Jib lifting mechanism motor selection and description1, jib
crane motor requirements characteristics: repeated short-time operation, frequent, braking and reverse, often overloaded, with strong mechanical vibrations and shocks, dusty work environment, and have the added metal dust, and so on. For meet crane of work requirements, crane electricity motivation and general industrial electricity motivation compared has following features: (1) crane with motor by intermittent periodic work type manufacturing, usually with load continued rate (received electric continued rate), and received electric times and lifting times 3 a parameter expressed crane electrical equipment of intermittent cycle work business status, and as selection of important according to; (2) crane with motor has high of up moving turned moment and maximum turned moment (that overload capacity); (3) Has a lower moment of inertia of the rotor of hoist motor rotor of large length-diameter ratio; 4) reuse multiples of the maximum safe speed exceeds the rated speed of the motor is high, typically synchronous speed of 2. 5 times, (5) crane motor with 2 or more insulation classes are used at different ambient temperatures.
for jib cranes using a dedicated DC and AC motors. Main advantage is speed of DC motor range, overload capacity strong, smooth tone caught properties and larger starting, braking torque. Working voltage of 220 v and 440 v. But equipment costs high, the volume is large and requires a dedicated power supply, such as weakness, a small number of metallurgical cranes and smooth speed requirements in a wide range of drive mechanism using DC motors. AC motor, the main advantage of simple structure and power supply. Crane, three-phase AC induction motor with conical rotor motor is generally used, the working voltage of 220 v/380 v and 500V. Three-phase AC induction motors into JzR2, JZ2, and YZ Yz and the YZR, and ~ZR2, JZ2. Wound rotor induction motors using the most. Because this can add-ins starting resistance of the rotor of the motor circuit realization starting speed, smooth start, starting current does not exceed the rated current of 2-2. 5 times, and have a high overload capacity. Lifting machinery, in particular its lifting mechanism, often use this motor. Cage-type induction motor has the advantage of simple structure and manipulate frame the use of wound-rotor induction motor, disc brake motor.
3, jib lifting mechanism motor
lifting mechanism chosen is lifting machinery in the main and the most basic institutions. Lifting motor operation are: lifting small inertia loads, the accelerating torque required is very small, only full and stable operation of the torque of 10% or 20%, and the average starting torque of the motor usually the rated torque of 1. 6~1. 8 times, starting time shorter. Intermittent periodic duty--S3 duty motor operation. In lifting mechanical design in the, motor of select is a items important of content, motor of select main refers to motor of insulation grade, and rated power, and rated voltage, and rated speed, and type and the type type, and protection grade, and system, and adjustable speed way, and received electric continued rate, project of select, and which most important of is motor of insulation grade, and system, and protection grade of select and motor of power calculation.
4, insulation class power runtime, due to loss of heat, the motor temperature. Motor of the highest allowed temperature is heat-resistant insulation materials used by electric motors decided, degree of heat insulating material known as insulation levels. Different insulation material, its top border plus ℃ calculations. At present, the production of the motor using the e-class and b-class insulation, trend is to use differs from the f and h temperature allowed is, commonly used insulation materials are divided into 5 levels of insulation of the motor, so to some of the power output, reduce motor rating, including maximum allowable temperature rise of ring weight, reduced motor size.