RU84361U1 - REDUCED DOOR DOOR DRIVE - Google Patents

Abstract

 Gearless drive of the sliding door leafs containing the driving and driven pulleys connected by an endless flexible traction unit, which is connected to at least one door leaf and connected to the driving pulley by an asynchronous drive motor, the stator windings of which are connected to an alternating current main through a frequency converter, characterized the fact that the highest value of the frequency of the voltage at the output of the converter does not exceed the limit value of the frequency, below which no electric power is supplied from the induction motor ogy to the power source, and depending on the required maximum speed of the sashes drive pulley has a diameter defined by the expression! ! where Dш is the diameter of the drive pulley; ! p is the number of pole pairs of the induction motor; ! vm - maximum speed of movement of the valves; ! fп - the highest value of the frequency of the output voltage of the frequency converter.

Description

The proposed technical solution relates to hoisting-and-transport machines, mainly to elevator installations.

Known gearless drive doors of the elevator car (RF patent, class B66B 13/06, No. 2146644, 1995), containing an asynchronous motor connected by means of a frequency converter to an AC network. The disadvantage of this device is the use of a more expensive equipment frequency converter - a brake resistor and a controlled brake key.

The problem the proposed utility model is aimed at is creating a gearless variable-speed drive for sliding door shutters with a reduced cost.

The solution to this problem is achieved by the fact that in a gearless drive of the sliding door leafs containing the driving and driven pulleys connected by an endless flexible traction body, which is connected to at least one door leaf, and connected to the driving pulley by an asynchronous drive motor, the stator windings of which through a converter the frequencies are connected to the AC mains, the highest voltage frequency at the inverter output does not exceed the frequency limit value, below which from the asynchronous motor Atelier does not receive electricity to the power source, and depending on the required maximum speed of the leaves, the drive pulley has a diameter determined by the expression

where D _W - the diameter of the drive pulley;

p is the number of pole pairs of the induction motor;

v _m - maximum speed of movement of the valves;

f _p - the largest frequency value of the output voltage of the frequency Converter.

In addition, a disadvantage of the known device is the use of an induction motor made with the number of turns corresponding to the rated voltage and the rated frequency of the network, in the frequency range significantly less than the nominal. In this case, the frequency converter must be selected for the rated current of the specified motor and has a relatively high cost.

In the proposed utility model, the task is also to reduce the current to which the frequency converter is selected, which further reduces its cost and at the same time the cost of the entire drive.

The solution to this problem is achieved by the fact that in a gearless drive of the shutter of the shutter doors, the induction motor is made according to utility model No. 55224, in which the highest value of the lowered frequency is equal to the highest value of the voltage frequency at the converter output.

Figure 1 schematically shows the proposed gearless drive of the doors of the sliding doors, figure 2 shows a diagram of the electric drive.

The sliding door leaf drive comprises a leading 1 and a driven 2 pulleys connected by an endless flexible traction body 3, which is connected to at least one door leaf 4, and a drive induction motor 5 connected to the driving pulley.

The stator windings of the motor 5 are connected to the output of the frequency converter 6, the input of which is connected to the AC network 7. The Converter 6 is equipped with a control unit 8, with which you set the desired voltage and frequency at the output of the Converter.

Gearless drive of the leaves of sliding doors operates as follows. During operation of the engine 5, the driving pulley 1 rotates, which, through the thrust element 3 thrown through it, moves the door leaf 4.

In the process of operation of the electric drive, the highest value of the frequency f _{p of the} voltage at the converter output does not exceed the limit value of the frequency f _gr , below which no electric power is supplied from the induction motor to the power source. Indeed, from the expression for the active power P ₁ at the stator terminals of an induction motor

where U _f and I ₁ - the effective values of voltage and current for one phase of the stator of the motor; φ ₁ - the angle between the voltage and current vectors of the phase, follows:

if φ ₁ <90 °, then P ₁ > 0, i.e. an induction motor consumes electrical power from a power source; if φ ₁ > 90 °, then P ₁ <0, while the induction motor gives electric power to the power source. The angle φ _{1 is} determined by the ratio of inductive and active resistances included in the well-known T-shaped equivalent circuit of an induction motor. With decreasing frequency, the inductive resistances decrease, which also leads to a decrease in the angle φ ₁ .

At a certain low frequency, which can be called the boundary, the angle φ ₁ becomes less than 90 ° for any slip. Therefore, if the frequency of the stator voltage is lower than the boundary, which, as can be shown, is determined by the following relation

then under no slip from the induction motor does not receive electricity to the power source. In the last expression

R ₁ - the active resistance of the phase winding of the stator of the motor;

X` ₂ and X ₀ - included in the T-shaped equivalent circuit of an induction motor and the inductive resistance of rotor scattering and mutual induction corresponding to the rated frequency f _nom .

At a frequency f _{p, the} synchronous angular velocity of the induction motor is equal to ω _{s, p} = 2πf _p / P, while the translational speed of the valves is determined by the expression

substituting into which the diameter of the pulley according to the formula of the utility model in the form D _W = pv _m / πf _p , we obtain v _k = v _m , i.e. the sash speed is equal to the required maximum value.

Since at frequencies f _p <f _{gr the} induction motor does not give electricity to the power source, then under braking conditions there is no need to use a brake resistor and brake key in the frequency converter, which reduces the cost of the converter.

If an asynchronous motor in a direct drive of sliding door leaves is made according to utility model No. 55224, in which the highest value of the lowered frequency is equal to the highest value of the voltage frequency at the converter output, then the cost of the drive is significantly reduced. In fact, when performing the stator winding of an induction motor with an increased number of turns according to utility model No. 55224, the phase currents of the motor and the frequency converter are significantly reduced, which further reduces the cost of both the motor and the converter.

Using the proposed technical solution allows you to create gearless adjustable drives of the shutter doors, in particular, the elevator car, which at a relatively low cost are characterized by reliable and inexpensive operation.

Claims (1)

 Gearless drive of the sliding door leafs containing the driving and driven pulleys connected by an endless flexible traction unit, which is connected to at least one door leaf and connected to the driving pulley by an asynchronous drive motor, the stator windings of which are connected to an alternating current main through a frequency converter, characterized the fact that the highest value of the frequency of the voltage at the output of the converter does not exceed the limit value of the frequency, below which no electric power is supplied from the induction motor ogy to the power source, and depending on the required maximum velocity flaps drive pulley has a diameter defined by the expression

, where D _W - the diameter of the drive pulley; p is the number of pole pairs of the induction motor; v _m - maximum speed of movement of the valves; f _p - the largest frequency value of the output voltage of the frequency Converter.