JPS6016148A - Hydrogen sealing oil supplying device of rotary electric machine - Google Patents

Abstract

PURPOSE:To sufficiently obtain pressure of sealed coil even in the switching to an emergency time by mechanically coupling a sealing oil pump, a normal use AC motor and an emergency DC motor. CONSTITUTION:When an emergency state occurs, the drive force of a normal use AC motor 1 is lost, and the rotation of a sealing oil pump 23 is accordingly dropped, and the exhaust pressure decreases. Then, a pressure switch 6 which is set to the prescribed oil pressure is operated, an emergency DC motor 3 is started, and a sealing oil pump 23 is driven. In this case, since the normal use AC motor 1, the pump 23, and even if the motor 3 are mechanically coupled, the drive force of the motor 1 is lost, the motor 3 is started while rotating by inertia. Accordingly, it reaches the rated rotating speed in a short time. Consequently, the switching time to the emergency time can be shortened, and sealing oil can be sufficiently supplied under the prescribed pressure to a shaft sealing portion 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an improvement in a hydrogen sealing oil supply device employed in a rotating electrical machine such as a hydrogen-cooled turbine generator.

[Background of the invention]

In general, in hydrogen-cooled rotating electric machines, and in particular in hydrogen-cooled turbine generators, in order to prevent hydrogen gas inside the machine from leaking to the outside through the shaft penetration part of the stator, a shaft sealing oil supply system is connected to the shaft penetration part of the stator. It supplies shaft sealing oil at a certain pressure.

This shaft sealing oil supply system, which has been generally adopted in the past, is usually formed as shown in FIG. That is, there is a regular seal oil pump 2 driven by an AC motor 1, and an emergency seal oil pump 4 driven by a DC motor 3 in parallel. Furthermore, a differential pressure regulating valve 5 for adjusting the sealing oil pressure, a pressure switch 6 for switching the driving motors of the regular and emergency sealing oil pumps 2 and 3, a check valve 7, and the like are arranged in the system.

In such a system, the sealing oil discharged from the regular sealing oil pump 2 is adjusted to a predetermined sealing oil pressure by the differential pressure regulating valve 5, and is supplied to the shaft sealing part 9 via the sealed oil supply pipe. If the discharge pressure of the regular seal oil pump 2 decreases due to a loss of power supply 10 or a failure of the AC motor 1 that drives the regular seal oil pump, the pressure switch 6, which is set in advance to a specified oil pressure, is activated. is activated, the emergency seal oil pump 2 is switched to the DC motor 3 side that drives the emergency seal oil pump, and the seal oil pressure is maintained by the emergency seal oil pump 2. Note that 11 in the figure is an emergency power source.

By the way, in such a conventional sealing oil supply system, in an emergency, it takes a certain amount of time from the time when the regular sealing oil pump 2 is stopped until the sealing oil pressure is established in the emergency sealing oil pump 4. The pressure switch 6 is activated and the DC motor 3 is driven, but it takes some time for the DC motor to reach its rated rotational speed.

Therefore, until the sealed oil pressure reaches a specified pressure, the pump discharge pressure decreases, albeit for a short period of time, and there is a risk that hydrogen gas inside the machine may leak to the outside through the stator shaft penetration portion.

[Purpose of the invention]

The present invention has been made with this in mind, and therefore, its object is to provide a highly reliable sealing oil for this type of rotating electric machine that can ensure sufficient sealing oil pressure even when switching the sealing oil pump. To provide feeding equipment.

[Summary of the invention]

That is, the present invention uses a regular sealed oil pump as both a regular and emergency sealed oil pump, and mechanically connects the regular sealed oil pump, an AC motor, and a DC motor, thereby achieving the intended purpose. It was designed to be achieved.

[Embodiments of the invention]

The present invention will be described in detail below based on the illustrated embodiments. FIG. 2 shows one embodiment of the present invention, and the same reference numerals as in FIG. 1 indicate the same parts.

As is clear from the figure, there is a seal oil pump 23 coupled to the seal oil supply pipe 8. This sealed oil pump is used for both regular use and emergency use, and furthermore, this sealed oil pump is mechanically coupled to an AC motor 1 for regular use and a DC motor 3 for emergency use. Therefore, during normal use, the sealing oil pump 23 is driven by the AC motor 1, but since the three are mechanically coupled, the DC motor 3 is of course running idle.

Of course, the opposite is also true. That is, in an emergency, the sealed pump 23 is driven by the DC motor 3, but the AC motor 1 is also idle.

Next, the operation of the sealing oil supply device configured as described above will be explained. First, during normal use, the sealing oil pump 23 is driven by the commonly used AC motor 1, and sealing oil is supplied to the shaft sealing portion 9 through the sealed oil supply pipe 8 at a predetermined pressure. child\
Now, if the power source 10 of the AC motor is lost, that is, if an emergency situation occurs, the driving force of the AC motor 1 will be lost, and the seal oil pump 23 will therefore slow down and its discharge pressure will drop. Then, the pressure switch 6 set to the specified oil pressure is operated, and the emergency DC motor 3 is started to drive the sealing oil pump 23.

In this case, as mentioned before, the AC motor 1, the seal oil pump 23, and the DC motor 3 are mechanically coupled, so
Even if the AC motor 1 loses its driving force, the DC motor 3 will start while it is still rotating due to inertia, which means that the stopped rotating body will be driven to the rated rotation speed as quickly as possible. In other words, we reach .

Therefore, the time required for switching to an emergency situation is shortened, and sealing oil can be sufficiently supplied to the shaft sealing portion 9 at a predetermined pressure.

Next, the sealing oil supply device according to the present invention and the conventional one will be compared in terms of the relationship between the discharge pressure of the sealing oil pump and time in an emergency. FIG. 3 shows the pressure characteristic curve, in which time T is plotted on the horizontal axis and pressure P of the sealing oil is plotted on the vertical axis.

First, to explain the operation of the conventional pump (Fig. 1), if an emergency situation occurs at time To in a regular sealed oil pump that is operated at the discharge pressure PI at the discharge port, the discharge pressure will change according to curve A. It then descends to the operating point P of the pressure switch. When the pressure switch is activated, the emergency seal oil pump is activated and the discharge pressure is restored as shown by curve Bl.

The change in pressure in the shaft sealing portion at this time is shown by a curve C1.

As can be seen from this curve C1, the pressure in the shaft sealing portion drops to below the minimum sealing oil pressure P4.

On the other hand, in the case of an emergency, the present invention
The discharge pressure at the discharge port of the sealed oil pump drops as in the conventional case, as shown by curve A, but the pressure switch is operated to switch to the emergency DC motor, and this DC motor drives the sealed oil pump, resulting in curve B2. Return as follows. That is, the return is performed at an earlier point in time compared to curve B1. The pressure at the shaft sealing part at this time is curve C! Sufficient sealing oil pressure is maintained above the minimum sealing oil pressure P4 as shown in FIG.

In the above explanation, it has been described that the sealed oil pump, the regular AC motor, and the emergency DC motor are mechanically coupled. It is possible to combine the products, but it would also be possible to incorporate the three or the king on the same axis in advance and combine the two products. Alternatively, electromagnetic couplings may be arranged between the three, respectively, and the coupling may be performed as necessary. Particularly in this case, an electric motor whose power supply is suddenly lost, for example, an AC motor when AC power supply is suddenly lost, is not idling, so it is effective from the point of view of protecting the motor.

〔Effect of the invention〕

As explained above, according to the device of the present invention, one sealed oil pump can be used both as a regular and emergency sealed oil pump, and this sealed oil pump, a regular AC motor, and an emergency DC motor can be combined. Since the three components are mechanically connected, the sealed oil pump will rotate with some degree of inertia when the AC power supply is lost and when the AC motor is stopped and switched to the emergency DC motor. Since the sealing oil pump is driven by a DC motor, the time required for the pump to return to its rated rotational speed is sufficiently shortened, and therefore sufficient sealing oil pressure can be ensured even during emergency switching.

[Brief explanation of the drawing]

Fig. 1 is a system diagram showing the main parts of a conventional hydrogen sealing oil supply device, Fig. 2 is a system diagram showing the main parts of the hydrogen sealing oil supply device of the present invention, and Fig. 3 is a sealing oil system in an emergency situation. It is a seal oil pressure characteristic diagram showing the relationship between the seal oil pressure and time. DESCRIPTION OF SYMBOLS 1... AC motor, 3... DC motor, 6... Pressure switch, 8... Sealed oil supply pipe, 9... Shaft sealing part,
23...Secret number J5 I'o rl τ

Claims (1)

[Claims] 1. A sealing oil supply system that supplies shaft sealing oil to the shaft sealing portion by a sealing oil pump, an AC motor that constantly drives the sealing oil pump, and an AC motor that drives the sealing oil pump in an emergency. In a hydrogen sealing oil supply device for a rotating electric machine, the hydrogen sealing oil supply device is equipped with a DC motor and is configured to supply shaft sealing oil to the shaft sealing part.
A hydrogen sealing oil supply device for a rotating electric machine, characterized in that the sealing oil pump, an AC motor, and a DC motor are mechanically coupled. 2. The hydrogen-sealing oil supply device for a rotating electric machine as set forth in claim 1, wherein the mechanical coupling of the three components is performed through electromagnetic force coupling.