JPS63299709A - Electrically driven cooking machine - Google Patents

Abstract

PURPOSE:To make it possible to continue cooking even in case of the tentative flow of overcurrent by detecting continuously the number of slow revolutions of a motor for a certain time or by operating an overcurrent circuit breaker when the number of slow revolutions is detected again a certain time after detecting the number of slow revolutions. CONSTITUTION:A speed detection section 4A inputs a detection signal of the number of revolutions of a motor 1A in a control circuit 3A. When the motor 1A is in a state overloading or locking, the number of slow revolutions is detected in the control circuit 3A. When the number of slow revolutions is detected again after passing a certain time or when the number of slow revolutions is detected continuously for a certain time, the breaking operation is performed by a by-pass circuit being branched from bb point by flowing the current capable of operating to an overcurrent circuit breaker 2A immediately from aa point. And, at this time, a certain time is longer than the time required for one time detection. In a locking state of motor, an optional time is set by confirming the time before the motor 1A becomes abnormal to the motor of each cooking machine.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electric cooking machine having a function of preventing burnout of the electric motor.

(Prior Art) Conventional 1 Electric cooking machines, such as mixers (not shown), which grind and cut ingredients by rotating a cutter inside a container using rotational force from an electric motor, are highly sensitive to the quality of the ingredients.
The load condition changes greatly depending on the amount. Therefore, in order to prevent the electric motor from being burnt out due to continued overload or locking, a motor is used as shown in FIG. 2 of Japanese Patent Application Laid-Open No. 60-212128.

There are those that detect an overcurrent in the motor in an overloaded or locked state and operate an interrupter when the overcurrent occurs, and there are those that are simply equipped with an overcurrent breaker as shown in FIG.

(Problems to be solved by the invention) However, in the conventional configuration, the inrush current when the motor is activated is large, so the current is detected and cut off.
If you do not take a considerable difference between the normal current of the overcurrent breaker when it is steady and the current that flows when the motor is overloaded or locked, the overcurrent breaker may shut off incorrectly, or there may be a slight sticking or resistance of the ingredients during cooking. However, when an overcurrent temporarily flows, the actual load on the motor is not a process overload, and there is a problem that the circuit breaker may be activated even though cooking should continue.

(Means for Solving the Problems) The present invention has been made to solve the above problems, and detects the rotational speed of the motor using an electric motor and an overcurrent breaker connected to the electric motor.

And does it continue to detect the low rotational speed of the motor for a certain period of time?

The structure includes a rotation speed detection/calculation/overcurrent breaker operation circuit that supplies sufficient operating current to the overcurrent breaker when detecting a low rotation speed again after a certain period of time after detecting the low rotation speed. be.

(Function) By doing this, it is possible to instantly detect the extremely low rotation speed when the motor is overloaded or locked.
The arithmetic circuit determines whether the problem is temporary or not after a certain period of time. If the rotation speed is temporarily low due to a slight load on the material, the overcurrent breaker will not operate unless the rotation speed is low even after a certain period of time.

Cooking will not be interrupted midway. In addition, when the engine is really overloaded or locked, the overcurrent breaker operation circuit is activated by detecting a low rotational speed even after a certain period of time.

(Example) Figure 1 is a circuit block diagram of the main part of this example.
is an electric motor, and two overcurrent circuit breakers are connected in series, and a rotation speed detection/calculation/overcurrent circuit breaker operation circuit 3A (hereinafter referred to as circuit 3A) is connected in parallel to this circuit. 4A is a rotation speed detecting section which inputs a detection signal of the rotation speed of the electric motor 1 to the circuit 3A.

6A is a commercial power supply, and 6A is a switch.

In this circuit, when motor 1A is overloaded or locked and low rotation speed is detected in circuit 2 3A, the arithmetic circuit operates and after a certain period of time, low rotation speed is detected again or after a certain period of time. If a low rotational speed is detected, immediately activate the overcurrent breaker operation circuit to flow sufficient operating current from point aa to overcurrent breaker 2A, and then
The cut-off operation is performed by a bypass circuit branched from the point.

Note that at this time, the fixed time is longer than the time for one detection.

The time before the electric motor 1A becomes abnormal in the electric motor lock state is set to an arbitrary time according to the electric motor of each cooking appliance.

(Effects of the Invention) As described above, according to the present invention, the cut-off operation is not performed in a temporary overload state or lock when no abnormality occurs in the electric motor, allowing cooking to continue, but in the case of a real overload or lock. This ensures reliable shutoff and prevents burnout of the motor.

[Brief explanation of the drawing]

FIG. 1 is a circuit block diagram of a main part of an electric cooking machine according to an embodiment of the present invention, and FIGS. 2 and 3 are conventional circuit block diagrams of the same main part. 1A is the electric motor, 2A is the overcurrent breaker, 3A is the rotation speed detection/calculation/overcurrent breaker operation circuit, and 4A is the rotation speed detection section.

Claims (1)

[Claims] An electric motor (1A), an overcurrent circuit breaker (2A) connected to this electric motor (1A), and a rotation speed of the electric motor (1A) are detected, and the low rotation speed of the electric motor (1A) is controlled for a certain period of time. A rotation speed detection/calculation/overcurrent function that supplies sufficient operating current to the overcurrent cutter (2A) when the rotation speed continues to be detected or when low rotation speed is detected again after a certain period of time after detection of the low rotation speed. Electric cooking machine equipped with a disconnector operation circuit (3A).