JPS6160664B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bearing temperature detection device for a rotating electrical machine that detects an abnormality in a bearing of a rotating electrical machine at an early stage and prevents the spread of an accident.

A bearing temperature detection device for a water turbine generator will be described below. A conventional bearing temperature detection device of this type was constructed as shown in FIG. That is, in FIG. 1, 1 is a water turbine, 2 is a generator driven by the water turbine 1, 3 is a thrust bearing that supports the generator 2, and 4 is a
5 is a temperature sensing portion provided in the thrust bearing 3 and filled with liquid, and 5 is a temperature sensing portion through which the detected temperature of the temperature sensing portion 4 is transmitted via a conduit 6 filled with liquid, and a contact 51 is closed during operation. It is a Bourdon tube with a pointer that emits an alarm.

In the conventional device configured in this way, when the rotational speed increases, the temperature of the thrust bearing 3 rises, and the liquid in the temperature sensing part 4 expands and passes through the conduit 6 to the Bourdon tube 5.
is compressed and the temperature is indicated, and when the temperature exceeds the set temperature, the alarm contact 51 closes to issue an alarm.

With this conventional method, only the absolute value of temperature is monitored, so it is not only affected by the ambient temperature and bearing cooling water temperature, but also because only the maximum temperature is monitored, bearings are the most prone to accidents. There were drawbacks such as not being able to detect abnormalities during easy startup and stopping, and detection being delayed and an alarm being issued only after the bearing was completely seized and burned out.

The present invention aims to eliminate these drawbacks of the conventional devices, and provides a bearing temperature detection device configured to compare the rate of temperature change dT/dt with levels set corresponding to various operating conditions. It is.

An embodiment of the present invention will be described below based on FIG. 2. That is, in FIG. 2, 7 is a thermocouple that detects the temperature of the bearing attached to the bearing, and 8 is a temperature change that derives the rate of change dT/dt of the temperature signal from the thermocouple 7 introduced through the lead wire 9. rate detection device, 10 is a changeover switch that is automatically switched according to the operating state of the rotating electric machine, such as starting, normal operation, and stopping operation; 11 to 13 are temperature change rates dT/dt in each operating state; Alarm level setters 14 to 16 are used to set standards, comparators 14 to 16 compare the set values of the alarm level setters 11 to 13 and detected values from the temperature change rate detection device 8, and 17 to 19 are used in each operating state. This is an alarm relay that operates when the detected temperature change rate dT/dt exceeds the set value of the alarm bell setters 11 to 13.

FIG. 3 is a diagram illustrating the operation of the above embodiment, and shows how the bearing temperature changes in each operating state, with time on the horizontal axis and bearing temperature on the vertical axis. In the figure, 21 is the bearing temperature, 22 is the time t ₁
Temperature change rate alarm setting level during startup between ~t ₂ , 2
3 is the alarm setting level for the rate of temperature change during normal operation between time points t ₂ and _{t 3} , 24 is the alarm setting level for the rate of temperature change during stop operation between time points t ₃ and _{t 4} , and 25 to 27 are the alarm setting levels for the temperature change rate during normal operation between time points t 3 and t 4, respectively. Indicates abnormal changes in bearing temperature during operating conditions. Note that 28 is the conventional alarm setting level shown in FIG.

In the device configured as described above, when the bearing temperature abnormally changes 25 to 27 exceeding each alarm setting level 22 to 24 in each operating state, the comparator 1
Outputs are derived from alarm relays 17 to 16.
19 is activated to immediately warn of bearing abnormalities and prevent the accident from escalating.

As described above, the bearing temperature detection device for a rotating electric machine according to the present invention derives the rate of change in the bearing temperature of the rotating machine,
By comparing this with the set value of the temperature change rate set according to the operating status of the rotating machine, abnormalities in the bearings are detected. can be prevented.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing a conventional bearing temperature detection device, Fig. 2 is a connection diagram showing main parts of an embodiment of the present invention, and Fig. 3 explains the operation of the embodiment shown in Fig. 2. It is a diagram. In the figure, 3 is a thrust bearing, 7 is a thermocouple, 8 is a temperature change rate detection device, 10 is a changeover switch, 11-
13 is an alarm level setter, 14 to 16 are comparators,
17 to 19 are alarm relays. Note that the same reference numerals in the drawings indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A device for deriving a rate of change in bearing temperature of a rotating electric machine, an output of the temperature change rate deriving device, and a temperature change rate setting value set in accordance with a plurality of operating states of the rotating electric machine. a changeover switch for selectively connecting the temperature change rate derivation device to any of the temperature change rate set value comparison devices according to the operating state of the rotating electrical machine; A bearing temperature detection device for a rotating electrical machine, which detects an abnormal state of the rotating electrical machine based on the output of the device. 2. A bearing temperature detection device for a rotating electric machine according to claim 1, wherein an alarm is issued based on the output of the comparison device.