less than 5°. Control power requirements: three-phase four-wire AC 380V/220V±5%, 50Hz, 10A