JPS6211330U - - Google Patents

Description

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing a motor overload detection device according to an embodiment of this invention, Fig. 2 is a flowchart showing the operation of this embodiment, and Fig. 3 is a detection of drive power supply stop time and motor load correction. FIG. 4 is a block diagram showing a conventional motor overload detection device, and FIG. 5 is a flowchart showing a method for detecting motor overload when power is turned on. In the figure, 1 is an electric motor, 2 is a drive power supply device,
3 is an overload state detection calculation means, 3-3 is a load calculation circuit, 3-3a is load state data, 4 is a correction amount calculation means, 4-2a is load correction data, 4-3 is a time measurement circuit, 4- 7 is a data memory, 4-8 is a time constant holding memory, and 4-10 is a correction circuit. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] The load status data of the motor is converted into a heat generation temperature value, and when the heat generation temperature value exceeds the heat generation temperature setting value, it is determined as an overload condition and a detection signal is output to stop the supply of drive power to the motor. an overload state detection calculation means that retains the heat generation temperature value at the time of the stop, and calculates the load state data when the drive power is turned on again after a predetermined period of time has elapsed based on the heat generation temperature value held at the time of the stop. In an overload detection device for an electric motor, the motor overload detection device is equipped with a correction amount calculation means for correcting a later heat generation temperature value and setting it as initial data. A memory, a time constant holding memory that stores multiple thermal time constants unique to each motor, a time measurement circuit that measures the elapsed time from when the drive power is stopped until it is turned on again, and a temperature value of the heat generated when the power is turned on again. a correction circuit that calculates based on the heat generation temperature value, thermal time constant, and elapsed time read out from the data memory, time constant holding memory, and time measurement circuit, and sets it as initial data to the overload state detection calculation means; An overload detection device for an electric motor, characterized by comprising: