Electricity: motive power systems – Induction motor systems – Primary circuit control
Reexamination Certificate
1999-10-12
2001-09-04
Ip, Paul (Department: 2837)
Electricity: motive power systems
Induction motor systems
Primary circuit control
C318S268000, C318S272000, C165S104330
Reexamination Certificate
active
06285157
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a fan cooling device for electrical or electronic components, having a control circuit with a control stage and is designed to control a number of revolutions of a fan motor connected to the control stage as a function of preset values.
2. Description of Prior Art
A fan cooling device of this type is known from German Patent Reference DE 40 24 046 A1. This known fan cooling device has a collectorless d.c. motor as the fan motor, which is driven in a manner wherein the number of revolutions is controlled as a function of an air temperature, wherein a minimum number of revolutions is associated with a lower fixed threshold temperature, and a maximum number of revolutions is associated with an upper fixed threshold temperature. The control circuit here is relatively elaborate.
SUMMARY OF THE INVENTION
One object of this invention is to provide a fan cooling device of the type mentioned at the outset, which permits manifold control options along with a simple design.
This object is attained by means of the characteristics described in this specification and set forth in the claims. A fan motor is an asynchronous motor, which is controlled by phase control. The control circuit includes a microcontroller connected upstream of a control stage. An optocoupler is switched between the control stage and the microcontroller and the microcontroller determines a phase control angle for control of the fan motor as a function of the detection of the crossover of the cullent of a control signal and of the preset values.
A simple control is possible using the asynchronous motor as the fan motor, wherein the provided power can be simply varied with a phase control which is known per se. It is easy to preset a desired control and to match the control to different conditions simply by connecting a microcontroller upstream of an actual control stage of the fan motor. In this case the microcontroller is only under a minimal load, since an optocoupler is arranged between the microcontroller and the control stage, which in addition results in a galvanic separation. The control data can be made available by the microcontroller without elaborate switching measures.
A simple change in the control can be achieved with preset values that include a minimum setting of the number of revolutions, a command value and an actual value. A minimum setting of the number of revolutions can be regulated by a unit for setting the minimum number of revolutions and the command value can be regulated by a command value presetting unit.
Furthermore, for connecting the microcontroller and for signal transmission, a further optocoupler is arranged between a crossover detection circuit and the microcontroller.
A further advantageous aspect of this invention is that the optocoupler is embodied as an opto-triac. As a result, the optocoupler can assume different switching functions.
If the fan is arranged in a switchgear cabinet, the microcontroller is connected to a higher-order switchgear cabinet control and a selection can be made by the switchgear cabinet control or manually. Thus, the microcontroller controls the fan motor either alone on the basis of preset values entered directly into the microcontroller, or on the basis of preset values supplied through the switchgear cabinet control. The fan cooling device for controlling the fan motor can be operated either autonomously or as a function from a higher-order control unit. In this case the fan cooling device can be a part of a total cooling arrangement, which comprises a combination of several control circuits with associated fans, or a combination of at least one control circuit with an associated fan and other cooling apparatus. The cooling devices can be controlled in accordance with a preset program by the switchgear cabinet control. For example, if a fan cooling device breaks down, its break-down can be compensated by other components of the total cooling arrangement. Also, a fan cooling device can be turned off, for example, if it operates incorrectly or if reduced noise generation is desired. These modes of operation can be selected by means of simple programming of the switchgear cabinet control.
REFERENCES:
patent: 6041851 (2000-03-01), Diebel et al.
patent: 43 09 187 (1994-06-01), None
patent: 2296608 (1996-07-01), None
Zündtransformator oder Optokoppler? Schutz vor Fehlzündung bei Thyristor und Triac,elekronikpraxis, Nr., 3, 146, Mar. 1981.
Alex Toth: Leistungsfaktor durch Einchipcomputer gesteuert,Elektronik, 97-101, Dec. 1981.
Hain Markus
Kreiling Jorg
Ip Paul
Leykin Rita
Pauley Petersen Kinne & Fejer
Rittal--Werk Rudolf Loh GmbH & Co. KG
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