Safe And Efficient Dc Electric Overhead Crane Motor The Choice Of Heat Capacity
The choice of motor is mainly refers to the choice of heat capacity, which includes the motor overload capacity check and heat calibration. The overload capacity check is the ability to verify the larger workload that may occur in a short period of time for the motor service provider, Safe And Efficient Dc Electric Overhead Crane Motor and the heat check is to verify that the temperature rise of the winding exceeds the specified permissible temperature rise after a period of time.
Hoisting mechanism motor, start inertia load is small, the required acceleration torque is very small, only full load stable running torque of 10% -20%, while the motor's average aerodynamic torque is usually the motor rated torque of 1.6-1.8 times, making Start time is short (about 1-2S or so). So the lifting mechanism of the motor in the course of running can be ignored start the process, that the motor is running in the S3 operating system.
For the double rope grab lifting mechanism and opening and closing mechanism, the general use of two sets of the same drive mechanism. In the grab closed after the lifting of the moment, all the load with a closed motor to bear. Support the motor due to unloading and speed increases, Safe And Efficient Dc Electric Overhead Crane Motor and finally catch up with the closed motor and bear together. So the two machines of the same size of the rated power of the single need to be greater than half of the required power, closed motor has a short time overload capacity. Specification provides that each machine motor static power value of 0.66 times the total power, Safe And Efficient Dc Electric Overhead Crane Motor is to consider the lifting moment of the load is not uniform.
In the operating mechanism, the running resistance caused by the full load stability of the static resistance torque than the motor's rated torque is much smaller. Start-up must overcome the inertia load caused by the movement quality and the rotational mass, and the required acceleration torque is large. Safe And Efficient Dc Electric Overhead Crane Motor The start-up time of the operating mechanism is longer than that of the lifting mechanism, usually 3-8S. The electric operation belongs to the intermittent cycle operation system including start.
The operating power (steady resistance power) of the operating mechanism is related to the total mass (M), speed, coefficient of friction, etc., and the inertia power is related to the total mass, speed and acceleration (acceleration time). The speed is usually based on the frequency of operation Work level), Safe And Efficient Dc Electric Overhead Crane Motor then the coefficient can be multiplied by more than 1 to the steady-state operating power multiplied by the coefficient factor K to reflect the inertia power and operating frequency on the motor heating effect, the coefficient is also proven.
When the body design to complete the motor after the primary election, the electrical design of the motor should be overload and heat calibration. The motor overload check criterion is that the maximum acceleration (starting) torque of the selected motor should not be less than the minimum acceleration torque required for the mechanism to accelerate. When the unit has some (single or single) motor operation or other special conditions, Safe And Efficient Dc Electric Overhead Crane Motor it is necessary to calculate the minimum acceleration torque value of the motor required under these special operating conditions. When constant frequency closed-loop vector (or DTC) control is used, constant torque control can be achieved at the base speed. The system can be done with the maximum constant torque acceleration, and the voltage regulator or other control system for the winding motor, Safe And Efficient Dc Electric Overhead Crane Motor the acceleration process is extended serrated characteristic line, so overload check, pay attention to the sawtooth root to the acceleration The relationship between the maximum load.