JPS635440Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drooping correction circuit during acceleration and deceleration of a tandem rolling mill that improves responsiveness of acceleration and deceleration.

Fig. 1 shows an example of a speed control device for a tandem rolling mill, which includes a speed command device (MRH) 1 that specifies the required speed, and a speed command for each stand based on the commands from the device 1. A stand speed command device (SSRH) 2, a drooping setting device 3 that sets the amount of drooping, a current transformer 5 that detects the current flowing to the mill motor 4 that drives the work roll WL of the rolling mill, and the current transformer an amplifier 6 for amplifying the output of the amplifier 5; a multiplier 7 for multiplying the output signal of the amplifier 6 by the output signal of the drooping setting device 3;
Consists of a speed control device (ASR) 8 that outputs a speed control command based on the output signal of the multiplier 7 and the output signal of the SSRH 2, and a thyristor 9 that drives the mill motor 4 based on the output signal of the device 8. be done. Each of the work rolls of the plurality of stands is provided with a control device as shown in FIG.

In the above configuration, the overall speed command is
It is given by MRH1, and commands for each stand are given by SSRH2 in proportion to the settings.
The speed of each stand is controlled according to the commands of SSRH2. ASR based on this SSRH2 output signal
8 drives the mill motor 4 via a thyristor 9. On the other hand, a drooping circuit is provided to absorb load fluctuations and prevent breakage.

The drooping circuit detects the load fluctuation of the mill motor 4 using a current transformer 5, and multiplies the amplified current change value by the drooping setting value from the drooping setting device 3 using a multiplier 7 to obtain a change value commensurate with the speed. is calculated and sent to ASR8 to increase or decrease the speed. However, since the detected current change is an absolute value, the drooping circuit also operates depending on the current used for acceleration/deceleration.
In addition, the deceleration current causes the motor to operate in the direction of increasing the speed, thereby functioning to delay deceleration. For this reason, the drooping circuit causes a delay in acceleration/deceleration, that is,
There is an inconvenience that the response of the mill motor 4 to the speed command is delayed.

An object of the present invention is to provide a drooping correction circuit during acceleration and deceleration of a tandem rolling mill, which eliminates speed response delay during acceleration and deceleration due to drooping.

The present invention eliminates the speed correction from the drooping circuit based on acceleration/deceleration current, so that even during acceleration/deceleration, drooping functions only on the current due to load fluctuation, and eliminates the delay in speed response during acceleration/deceleration due to drooping. This is what I did.

FIG. 2 shows an embodiment of the present invention,
Components that are the same as those shown in FIG.
Characteristic calculator 10 that differentiates the output signal of SSRH2
The configuration differs from the configuration shown in FIG. 1 in that it includes an adder 11 that adds the output signal of the amplifier 6 and the output signal of the feature calculation unit 10 and outputs the result to the multiplier 7.

In the above configuration, the command of SSRH2 is divided by the characteristic calculation unit 10, and the value corresponding to this acceleration/deceleration current is subtracted by the adder 11 from the load current value output from the amplifier 6. It is possible to make drooping always operate only in response to load fluctuations, regardless of the load fluctuation.

As is clear from the above, according to the present invention, speed correction is not included in drooping during acceleration and deceleration, so response delay during acceleration and deceleration is eliminated.
The occurrence of off-gauge can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a conventional drooping correction circuit used in a speed control device, and FIG. 2 is a circuit diagram showing an embodiment of the present invention. 1... Speed command circuit (MRH), 2... Stand speed command device (SSRH), 3... Drooping setting device, 4... Mill motor, 5... Current transformer, 6...
...Amplifier, 7... Multiplier, 8... Speed control device (ASR), 9... Thyristor, 10... Signal calculation circuit, 11... Adder.

Claims (1)

[Scope of utility model registration request] Drooping is added for the purpose of absorbing load fluctuations to the speed control device that controls the speed of the mill motor that drives the work rolls of the stand that makes up the tandem rolling mill while feeding back the detected load current value based on the stand speed command. In the drooping circuit that provides the characteristics, there is a characteristic calculator that divides the acceleration/deceleration command and calculates a current value equivalent to the acceleration/deceleration, and subtracts the detected load current value from the output signal of the characteristic calculator, and calculates the difference. A drooping correction circuit for accelerating and decelerating a tandem rolling mill, comprising a drooping signal generator that multiplies the value by a drooping set value and outputs a drooping signal.