DE3614895A1 - METHOD AND DEVICE FOR CONTROLLING THE SPIN SPEED OF LAUNDRY SPIN - Google Patents

Description

description

The invention relates to a method and a device for controlling the spin speed of spin dryers, such as are provided, for example, in program-controlled domestic washing machines of the single-chamber type.

Household washing machines of the single-chamber type often have a rigid outer housing in which a resilient one rotatable chamber is mounted, which serves as a container for washing and rinsing water. One with rotates in the chamber an opening provided rotary drum supported, which is driven by an electric motor at different speeds can be so that programmed washing and rinsing cycles with a given load of laundry items in the drum can be carried out. The individual gears take place at low drum speeds of, for example 45-55 RPM, whereupon a distribution gear taking place at a relatively low speed is at 82, for example UPM, which has the purpose of bringing the wet items of laundry as evenly as possible around the inner circumference of the drum before a high-speed spin cycle with a predetermined drum speed follows, to throw the rinsing water out of the laundry items by centrifugation, so that the laundry items finally be in a moist state suitable for rapid final drying.

If the wet laundry items are not distributed evenly enough on the inner peripheral wall of the drum, before the spin-drying cycle is started, the unbalanced mass of wet items of laundry represents a significant periodic dynamic imbalance loading within the drum for the drum support during the spin cycle.

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At high spin speeds, such dynamic periodic imbalance loads cause considerable loads Vibrations and can affect the components of the machine, e.g. the drum bearings, the chamber spider with which the Bearings are supported, the chamber suspension and the like, all of which are designed to the able to withstand periodic loads at maximum spin speeds under the most unfavorable conditions, are exposed to considerable loads.

In addition, if the amplitude of these vibrations is unduly large, the vibrating chamber assembly may the surrounding housing of the machine brush or touch, so that not only annoying noises arise, but corruption may also occur. Follow the maximum permitted spin speed must be limited in such a way that these extreme imbalance conditions in the drum is taken into account, even if such states are only in a small number of Operations of the machine occur.

Various proposals have been made to limit these dynamic imbalance loads. For this purpose, a variable was recorded which is related to the extent of the imbalance or the eccentricity the rotating drum load, and the recorded variable was used during the spin cycle prevent excessive vibrations occurring. For example, the proposal made by the Drum motor to monitor the current consumed during the spin cycle and the determined motor current to the Control the spin speed to use.

The invention is based on the object of a method and a device for controlling the spin speed depending on vibrations of the drum and / or the drum suspension caused by imbalance

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create during the spin cycle itself by monitoring a variable that is directly related is related to the extent of the stress caused by the imbalance and has no significant external influence Is subject to factors. One such variable is the extent of the periodic acceleration of the spring loaded Chamber / drum arrangement as a whole.

It can be assumed that the periodic dynamic load that is applied to the components of a washer-extractor due to an unbalanced load acting on the drum, is proportional to the product of the imbalance located mass and the square of the drum speed, while an inverse relationship to the Total mass of the rotating system. It was found that one in one perpendicular to the drum axis component of the vibration acceleration of the elastically mounted chamber / drum arrangement, caused by unbalanced drum loading, is directly representative of the extent the dynamic load caused by such an imbalance.

The above object is achieved by the invention specified in the patent claims.

With the aid of the method according to the invention and the method according to the invention Device will direct the dynamic consequences of an unbalanced drum loading felt in the vicinity of their source of formation in the form of accelerations caused by the imbalance, and a much more precise control signal can be obtained for setting the spin speed, than when using secondary variables, e.g.

the motor current or the drum speed fluctuations, would be possible.

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The most suitable place to feel the acceleration and the direction of the sensed acceleration component can be determined through experiments, as this depends on the special properties of the suspension system and depends on other factors.

By suitable selection of the named location and the component direction it is possible to ensure that the sensed acceleration value exactly matches the dynamic imbalance stress reflects, whereby the stress is caused by the inertia of the mass of the laundry inside the drum. The stress can be determined through experiments, for example with the help of a strain gauge determine. If the perceived variable is a so-called secondary variable, e.g. the fluctuating motor current or the fluctuating drum speed, then the advantage mentioned cannot be achieved, and one has to deal with an essential one be satisfied with inaccurate controls.

The invention makes it possible to use a machine, e.g. a washing machine equipped with a spin function, a spin dryer, as it is used in laundries or in the household, or a centrifuge, up to one relatively high available maximum spin speed without the need to separate the individual Design components mechanically stronger. The stress on the components is significantly lower than in the State of the art, since when the drum is noticeably imbalanced, the spin speed is automatic limited and set to a safe value below the available maximum spin speed. at other loads, however, which are more or less balanced, i.e. in equilibrium, are available Maximum spin speed available for safe operation, so that you can then centrifuge effectively and, for example Water out of the clothes.

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In the device according to the invention there is a mass inertia switch for use. This switch can be spring-loaded so that it opens briefly when responding and then closes again. But it can close briefly and then open again. That short opening or short closing takes place when the periodic acceleration of the drum / chamber arrangement reaches a predetermined limit value. The duration of each pulse of the output of the mass inertia switch is very short, in some cases it may be that the pulse duration is too short to ensure a suitable speed control of the motor. If the consecutive time periods in which the motor excitation is reduced are too short, the The engine speed may gradually increase and eventually reach a value above the predetermined one Acceleration peak value lies. This then means that the control is no longer working properly.

In order to increase the duration of the signal pulses, the inertial mass switch device is used preferably equipped with a time delay device. This can be be a mechanical delay device assigned to the switch contacts, the time spans between the initial opening and then closing again (or vice versa). However, one is preferred electrical time delay to control the pulse duration of the output signal.

For example, the inertia mass switch can control the energization of a normally closed relay, its contacts in series with the low speed or zero speed input the motor speed control device are switched so that the relay contacts are synchronized with the Vibration acceleration of the chamber / drum arrangement can be opened, and a time delay condensation

Sator lie in the circuit of the relay winding, so that the re-closing of the relay contacts is delayed. In in such a case, the inertia mass switch would be a spring loaded, normally open switch be that when the chamber / drum assembly a reached predetermined acceleration peak value, periodically by the then prevailing inertial forces shorts and opens again. The capacitance of the capacitor is chosen so that the engine speed increases is held at a constant value which is the predetermined peak dynamic acceleration value Beginning of the periodic closing and opening of the contacts of the inertia switch corresponds. Too little Capacitance value would lead to a rising characteristic curve of the controlled motor speed while on large capacitance value would cause the motor and drum to "chase".

It is possible to control the speed of the motor during the spin cycle by supplying power to the motor Intermittently interrupted for the duration of the pulses of the perceived output signal to lead. In order to eliminate these problems, the pulse-shaped sensor signal is preferably used to to switch the engine speed controller intermittently between a higher and a lower one Speed value above zero, e.g. between 1250 or 1500 RPM drum speed and 500 RPM drum speed, in order to obtain a set speed between these two outer speed values. This speed value is a speed at which the periodic actuation of the inertia switch is initiated by the predetermined peak inertia sensed chamber / drum acceleration.

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The acceleration sensor devices according to the invention are designed in such a way that they influence the spin speeds during the spin cycle itself, thus excessive dynamic loads on the drum / chamber arrangement during the spin cycle due to imbalance loads the drum loaded with laundry items can be avoided. There is, however, another form that is more dynamic Disturbances that often occur with spin dryers, namely vibrations that are large The amplitude and frequency of the chamber / drum arrangement are due to the natural resonance the suspension. These vibrations occur at a very low, critical drum speed, shortly after Starting the drum when the drum is loaded unbalanced.

To counter this problem, the invention provides a device with a second acceleration sensor and a responsive control device (claims 18 and 19).

The invention is also applicable to spin dryers such as those used in laundries and households for single-chamber washing machines with spin option. However, the invention is equally applicable in the case of other types of centrifuges for household, industrial, commercial and agricultural operations and the same.

The following are exemplary embodiments of the invention explained in more detail with reference to the drawing. Show it:

Fig. 1 is a rear view of the interior of a single-chamber washing machine with spin-speed counter control,

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Fig. 2 is a side view of the machine shown in Fig. 1,

Fig. 3 is a sketch of a mass-inertia switch as an acceleration sensor for the

Machine according to Figs. 1 and 2,

Figure 4 shows an alternate embodiment of a mass inertia switch for use as an acceleration sensor,

Fig. 5 is a circuit diagram of a control circuit with mass inertia switch for the motor speed control, with only the essential parts of this circuit

are shown

6 is a graph showing the operation of the spin speed control the drum illustrates

Fig. 7 is a block diagram showing the relationship

the various components and functions of the control device in the embodiment 1 to 6 illustrate

light, and

Fig. 8 is a block diagram, similar to Fig. 7, of a second embodiment of the invention.

1 and 2 show a program-controlled single-chamber domestic washing machine 10 with high-speed spinning equipment. The machine 10 has an outer housing 11, which stands on the floor and has a flap 12 in its front wall. In the housing 11 is

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with spring suspensions 14 and shock absorbers 15 a non-rotating chamber 13 is suspended on its lower An electric motor 16 is mounted on the outside. The opening of the chamber is elastic by a bellows 17 with the Frame of the flap 12 sealed. A perforated centrifuge drum 18 is horizontal with its axis 19 in Bearings 20 rotatably mounted, the bearings 20 being carried by a spider 21 attached to the rear wall of the chamber 13 will. The motor shaft 27 is via a

-JO speed reduction effecting belt drive 22 on the shaft of the drum 18 is coupled. On the upper outside of the chamber 13 is a mass inertia switch trained imbalance acceleration sensor 25 mounted. The sensor 25 is located in the Proximity, preferably in a plane 26 passing through the drum shaft axis 19 and the center of gravity 28 of the suspension system runs. The sensor is on that side of the Axis 19 arranged opposite the center of gravity.

The sensor 25 is mounted on the chamber 13 to components the chamber vibration acceleration in the horizontal direction, as in FIG. 1 by a double arrow 30 indicated to feel. The direction lies in a plane perpendicular to the drum axis of rotation 19.

The sensor 25 is designed as a (mass) inertia switch. Its structure is shown in FIG. 3.

As Fig. 3 shows, the switch 25 includes a fixed contact piece 32 bearing housing 31 upper end of a leaf spring conductor 34, the lower end of which is set in the housing wall, is one with the fixed contact piece cooperating movable contact piece 33 mounted, which by the leaf spring of the stationary contact piece 3 2 is biased against a rear stop 3 6. In the housing wall

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there is an adjusting screw 37 with which the leaf spring 34 can be adjusted for the required contact if necessary. The switch connections are labeled 38 and 39, respectively.
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The switch is mounted on the chamber 13 in such a way that the longitudinal extension of the leaf spring is perpendicular to that shown in Fig. 1 is shown arrow 30, while the (not shown) center line of the two contact pieces 32 and 33 parallel to the arrow 30 runs so that the contact pieces on the can address horizontal acceleration components of the chamber in the direction of arrow 30 in that the normally open contacts 32 and 33 close. The mass of the movable contact piece 33 and the Strength of the leaf spring 34 are chosen so that the contact piece 33 is then just in the closed position with the fixed contact piece 32 moved to close the switch when a predetermined acceleration peak value is reached, whereupon a short time later again the movable contact piece of the Contact piece 32 is released by the force of spring 34. On this particular machine, the peak value is the acceleration chosen to be 15 g, which corresponds to about half the "fractional value" at which the bearings or others There is a high probability that parts of the machine will be damaged.

Fig. 5 shows the speed control circuit for the drum motor 16. The circuit includes the normally open inertia switch 25 shown in FIG Motor is e.g. an AC commutator motor with an armature 40 and a field winding 41, that between a live terminal 42 and a neutral terminal 43 in series with a solid-state speed control module (designed as a microprocessor) 44 lies. The module 44 varies the engine speed

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by varying the firing angle of a triac 45 or another suitable semiconductor component. Will If the ignition angle is set to a maximum, the engine runs at a selected maximum speed, which is determined by the individual connections at the inputs of the module depends. The module has an input pin 46 through which the maximum speed of the motor for the desired maximum spin speed by applying a mains voltage is set, e.g. for 1100 or 1250 RPM spin speed. However, the mains voltage from the module pin 46 removed, the module controls the maximum engine speed to a maximum ignition angle such that the speed corresponds to a spin speed of 500 rpm.

As FIG. 5 shows, the input pin 46 of the module 44 through the normally closed contacts 47 of a relay 48 and through a timing mechanism 49 of the machine connected to the mains connection 42, so that when the relay is closed, the module is the full engine speed and delivers the full spin speed. The relay winding 50 is in series with a 12 volt DC power supply 51 and with the normally open contacts of the inertia switch 25. In parallel with the Switch 25 is a time delay capacitor 52.

7 shows, in block diagram form, the components and functions of the control device in connection with a normally open or a normally closed inertia switch. The module is through a dashed rectangle 44 is indicated, and it contains a comparator 53, which is an actual engine speed signal, supplied from a motor shaft tachometer 54 through a processing circuit 55 compares with one Set speed signal, which comes from a motor speed register 56 and is sent from a set speed multiplexer.

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is chosen. The inertia switch 25 and the relay assigned to it with a delay circuit are connected to the input pin 46 leading to the desired speed multiplexer of module 44 connected. Numeral 49 denotes a program flow controller of the washing machine. The output signal of the comparator 53 reaches a triac opening time transmitter 58 and from there via a gate pulse generator 59 to motor triac 45.

The mode of operation of the control device will now be explained with reference to FIGS. When the spin cycle the machine is started and the ignition angle of the module is set to maximum, the contact pieces are of the inertia switch is open and the relay 48 is de-energized, i.e. its contacts 47 are closed, see above that the module 44 is set for the maximum motor / drum speed, e.g. for a drum speed of 1500 rpm is. The motor starts to spin the drum and accelerate the drum rotation. When the one in the drum items of laundry located unevenly during the previous, low-speed distribution gear have been distributed, there is a certain unbalanced mass distribution of laundry items in the drum before, and this imbalance leads to a progressively stronger periodic vibration of the elastically mounted chamber / drum arrangement, while the spin speed increases.

The periodic or cyclic acceleration resulting in the direction of arrow 30 in FIG. 1, that of the dynamic Corresponds to the stress on the drum bearings and the bearing spider due to the unbalanced load, acts on the inertia switch 25. The line 60 shown in FIG. 6 represents the periodic acceleration. When the acceleration value reaches a predetermined peak value (line 61 in FIG. 6), in this case 15 g,

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enough, this is sensed by the switch 25, moving the switch contact pieces through the inertia of the movable Briefly close contact piece 33 (line 62), whereupon the contact pieces open again a short time later (line 62), due to the spring force of spring 34.

The line 63 in FIG. 6 represents the opening and closing of the inertia switch 25 over time. This line of lines has short peaks 64, which represent the closing periods of the switch 25. Immediately to Beginning of one of the peak pulses 64 of the switch 25, the relay 48 is energized, so that the relay contact pieces Open 47, thereby disconnecting module input pin 46 from line 42. As a result, it will begin to adjust the motor towards a lower drum speed of 500 RPM so that the motor speed drops. After the contacts of the inertia switch are opened again, the relay contacts are closed again 48 delayed by the discharge of the capacitor 52, which is now charged via the relay winding 50. This has the consequence that relatively wide gaps 65 arise in the characteristic curve of the motor excitation or motor supply. These gaps 65 identify the periods of time in which the input pin 46 is disconnected and the engine speed is controlled towards a lower drum speed of 500 RPM.

In the line 66, the double-line segments indicate the periods of full motor supply when the module is the Selects a higher maximum speed of 1250 RPM drum speed. The gaps 65, however, show those time spans in which the motor is fed with reduced energy, i.e. when the drum speed is 500 RPM corresponding motor speed is selected. As a result of this control, the mean energy feed lies of the engine over a number of several cycles between

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the full and the reduced values, so that the motor is set to an intermediate drum speed between 1500 and 500 RPM is regulated as long as the dynamic acceleration of the drum continues at the predetermined value and this acceleration is sensed by the inertia switch 25 so that it synchronizes with the vibrations Signal is generated.

Provided that the time delay caused by capacitor 52 is sufficient, the engine will run at an intermediate speed regulated, which corresponds to that speed at the predetermined peak acceleration the drum of 15 g was present. This follows from the fact that every time the relay 47 at the end of one of the Gaps 65 closes again and the engine speed is too far below a corresponding to the predetermined peak value Value has decreased, the inertia switch not during the next acceleration cycle or not during the following acceleration cycle following acceleration cycle responds to the next peak pulse 64 and the corresponding gap 65 to create. The pulsing of the motor power supply stops and the power supply continues for as long as a maximum drum speed of 1250 RPM continued until the engine speed has again a value at which the Respond to the inertia switch and the control system and adjust to an intermediate speed.

If the time delay in re-closing relay 48 is insufficient, the motor will operate accordingly controlled by a slowly increasing intermediate speed characteristic. Too great a time lag caused If the capacity value is too high, however, the result is that the motor reaches the set intermediate speed "runs after". A suitable capacitance value is 18OuF in a special case.

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The device described above has considerable advantages: the device is easy to manufacture and assemble easy and cheap. By automatically limiting the spin speed to a value that is not dynamic Causes stress above a predetermined safety value, regardless of the extent of the "imbalance" drum loading, enables safe start-up and maintenance of the maximum available Spin speed for a particular machine without affecting the strength of the machine components that make up the are exposed to dynamic loads, would have to be designed to be particularly strong.

The invention makes it possible to manufacture finished machines that, for example, have a maximum spin speed of 1100 UPM have to convert to an increased spin speed of 1250 RPM or 1500 RPM by adding a more powerful Motor provided and the control device described is used, which ensures that the said higher spin speeds for most drum loads, which are well distributed and not worth mentioning have unevenly distributed mass, can be exploited. The applicant has actually found out that the conversion of a machine designed for a maximum spin speed of 1100 RPM to a maximum Spin speed of 1500 RPM when controlling the spin speed to a safe value using the control device according to the invention higher spin speeds than 1100 RPM are possible with 82% of the usual drum loads with items of laundry, while with 42% of the Loads can be safely spun at 1500 RPM.

In the case of serious unbalanced loads, the control device ensures that the spin speed is limited, and that the safety level of the dynamic stress is not exceeded. The sluice

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the speed is always set to the maximum permissible value limited for the respective laundry item loading of the drum without incremental steps being used. The response behavior provided by the acceleration sensor is directly related to the imbalance loads, caused by such accelerations, in contrast to conceivable arrangements, in which a secondary parameter is sensed and processed, e.g. the fluctuation of the motor current or the Drum speed.

The design of the engine is simplified because it is no longer necessary to build means in the engine In the event of a pronounced unbalanced load, lower the high engine speed. The contact wear of the Inertia switch is minimal, as the contact pressure when making contact is practically zero, so that the contacts have a much longer service life than the usual microswitches and relay contacts would be expected.

When the inertia switch 25 has a second fixed contact behind the movable contact piece 33 instead of the rear stop 36, it could be of the movable contact piece 33 in such cases in which extremely large chamber accelerations are felt, which e.g. indicate a fault in the module 44 are due. Such an additional contact is part of a switch-off circuit or shutting down the machine if, in an emergency, the moving contact piece closes the contact.

Finally, it was found that cycling the controlled motor speed between full spin speed and a spin speed of 500 RPM no interference in the power line or radio reception

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caused. Such disturbances could be expected due to the cyclical on / off switching of the motor current.

4 shows an alternative embodiment of an inertia switch 25A, which can be used in place of the normally open switch 25. This one usually closed switch, the movable contact 33A of which is slidable in a cylindrical housing 31A is added with a screw cap 3IB, has a movable contact piece, which is held by a helical spring 34A against a fixed contact piece 32A on that of the Cap 3IB far end of the cylinder is pretensioned. The switch connections are labeled 38A and 39A. The switch would be set so that it was under the influence a horizontal acceleration of the chamber of 15 g, caused by an out of equilibrium Weight of 1 kg at a spin speed of 1100 RPM, just opens. This form of the normally closed Switch is to be preferred because a longer service life and greater reliability can be expected from it are.

Instead of the control circuit shown in FIG. 5 with the relay 48 and the capacitor 42, the would normally closed switch 25A is a differently configured circuit for providing a pulse signal with a sufficiently large Require pulse width for module input pin 46. For example, switch 25A could be in conjunction with a solid-state switching module, which is a time delay device contains, used to send the required pulse signal to input 46 of the engine speed control module admit. With such a configuration of the circuit, the inertia switch 25A would only be the Require processing of very small currents, so that an erosion of the contacts would hardly have consequences because of the contact pressure relatively high when normally closed

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The use of a normally closed inertia switch, as shown in Figure 4 also provides an operational safety function for the system; because in the event that a line leading to the switch loosens or breaks, or the biasing spring of the If the moving contact piece breaks, the control device automatically sets the spin speed to the lower one preset value, in this case 500 RPM.

Fig. 8 is a block diagram of a second embodiment of the invention. In the sketch are the same and similar Parts as in FIG. 7 are provided with corresponding reference numerals. In this case the imbalance is inertia switch 25 or the switch 25A as described above mounted on the chamber 13 in order to activate the acceleration address, which is caused by an unbalanced load on the drum 18 according to FIG. 1, however the inertia switch is not used to control the motor excitation and the spin speed by means of a pulse Control signal continuously. Rather, the switch 25 or 25A is via a buffer 70 connected to a modified microprocessor module 44B which also contains a spin speed register 71 and is designed so that it responds to a memory signal coming from the memory 70 to determine the engine speed to a predetermined value that is lower than the maximum available spin speed.

The system shown in Fig. 8 is therefore suitable for a washing machine of known type in which the safe Maximum spin speed, e.g. 1100 RPM with practically any eccentricity of the laundry load in the Drum is reached. Retrofitting is desirable

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for a maximum spin speed of e.g. 1250 RPM. This can be done safely and without reinforcing certain stressed Components of the machine are done by installing this embodiment of the control device according to the invention and the module 44B is set to respond to a memory signal transmitted by the first Opening (or closing) the inertia switch is initiated when the switch reaches a predetermined peak value feels the case acceleration of 15 g. Although the switch contacts continue as long as there is a signal how the predetermined acceleration continues is used for the generation of a pulse-shaped control signal therefrom no use made. Instead, module 44B responds to the memory signal by reading the engine speed to a controlled value, which corresponds to a spin speed of 1100 RPM (this is as safe value known for all loading conditions) and maintains this speed for the duration of the spin cycle.

So you can not set the spin speed for any load that is sufficiently evenly distributed To operate the inertia switch 25 or 25A, set it to the high maximum value of 1250 RPM. If, however the switch 25 or 25A senses that an acceleration due to uneven loading during the Increase in the spin speed in the spin cycle reaches the value 15 g (regardless of whether the Spin speed of 1100 RPM is reached or not), the switch generates a memory signal, and immediately then the engine speed is based on module 44B the well-known safe spin speed of 1100 RPM is set.

In the manner described above, a conventional Machine with a maximum spin speed of 1100 RPM safely to a higher value of a maximum

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Spin speed of, for example, 1250 RPM, which is suitable for most loads, can be converted without there is a need to reinforce the components of the machine so that they can withstand any higher dynamic loads can withstand due to unevenly distributed loads. This is achieved in that the Control device ensures that higher dynamic loads can never occur.

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Claims (25)

Claims 1. A method of operating a spin dryer, characterized in that a component of the acceleration is monitored directly during a spin cycle and a perceived value of the component is used for this purpose to set the spin speed to a suitable value during the spin cycle. 2. Spin dryer, characterized by a device for directly monitoring a component of the acceleration during a spin cycle, as well as using a felt value of the component to reduce the Set the spin speed to a suitable value during the spin cycle. Radeckestraße 45 SCOO Müncnen 60 Telephone (089) 883603/883604 Telex 5212313 Telegrams Patentconsult SonnenBerger Straße 43 620D Wiesbaden Telephone (06121) 562943/561998 Telex 4186ΪΪ7 Telegrams Patentconsult 3. Spin speed control device for a spin dryer, which is an elastically mounted arrangement of a non-rotatable outer chamber and a motor-driven centrifuge drum which is supported in and by the chamber, has, characterized by a sensor device (25) which is designed such that it directly the vibration acceleration the chamber / drum arrangement, caused by an imbalance in the loading rotating drum, senses and monitors during the spin cycle that the sensor device continues to be designed in such a way is that it generates an output signal which is indicative of the extent of the acceleration felt, and that further means is provided for controlling the spin speed as a function of the Output signal. 4. Apparatus according to claim 2, characterized in that the sensor device is designed such that it generates an output signal indicating that the amount of acceleration sensed has reached a predetermined peak has achieved, and in that a device responsive to the output signal is also provided which sets the speed of the motor during the spin cycle to a value that is lower than the maximum available spin speed corresponding value. 5. Apparatus according to claim 3, characterized in that the device responsive to the sensor output signal is designed such that it sets the engine speed to a value that of the spin speed corresponds to at which the predetermined peak value of the perceived acceleration was reached. 6. Apparatus according to claim 5, characterized in that the peak value is chosen so that it is a predetermined Safety value for a dynamic inequality 24/25 weight stress below a "fractional value" for the machine in question corresponds, so that regardless of the mass and the eccentricity of the unbalanced Drum load inside the drum the spin speed is set to such a value / that the "fractional value" is never reached. 7. Device according to one of claims 3 to 6, wherein the sensor device is responsive to mass inertia. 8. Apparatus according to claim 7, characterized in that the sensor device is an electrical mass inertia switch device which is mounted on the housing to accelerate the vibration during to feel the spin cycle and respond to it, and that the switch device is designed and arranged is to generate the signal in response to the predetermined peak acceleration being reached is. 9. Apparatus according to claim 8, characterized in that the switch device is designed such that it works cyclically in order to generate a pulse-shaped output signal synchronously with the perceived vibration accelerations to create. 10. The device according to claim 9, characterized in that that the means for controlling the speed of the motor includes means for reducing the excitation of the Motor (or to shut down the motor completely) during each pulse of the signal while within the Pulse pauses the motor is fully excited, or vice versa. 11. The device according to claim 10, characterized in that the motor has a speed control device, which corresponds to a relatively high speed value 25/26 36H895 ι according to the maximum spin speed, or on one relatively low speed value, which can assume the value zero, is adjustable, and that the speed control device is adapted to respond to the switch output by starting or during the duration of each pulse of the signal a reset to a lower speed value that corresponds to the value Can assume zero, but returns to the higher speed value at the end of each pulse, so that the '0 total amount of energy fed into the motor is the mean value corresponds to the amounts of energy input during successive pulses and pulse pauses, so that the The engine runs at a controlled speed that is between the relatively high speed value and the relatively low speed value Speed value, which can be zero, lies. 12. Apparatus according to claim 10 or 11, characterized in that the mass inertia switch device is equipped with an electrical time delay device, for example, which the duration of the Signal pulses during which the excitation of the motor is reduced or made zero, increased. 13. The apparatus according to claim 12, characterized in that the mass inertia switch means the excitation a normally closed relay whose contacts are in series with the low speed or Zero speed input of the engine speed control device (e.g. a microprocessor module) so that the contact pieces of the relay open synchronously with the vibration acceleration of the chamber / drum arrangement, wherein the time delay means comprises a time delay capacitor inserted into the relay winding is switched to delay the re-closing of the relay contacts. 26/27 36H89 14. The device according to claim 13, characterized in that the mass inertia switch is a spring biased normally open switch is due to inertial forces when the periodic acceleration the chamber / drum arrangement the predetermined Peak value reached, periodically short .circuits and then opens again, and that the capacitance of the capacitor is chosen so that the engine speed remains constant at a value which see the predetermined peak value of the dynamis Acceleration at the beginning of the periodic closing and re-opening of the contact pieces of the mass inertia switch is equivalent to. 15. The apparatus according to claim 12, characterized in that the mass inertia switch is a spring is biased, normally open switch, which is opened by mass inertia forces, and that the Time delay device comprises a solid-state switching device with a time delay. 20th 16. Device according to one of claims 4 to 11, characterized in that the engine speed control device responds to the beginning of the sensor output by increasing the speed of the drum motor to one constant, predetermined safety spin speed value that is less than the maximum available Spin speed, set for the remainder of the spin cycle. 17. Apparatus according to claim 8 and 16, characterized in that the microprocessor or a differently designed one Motor speed controller immediately after detecting the predetermined peak acceleration value responds to the beginning of the opening or closing of the switch contact pieces, and that it immediately adjusts the engine speed value to the required predetermined safety 27/28 36H89B sets the security value and holds it at this value, whereby the security value does not necessarily correspond to the predetermined Acceleration peak value corresponds, but can be a security value known per se. 5 18. Centrifuge, in particular spin dryer, with a resiliently mounted arrangement of rotatable centrifuge drum in a stationary outer chamber or housing, characterized by a first acceleration sensor and an engine speed control device according to any one of claims 3 to 17 for adjusting the engine speed on high spin speeds during the spin cycle, and also characterized by a second Acceleration sensor that detects vibrations in the chamber / drum arrangement at critical low drum speeds responds, in which due to resonance of the suspended arrangement oscillations of large amplitude and low frequency can be generated. 19. Centrifuge according to claim 18, characterized in that the second sensor acts on a control device, which is designed in such a way that the started spin cycle is canceled and a further distribution cycle is initiated. 20. Centrifuge according to claim 18, wherein the control device responsive to the second sensor is the centrifuge persists. 21. A method for operating a centrifuge, in particular a spin dryer, its motor-driven drum in a surrounding, non-rotating housing, e.g. a chamber, rotatable as part of an elastically mounted Arrangement is stored, characterized in that the unbalanced loading of the drum vibration caused during the spin cycle 28/29 Acceleration of the housing / drum arrangement felt directly is that an output signal is derived from the sensing process, which is indicative of the extent the perceived acceleration, and that the spin speed is set as a function of the output signal will. 22. The method according to claim 21, characterized in that the derived output signal is indicative thereof is that the sensed acceleration has reached a predetermined peak and that it is used to to control or adjust the speed of the motor during the spin cycle so that the spin speed reached is less than the maximum available spin speed. 23. The method according to claim 22, characterized in that the derived output signal is used to set a spin speed which corresponds to that speed at which the predetermined peak value the perceived acceleration was achieved. 24. The method according to any one of claims 21 to 23, wherein the output signal from a responsive to mass inertia Device, e.g. from a mass inertia switch, is derived. 25. A method for controlling the speed of an electric motor, in particular the drive motor of a centrifuge drum, which has a maximum speed value and a lower speed value, which by a command signal can be selected, characterized in that the command signal is in the form of a pulse train is provided, with the result that during each pulse duration the high speed value and during each Pulse pause the lower speed value is selected, 29/30 1 and vice versa. 30th 36H895