The smoothness of acceleration and slowing down the elevator can be increased by a decrease in the values of the rotational and inhibitory moments of the engine, but the duration of the transition processes increases and their dependence on the load in the cabin increases.
The winding of high speed is the main winding on which acceleration and movement at the established speed is carried out. The value of the rotational moment developed by the engine when working on this winding should be in the zone, the lower boundary of which is determined by the magnitude of the static moments of the load on its shaft, and the upper one is limited to the amount of permissible acceleration of the cabin, taking into account the alternating load. In addition, the mechanical characteristic should not have failures.
The slownment of the movement of the elevators is carried out by disconnecting from the network of the winding of high speed and connecting the winding of low speed, at which, in generator braking mode, a decrease in the speed of the elevator is reduced. To obtain the same accelerations when slowing down and during acceleration, the brake moments when braking on the winding of low speed should be close in size to the rotating moments on the winding of high speed. At the same time, it is necessary that the trigger moment of the engine when working on the winding of low speed is above the moment of static resistance on its shaft when touching the elevator, the value of which is high enough due to the low coefficient of the useful effect of the worm reducer at the beginning of the acceleration. To ensure the necessary acceleration of the elevator in the revision mode and after an emergency stop between the floors with a fully loaded cabin, the starting point in the engine mode on the low speed winding should be at least one and a half multiple of the nominal moment of the engine.
The size of the moment on the winding of low speed first braking should be at least 80% of the maximum moment in the braking mode. This allows you to reduce the path of slowdown when approaching the location of the stop point.
Comfortable indicators are slightly reduced, since when switching from a higher operating speed to a small brake moment is applied as if stepped due to its own operations of the devices of the automation circuit that produce a sequential shutdown of the winding of high speed and connecting the winding of low speed.
An increase in comfortable indicators of the elevator during slowing can be achieved with such a mechanical characteristic on the winding of low speed, in which the moment during braking reaches the maximum value when sliding minus 60-80%.
In this case, the form of mechanical characteristics will ensure a smooth change in acceleration when reaching the established speed of the approach to the stop point and, thereby, the value of the “jerk” will turn out to be slight.
Elevator drive engines must have minimal values of starting currents, since the bulk of the elevators is installed in residential buildings with a relatively weak electrical network.
With a decrease in the starting current, energy losses per cycle are reduced, since at a frequency of inclusions per hour over 150, the starting losses reach 60-70% of the total losses.
The engine of the main drive is one of the main sources of noise when operating elevators, which are installed in machine -owned buildings from buildings for various purposes, and therefore it is necessary to take measures to reduce the noise level in rooms located near the machine.
The norms of the permissible noise level for the elevator drive engines both in the established and transitional operating modes are established based on the maximum noise levels for elevator winches.
To satisfy increased requirements for vibration levels, the engine should be balanced so that the amplitude of the vibration in the elevator cabin does not exceed 5 μm.
Two -speed engines for mass elevators are produced with synchronous rotation frequencies of 1500/18 and power on the winding of high speed from z to 17.5 kW.
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