JPH04353202A - Main turbine control device - Google Patents

Abstract

PURPOSE:To obtain a main turbine control device possible to precisely control an idle point of a propeller due to coasting of a hull at 1/10 RPM or less. CONSTITUTION:Pulse from a pulse generator 15 in response to detection of a proximity switch 14 for the purpose of detecting ridges of teeth in a speed reducer 13 is counted by a pulse counter 16. This counted value is converted to an analogic signal proportional to revolution speed of a main shaft 5 by a F/A converter 17, and a changeover switch 18 is changed over to the F/A converter 17 side with a command from a revolution speed monitor 8 when the revolution speed monitor 8 watching revolution speed of a tachogenerator 7 detects a specified low revolution speed. Therefore, a lowering of precision of the tachogenerator 7 at the time of low revolution speed can be compensated, and low speed control after charging in braking steam can be surely performed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a main turbine control device for controlling the rotation of a main turbine engine that rotates a propulsion propeller of a ship.

0002

2 is a block diagram showing a conventional main turbine control system. In FIG. 1, 1 is a main turbine as a controlled object, 2 is a forward governor that supplies forward steam to the main turbine 1, and 3 is a forward governor that supplies forward steam to the main turbine 1. A reverse governor provides reverse steam to the main turbine 1; 4 is a reducer that reduces the rotation of the main turbine 1; 5 is a main shaft that transmits the reduced rotation; 6 is the main shaft 5
7 is a tacho generator that detects the rotation speed of the main shaft 5 and outputs a main shaft rotation feedback signal B; 8 is a rotation speed monitor that monitors the rotation speed indicated by the main shaft rotation feedback signal B; 9 is a rotation speed monitor; This switch is controlled by the output of the rotation speed monitor 8.

Reference numeral 10 denotes a speed specifying lever that outputs a speed command signal A, and 11 a rotation speed control circuit that outputs an error signal C based on the speed command signal A and the spindle rotation feedback signal B obtained via the switch 9. , 12 is a forward governor control circuit that controls the forward governor 2 based on the speed command signal A, error signal C, and a feedback signal from the forward governor 2; 13 is a forward governor control circuit that controls the forward governor 2 based on the speed command signal A, the error signal C, and the feedback signal from the reverse governor 3; This is a reverse governor control circuit that controls the reverse governor 3 based on the feedback signal.

Next, the operation will be explained. When the ship is moving forward, the voltage of the speed command signal A given by the speed command lever 10 is +, and the voltage of the main shaft rotation feedback signal B detected by the tacho generator 7 attached to the main shaft 5 is -. The rotation speed control circuit 11 opens and closes the forward governor 2 based on both signals A and B so that the error signal C becomes C=A+B=0, thereby controlling the amount of steam input to the main turbine 1.

When a stop command is issued by the speed command lever 10 while the ship is moving forward, the speed command signal A becomes 0, but since the main shaft 5 is rotating in the forward direction, the rotation speed control circuit 1
The voltage of the error signal C from 1 becomes -. This error signal C
rotates the forward governor 2 in the closing direction via the forward governor control circuit 12 to fully close it. As a result, the forward steam that has been input to the main turbine 1 is cut off. However, since the hull is coasting, the main shaft 5 is idled by the propeller 6, and a negative voltage is still generated in the main shaft rotation feedback signal B. Therefore, the voltage of the error signal C maintains a negative value. are doing. This error signal C passes through the reverse governor control circuit 13 and rotates the reverse governor 3 in the opening direction. As a result, reverse steam, that is, brake steam, is supplied to the main turbine 1 in the direction in which the rotation of the main shaft 5 is reversed.

When the rotation of the main shaft 5 gradually decreases due to this injection of brake steam, the error signal C from the rotation speed control circuit 11 also decreases in proportion to the rotation of the main shaft 5, causing the reverse governor 3 to rotate in the closing direction. and reduce the amount of brake steam input. When the rotation of the spindle 5 drops to 5 RPM, the rotation speed monitor 9 turns off the switch 9 and cuts the spindle rotation feedback signal B. As a result, the error signal C becomes 0, the reverse governor 3 is fully closed, and the brake steam input to the main engine turbine 1 is cut off.

After the brake steam is cut, when the main shaft 5 reaches 10 RPM or more due to free rotation of the propeller 6, the rotation speed monitor 8 turns on the switch 9, and the main shaft rotation feedback signal B causes the reverse governor 3 to rotate in the opening direction again. Then, brake steam is supplied to the main turbine 1 again. After the brake steam is input, when the rotation of the main shaft 5 drops to 5 RPM, the rotation speed monitor 8 turns off the switch 9, cuts the main shaft rotation feedback signal B, fully closes the reverse governor 3, and cuts off the brake steam. By repeatedly opening and closing the reverse governor 3 as described above, the rotation of the main shaft 5 is controlled to be 10 RPM or less when a stop command is issued.

[0008]

[Problems to be Solved by the Invention] The conventional main turbine control device is configured as described above, and uses the tacho generator 7 to detect the rotation of the main shaft 5. Therefore, in the low rotation range of the main shaft 5, the main shaft If the detection accuracy of the rotation of the propeller 5 deteriorates and control is performed to a low rotation, the propeller 6 may rotate in the opposite direction, causing problems such as the inability to completely stop the free rotation of the propeller 6 due to coasting of the hull.

The present invention was made in order to solve the above-mentioned problems, and its purpose is to provide a main shaft turbine control device that can control the idle rotation of the propeller due to coasting of the ship to 1/10 RPM or less. do.

0010

[Means for Solving the Problems] The main turbine control device according to the present invention detects the rotation of the main shaft by a proximity switch attached to the reducer of the main turbine, and detects the rotation of the main shaft by a proximity switch attached to the reducer of the main turbine. etc., to convert the low-speed rotation of the spindle, for example, 2 RPM or less, into a voltage signal, which is used as a spindle rotation feedback signal.

[0011]

[Operation] The main turbine control device according to the present invention improves the accuracy of detecting the rotation of the main shaft at 2 RPM or less, and can finely control the amount of brake steam input.

0012

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, parts that are the same as those in FIG. 2 are given the same reference numerals, and explanations thereof will be omitted. In FIG. 1, 14 is a reducer 13
15 is a pulse generator that outputs a pulse signal of a predetermined frequency; 16 is a proximity switch provided near the teeth of the gear;
17 is an F/A converter that converts the count value of the pulse counter 16 into an analog signal; 18 is a spindle rotation feedback signal from the tacho generator 7; This is a changeover switch for switching between B and the output signal of the F/A converter 17 using the rotation speed monitor 8.

Next, the operation will be explained. A proximity switch 14 attached to the reducer 4 detects, for example, optically the time from one peak of the gear of the reducer 4 to the next peak. On the other hand, the pulse generator 15 constantly oscillates a pulse signal of a constant frequency and sends it to the pulse counter 16. The pulse counter 16 detects the speed reducer 13 detected by the proximity switch 14.
The number of pulses from the pulse generator 15 is counted during the time from one gear peak to the next gear peak and is sent to the F/A converter 17. The F/A converter 17 converts the number of pulses from the pulse counter 16 into an analog signal corresponding to 2 to 1/10 RPM of the main shaft 5 and outputs the analog signal.

When a stop command is issued by the speed command lever 10 while the ship is moving forward, the speed command signal A becomes 0, but since the main shaft 5 is rotating, the main shaft rotation feedback signal B obtained from the tacho generator 7 A negative voltage is generated. Therefore, the error signal C from the rotation control circuit 11
Since C=A+B, it becomes a - voltage. This error signal C
The forward governor 2 is fully closed and the reverse governor 3 is opened to supply brake steam to the main turbine 1.

As the rotation of the main shaft 5 gradually decreases due to this injection of brake steam, the error signal C also decreases in proportion to the rotation of the main shaft 5, causing the reverse governor 3 to rotate in the closing direction.
Reduce the amount of brake steam input. When the rotation of the spindle 5 becomes 2 RPM or less, the output signal of the tachogenerator 7 becomes unstable, so the changeover switch 18 is switched to the F/A converter 17 side by a command from the rotation speed monitor 8, and the spindle rotation feedback signal B is used by switching to the signal from the F/A converter 17.

As described above, since detection of low-speed rotation after inputting brake steam is carried out based on the count value of the pulse signal corresponding to the detection of the proximity switch 14, the detection accuracy of low-speed rotation is increased, and the It becomes possible to reliably control the rotation of the main shaft 5 to 1/10 RPM or less after steam is introduced.

[0017]

As described above, according to the present invention, pulses are counted by the operation of a proximity switch provided in a low-speed machine in the spindle rotation feedback signal in the low rotation range of the spindle, and an analog signal corresponding to the number of pulses is generated. Since the configuration uses
It is now possible to reduce the amount of propeller rotation caused by coasting of the ship by 1
The effect of reliably suppressing the speed to /10 RPM or less can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a main turbine control device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional main turbine control device.

[Explanation of symbols]

1 Main engine turbine 2 Forward governor 3 Reverse governor 5 Main shaft 6 Propulsion propeller 8 Rotation speed monitor 13　Reducer 14 Proximity switch 16 Pulse counter 17 F/A converter 18 Selector switch A Speed command signal B Spindle rotation feedback signal C Error signal

Claims (1)

[Claims] Claim 1: The rotation of the main turbine is decelerated by a speed reducer and transmitted to the main shaft provided with the propulsion propeller, and the rotation of the main shaft is detected in response to an error signal obtained from a main shaft rotation feedback signal and a speed command signal. In the main turbine control device, the main turbine control device is configured to control a forward governor and a reverse governor that input steam to the main turbine, a proximity switch provided on the reduction gear for detecting rotation in a predetermined low speed rotation region; a pulse counter that counts pulse signals according to the output of the proximity switch; an F/A converter that converts the count value of the pulse counter into an analog signal; a rotation speed monitor that monitors the rotation speed of the main shaft; A main turbine control device comprising: a changeover switch that switches the main shaft rotation feedback signal to the output of the F/A converter when the main shaft rotation speed reaches a predetermined low speed rotation.