JPH0449922A - Electrically driven - Google Patents

Abstract

PURPOSE:To prevent burning due to restriction of a motor at a time of start by providing a controller which detects an overload from the revolution number of the motor and changes the revolution of the motor based on a detection output. CONSTITUTION:When a switch 1 is turned ON, a motor 2 first revolves in normal direction, number of revolution (N) of a motor shaft is detected by a revolution number detector 4 through a photoelectric sensor 3. Thus detected revolution number is compared by an operator 5 with a set revolution number (N0) which is preliminarily set as an overloaded state, and if (N) is larger than (N0), that is N > N0, the motor continues its normal revolution. If (N) is equal to or smaller than (N0), that is N <= N0, the revolution of the motor 2 is reversed instantly by a revolution direction controller 6 which receives an output from the revolution number detector 4, and at the same time, the number (n) of the reversed revolutions is counted by the operator 5 and then, the motor 2 revolves in the normal direction again. Further, the revolution number (N) is detected again, and if N > N0, the motor continues to revolve in the normal direction. On the contrary, if N <= N0, the motor 2 is made to revolve in the reversed direction instantly, and after that, a sequence of operations, that is, the number of reversed revolutions is counted, the motor 2 is returned to the normal revolution and the revolution number is detected again, is repeated. When the number (n) of the reversed revolutions reaches a preset number (n0), the motor 2 is stopped.

Description

[Detailed description of the invention] Industrial applications The present invention relates to an electric cooker such as a mixer.

Conventional technology In the past, in this type of electric cooker, the motor was often restricted or overloaded when starting up depending on the load condition, and fuses and breakers were installed to prevent the motor from burning out. It was common for the circuit to be cut off in the event of an abnormality.

Problems to be Solved by the Invention In such conventional electric cookers, although the motor is protected by circuit interruption, the cause of the abnormality is not removed.
For example, in the case of a mixer, it is not possible to restart it as is.
It is necessary to remove the material caught between the knife and the container.
It was inconvenient to use and dangerous. Furthermore, when a fuse is provided, there are problems such as the need to replace parts.

The present invention takes into consideration the above-mentioned conventional drawbacks and aims to provide an electric cooking appliance in which the motor is not restricted during startup.

Means for Solving the Problems In order to achieve the above object, the present invention includes an overload detection device that detects overload based on the number of rotations of the motor shaft, and a device that detects the rotational direction of the motor based on the output of the overload detection device. The motor rotation direction control device is equipped with a switching motor rotation direction control device, and further limits the number of times the motor is switched between forward and reverse rotation, and then stops the motor.

Operation The present invention has the above-described configuration, so that the number of rotations N counted by the overload detection device is the number of rotations N preset as the overload state of the motor. If it is smaller than , the υ motor rotation direction control device is activated by the output of the overload detection device, the motor instantaneously reverses, then rotates forward again, counts the number of rotations again,
If the number of rotations is greater than No, normal rotation continues, and if the number of rotations is less than No, instantaneous reverse rotation occurs again.

However, when the number of times of forward/reverse switching reaches a preset number of times, the motor stops.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to FIGS. 1 and 2.

In the figure, when the switch 1 is turned on, the motor 2 first rotates in the normal direction, and the rotation speed N of the motor shaft is detected by the rotation speed detection device 4 via the photoelectric sensor 3, and is set in advance as an overload state by the calculation device 5. The rotation speed N. compared to
If N>No, the motor continues to rotate in the normal direction. However, if N≦No, the motor 2 receives the output of the rotation speed detection device 4 and is instantaneously reversed by the rotation direction control device 6. At the same time, the number n of reverse operations is currented by the calculation device 6, and the motor 2 is rotated forward again. do. And further rotation speed N
is detected, and if N>No, normal rotation continues. Alternatively, if N≦No, instantaneous reversal, counting of the number of reverse rotations, and detection of nine normal rotations are repeated, and the number of reverse rotations n is a preset number n. When this happens, motor 2 is stopped.

Effects of the Invention As is clear from the above description, the present invention provides a device for detecting overload of a motor, and a motor rotation direction control for switching the rotation direction of the motor in response to the output of the overload detection device. The system also limits the number of times the motor switches between forward and reverse rotation, and then stops the motor, so if an overload is applied to the motor, the motor instantly reverses and then rotates forward for a predetermined number of times. The load (material) causing the overload can be removed repeatedly within the range, improving the usability of an electric cooker such as a mixer, and providing a highly safe electric cooker.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an electric cooker according to an embodiment of the present invention.
FIG. 2 is an operation flowchart of the electric cooker. 1...Switch, 2...Motor, 3.
... photoelectric sensor, 4... rotation speed detection device, 6.
...Arithmetic device, 6...Rotation direction control device. Name of agent: Patent attorney Shigetaka Awano and 1 other person1-
Z-i...te F--j-ta-41i 6-hook hook 1

Claims (3)

[Claims] (1) An electric cooking appliance that includes an overload detection device that detects overload of a motor, and a rotation direction control device that receives an output from the overload detection device and switches the rotation direction of the motor. (2) Claim 1 in which overload is detected based on the rotational speed of the motor.
Electric cooker listed. (3) The electric cooking appliance according to claim 1, wherein the number of times the motor is switched between forward and reverse rotation is limited, and then the motor is stopped.