DE2348880A1 - AUTOMATIC WASHING MACHINE - Google Patents

Description

The invention relates to an automatic washing machine drive with a controllable semiconductor circuit arrangement a single-phase network fed, speed-controllable series-wound commutator motor.

Such drives usually contain in addition to the actual Drive motor for setting the speed provided in each case, a power unit that depends on several Setpoints are controlled by a speed controller in such a way that one or more changes in the motor current Allow the washing drum to reach working speeds in washing and / or spinning mode.

The object of the present invention is to drive a washing machine drive of the type mentioned above, the transition period from a higher to a lower one with the simplest means Reduce the operating speed and especially in the case of a spin operation with several successive start-ups To be able to shorten the time between the end of a spin cycle and the standstill of the washing drum.

The solution to this problem is possible according to the invention by that when changing from a higher to a lower operating speed with otherwise unchanged circuit the Armature winding of the series commutator motor is short-circuit closable. In the simplest way, only a single pole is used for this Short circuiter provided between the outer terminals of the armature winding.

- 2 -

5098U / 0608

- 2 - VPA 73/3277

Advantageously, it is provided that in braking operation with a short-circuited armature winding, the excitation current via the existing controllable semiconductor circuit arrangement in the sense of a specific braking torque curve control and / or is adjustable. Since the excitation winding is also in braking operation via the controllable semiconductor circuit arrangement that is present is connected to the single-phase alternating current source, is an influence on the braking torque - in contrast, for example to a resistance braking with the armature and field winding separated from the mains and then necessary, additional and complex power control stage to influence a then flowing excitation direct current - with the actually existing, intended for speed control in motor operation and because of their connection to an alternating current supply voltage simple circuit arrangement possible in the simplest way.

If the excitation current is changed as a function of the speed in the sense of a braking torque that increases with decreasing engine speed, this advantageously results in an optimal design of the braking torque curve, taking into account the torque characteristics the expiring one, due to the drum friction braked washing drum can be achieved »by the fact that it decreases sharply with decreasing speed, caused by friction losses Braking torque through a correspondingly increased braking torque of the series commutator motor short-circuited with its armature winding is compensated. Appropriately, a largely constant over the entire speed range Braking torque is regulated on the washing drum, taking into account the mechanical strength of the Suspension and transmission means of the drive device ensures the shortest possible run-out time. Another is an expedient embodiment of the invention, in particular with regard to the lowest possible expenditure on equipment characterized in that the excitation current can be controlled and / or regulated according to a predetermined time function. Appropriate For the time function, the desired,

5098U / 0608

VPA 73/3277

Average run-out time in the sense of the shortest possible, taking into account the structural data of the washing device Braking time required excitation current of the series commutator motor working in braking mode with a short-circuited armature winding set.

A particularly favorable one that fulfills the technological requirements of the intended washing machine drive. Braking characteristic can also be achieved in that the excitation current via the controllable semiconductor device during braking in the The meaning of a constant armature current during braking is specified.

The invention and further advantageous refinements are described below using an exemplary embodiment in FIG Drawing explained in more detail.

It shows in a schematic representation:

Figure 1 shows the circuit structure of the inventive washing machine drive

Figure 2 shows the torque curve M = f (n) solely due to the drum friction (a) as well as due to the additional through the drive motor with short-circuited armature winding (b) braked washing drum with regulation at constant Armature current.

Figure 1 shows a in-line commutator motor connected to the terminals R, Mp of a single-phase alternating voltage system via a controllable semiconductor arrangement 1 (triac) in a voltage supply line, with armature winding 2 and excitation winding 3 in series in so-called motor operation, i.e. with armature winding 2 not short-circuited Between the outer connection terminals 21, 22 of the armature winding and the commutator connections 23, 24 there is a reversing switch S ₁ , which is provided in particular for the periodic reversal of the direction of rotation of the washing drum during washing operation.

509814/0608 - 4 -

·· '■ · - 4 -. 'VPA 73/3277

According to the invention, a simple single-pole short-circuiter S _{2 is} provided between the outer connecting terminals 21, 22 of the armature winding, which can be closed in braking mode, so that the armature winding 2 is bridged and the excitation winding 3 continues to be supplied via the controllable semiconductor circuit arrangement 1 with an adjustable alternating current from the feeding single-phase network R. , Mp can be supplied.

In the actual engine operation (washing or spinning) the short circuiter S _{2 is} open; the semiconductor arrangement is controlled via a valve 4 and optionally a further upstream controller 5, e.g. B. according to the principle of phase control, controlled in such a way that a certain speed of the washing drum is reached and maintained. For this purpose, the controller 5 is supplied with at least one actual speed value.

In the braking mode, the short-circuiter S _{2 is} closed and thus the armature winding 2 is bridged, so that a braking effect is achieved and thus the run-down time or transition time of the washing drum between the higher previously reached operating speed and the following lower operating speed can be significantly shortened. The speed control elements of the semiconductor circuit arrangement 1, the control stage 4 and the controller 5 can now be used to set the excitation current of the excitation winding 3 as a function of the speed in a simple manner in such a way that an optimal adaptation between the torque characteristics of the washing drum, which is running out and is braked due to drum friction, and the braking process of the series commutator motor working with a short-circuited armature winding 1 can be achieved.

In order to clarify this situation, FIG. 2 shows, in a solid curve, the torque curve Mj ₃ = f (n) of the washing drum solely due to the drum friction (curve a) and in dashed bsw. The dash-dotted contour shows the regulated braking torque curve (curve b) with the short-circuiter S ₂ closed and with such a regulated modulation of the semiconductor circuit arrangement 1 that a con

509814/0608

'■ - 5 - VPA 73/3277

constant armature current flows. It can be seen that the frictional braking torque, which drops sharply with falling speed η, is easily achieved by the braking torque of the series-wound commutator motor, which works with a short-circuited armature winding and which is supplied with appropriately regulated alternating current via the semiconductor device 1 (triac), which increases accordingly with decreasing speed can be compensated. The dot-dash curve of the characteristic curve b is intended to indicate that the maximum possible excitation current IjJ _1081x can result in the excitation current regulation being limited by the full modulation of the semiconductor circuit arrangement 1 at the lowest speeds.

2 figures

7 claims

5098U / 0608

Claims (7)

■■ 6 - VPA 73/3277 patent claims 1. Washing machine drive with a controllable semiconductor circuit arrangement speed-controllable series-connected commutator motor fed from a single-phase network, characterized in that the transition from a higher to a lower operating speed at otherwise unchanged circuit, the armature winding (2) of the series commutation tormotors can be short-circuited. 2. Washing machine drive according to claim 1, characterized in that a single-pole short-circuiter (S ₂ ) is provided between the outer connecting terminals (21, 22) of the armature winding (2). 3. Washing machine drive according to claim 1 and / or 2, characterized in that in the braking mode with short-circuited Armature winding (2) the excitation current via the controllable semiconductor circuit arrangement (1) in the sense a certain braking torque curve can be controlled and / or regulated. 4. washing machine drive according to claim 3, characterized in that that the excitation current is controlled depending on the speed in the sense of a braking torque that increases with decreasing engine speed. and / or is adjustable. 5. washing machine drive according to claim 3, characterized in that the excitation current after a predetermined time radio - tion can be controlled and / or regulated. 6. washing machine drive according to claim 3 or 4, characterized in that that the excitation current can be specified in the sense of an armature current that is constant during braking. - 7 5098U / 0608 _ 7 - VPA 73/3277 7. Washing machine drive according to one of claims 1 to 6, characterized in that a series commutator motor is provided with the brush axis moved into the neutral zone. 509814/0608 Blank page