JPS5989550A - Rotary electric machine - Google Patents

Abstract

PURPOSE:To prevent the local heating in a rotary electric machine by interlocking internal pressure reducing means with a temperature sensor which is provided at a part in the machine. CONSTITUTION:When a local heat is generated at the prescribed part in a rotary electric machine, a temperature sensor 4 outputs a detection signal, which is transmitted through a signal cable 4a to a pump driving motor 3a and a valve 3d. Thus, the pump 3a starts operating, the valve 3d becomes open state, air is fed through an air pipe 3c into the machine, thereby enhancing the pneumatic pressure in the machine. Simultaneously upon starting of the pump 3a, a pump 2a is stopped by an interlock signal which is transmitted through interlocking wirings 6. When the detected value of the sensor 4 decreases lower than the prescribed value, the pump 3a is stopped, the valve 3d is closed, and the pump 2a is restarted.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to improvements in rotating electrical machines, and particularly relates to improvements in rotating electrical machines that reduce the internal pressure of the rotating electrical machine and reduce the windage loss of the rotor. It is something.

[Prior art]

Conventionally, commonly used rotating electric machines circulate cooling air inside the machine to cool the rotating electric machine.
In a rotating electric machine that is cooled by circulating cooling air, friction loss occurs due to the rotating body rotating in contact with the cooling air, and ventilation loss occurs due to the kinetic behavior of the cooling air. These losses decrease as the rotation speed increases.
The larger the capacity (output), the more. This loss, so-called mechanical loss, impedes the efficiency improvement of rotating electric machines and must be reduced. In order to reduce this, a method (hereinafter referred to as a "depressurization method") is adopted in which the pressure of the air inside the rotating electric machine (the space where the rotating body contacts the air) is reduced. This is based on the principle that ventilation friction loss is proportional to air pressure, i.e.: W, oc, p...
(1) W: Ventilation friction loss p: Based on air pressure.

However, the surface heat transfer coefficient decreases with decreasing air pressure. That is, in general, if the surface heat transfer coefficient is α, the Reynozzle number is Ro, and the Prandtl number is P, then αoc R1@'・"X P t "
−−−−・−・・・The relationship (2) is established. Here, if the shape of the ventilation passage is the same in the rotating electric machine, even if the air pressure P is reduced, the Prandtl number P and the wind speed V remain unchanged, so R, cx: PV, so in the end αoc pool...・・・・・・
・(3) becomes. That is, the surface heat transfer coefficient α decreases in proportion to the air pressure to the 0.8th power.

As mentioned above, the loss can be reduced by reducing the air pressure P, but the cooling effect will also be reduced.1.
To compensate for this, measures are taken such as directly cooling the windings, cores, etc. with a cooling medium such as water or oil.

However, even if the above measures are taken, the tips of the core teeth, that is, the parts that are in close proximity to the air, such as between adjacent windings of the core, the longitudinal ends of the core, and the back of the core, cannot be directly cooled by water. Because it is difficult to cool down with other cooling means, there is a risk of local overheating depending on the operating conditions (for example, phase advance operation). It is thought that this problem can be solved by arranging cooling pipes for direct water cooling to the relevant part, but this is usually not possible due to dimensional constraints and reduced core strength. be.

[Purpose of the invention]

The present invention has been made to solve this problem, and the purpose is to fully prevent local overheating inside the rotating electrical machine under certain specific operating conditions. We provide various kinds of rotating electric machines.

[Summary of the invention]

That is, the present invention provides a rotating electrical machine in which a rotor rotates in low-pressure air, and a temperature sensor is provided in a part of the interior of the rotating electrical machine, and when the temperature sensor indicates a temperature equal to or higher than a predetermined temperature value, An air supply means for supplying air into the cabin is provided, and when the temperature sensor indicates that the temperature is below a predetermined value, the cabin pressure reducing unit and the temperature sensor are linked to operate the cabin pressure reducing unit. It was designed to achieve the objectives of the period.

[Embodiments of the invention]

The present invention will be described in detail below based on the illustrated embodiments. In FIG. 1, the rotating electric machine is shown diagrammatically. That is, in this figure, reference numeral 1 denotes a main body of a rotating electrical machine, within which there is a stator 1a having windings and an iron core, and a rotor 1b rotating within the stator. An outer frame IC is provided on the outer periphery of the stator 1a and is formed to support the stator and isolate the inside of the machine from outside air.

Reference numeral 2 denotes an in-machine pressure reducing means, and this in-machine pressure reducing means includes an evacuation pump 2a, a motor 2b for driving the pump, and a pipe 2C connecting the evacuation pump and the inside of the machine.

3 is an air supply means, and this air supply means is equipped with an air supply pump 3a, an air supply pump driving motor 3b, and a pipe 3C connecting the air supply pump and the inside of the machine. 3d is a valve provided in the middle of the pipe 3C.

Reference numeral 4 provided in a part of the interior of the machine indicates a temperature sensor, and this temperature sensor operates the air supply means 3 and the interior pressure reduction means 2, respectively, according to the indicated temperature.

Fi! Reference numeral 15 indicates a power source for the pump driving motor 2b and the air supply pump driving motor 3b.

In the rotating electric machine configured in this manner, the inside of the machine is always maintained in a reduced pressure state by the machine internal pressure reducing means 2. At the same time, although not shown in the figure, the windings and core are cooled by a pure water supply device. The temperature sensor 4 has a function of detecting the temperature near the part where there is a risk of local overheating, and the detection signal is sent to the pump drive motor 3b via the signal cable 4a.
and is transmitted to the pulp 3d, which starts the motor 3b and opens the normally closed pulp 3d.

Next, the functions of the above configuration will be explained. If local overheating occurs in a certain part of the rotating electric machine due to some operating conditions,
The temperature sensor 4, which is preset to operate when the temperature exceeds a certain level, outputs a detection signal, and the signal cable 4a
The pump drive motor 3b1? and is transmitted to the pulp 3d. As a result, the pump 3a starts operating and the pulp 3d becomes open, and air is rotated 1! through the air pipe 3C. Send it inside the aircraft to increase the air pressure inside the aircraft.

The pump 2a is stopped by an interlock signal transmitted via the interlock wiring 6 at the same time as the pump 3a is started.

The above function increases the air pressure inside the rotating electric machine, so
The surface heat transfer coefficient increases and the temperature of the locally overheated area decreases, thus achieving the desired purpose. When the detected value by the temperature sensor falls below a predetermined value, the pump 3a stops, the pulp 3d becomes closed, and the pump 2a restarts.

FIG. 2 shows a modification of the present invention, and the difference between this diagram and FIG. 1 is that the air outlet of the air supply pipe 3C is arranged near the local overheating section. As a result, in addition to the effect of increasing the cooling effect due to the increase in air pressure, the locally overheated portion can realize an even greater effect of reducing the temperature rise due to the increase in the cooling effect due to the local increase in the air flow velocity.

〔Effect of the invention〕

As described above, the present invention includes a temperature sensor provided in a part of the inside of the rotating electric machine, and an air supply means that supplies air into the machine when the temperature sensor indicates a predetermined temperature value or higher. Since the in-machine pressure reducing means and the temperature sensor are linked so that the in-machine pressure reducing means is activated when the sensor indicates that the temperature is below a predetermined value, local overheating may occur under certain operating conditions. However, this can be fully prevented.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing one embodiment of the rotating electrical machine of the present invention, Fig. 2 is a diagram showing an embodiment of the rotating electrical machine of the present invention;
The figure is a diagram showing another embodiment of the rotating electrical machine of the present invention. 1...Rotating electric machine main body, 1a...Stator, 1b...
Rotor, IC...Outer frame, 2...In-machine pressure reduction means, 3
... Air supply means, 4... Temperature sensor. No./mouth

Claims (1)

[Claims] 1. A stator including windings and an iron core, a rotor rotating within the stator, supporting the stator, covering the entire stator, and isolating the interior of the machine from outside air. A rotating electrical machine is provided with an outer frame formed as shown in FIG. A temperature sensor is provided in a part, and an air supply means is provided to supply air into the cabin when the temperature sensor indicates a temperature higher than a predetermined temperature value, and when the temperature sensor indicates a temperature higher than the predetermined temperature value, the pressure inside the plane is reduced. A rotating electric machine characterized in that an internal pressure reducing means and a temperature sensor are linked to operate the means. 2. The temperature sensor is arranged between adjacent windings of the stator core, and the air supply section of the air supply means is also arranged near between the adjacent windings of the stator core. A rotating electric machine according to claim 1.