JPH04320744A - Abnormal state sensing device for ventilator - Google Patents

Abstract

PURPOSE:To enable a rapid stopping of supplying of electrical power to be carried out in the case that some abnormal states such as an over-load and a locked state and the like are produced in a capacitor induction electric motor for use in driving a fan. CONSTITUTION:A relay coil 19 for use in sensing an inter-terminal voltage of an auxiliary winding 17, for example, in the auxiliary winding 17 or a capacitor 18 of a capacitor induction electric motor 14 is provided. As the inter- terminal voltage of the auxiliary winding 17 is lowered than a value of range of application of a fan 21, a supplying of electricity for the electric motor 14 is stopped with a relay switch 13. For example, as the electric motor 14 is locked, the inter-terminal voltage of the auxiliary winding 17 is decreased, this state is detected by the relay coil 19 to operate the relay switch 13 and to shut off a power supply. It prevents positively a high current from flowing to the windings 15 and 17 and at the same time it may operate an informing lamp 16.

Description

[Detailed description of the invention]

[Object of the invention]

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abnormality detection device for a ventilation system having a capacitor induction motor consisting of a main winding, an auxiliary winding, and a capacitor for rotating a fan.

0003

2. Description of the Related Art A single-phase capacitor induction motor 1 for driving a fan installed in a conventional ventilation system, such as a duct ventilation fan, has a main winding 2 connected between the output terminals of an AC power source 5, as shown in FIG. At the same time, the auxiliary winding 3 and the capacitor 4
The electrical configuration consists of connecting series circuits. Further, the main winding 2 and the auxiliary winding 3 are respectively provided with temperature detection detectors 6 and 7.
Alternatively, a circuit opener 8 is interposed in the power supply path so that the power supply from the AC power source 5 is stopped when the detected temperature of either of the AC power supplies 7 and 7 reaches a predetermined temperature.

With such a configuration, for example, when the load on the fan or rotor increases and a large current flows through the main winding 2 or the auxiliary winding 3, the temperature gradually decreases due to power loss due to the resistance component. It continues to rise. When the predetermined temperature is reached, the detector 6 or 7 detects this and operates the circuit opener 8 to stop the power supply. Therefore, the electric motor 1 is protected from deterioration or failure due to overheating.

[0005]

However, in the conventional structure as described above, when the rotor of the capacitor induction motor 1 is locked and a large current flows through the main winding 2, the winding Since the temperature of the wire gradually rises after entering the locked state, it takes time to reach the predetermined temperature detected by the detector 6 or 7.

[0006] Therefore, until the power supply is stopped by the circuit opener 8, a considerable amount of lock current flows through the winding, and the resulting heat generation deteriorates the insulation of the winding and shortens its life. Ta. Furthermore, in the case of the above-mentioned type that detects temperature, accurate detection cannot be performed because the influence of fluctuations in ambient temperature is large.

[0007] As described above, even if the power supply is stopped by the circuit opener 8, the duct ventilation fan is normally installed in the ceiling, so there is a problem that the user does not notice it.

[0008] Incidentally, there is a technique disclosed in Japanese Utility Model Publication No. 7729/1983 as a technique capable of solving the problems of the above-mentioned conventional structure.

[0009] This motor connects a generator directly to a capacitor induction motor, causes the generator to generate a voltage proportional to the number of revolutions, and uses the generated voltage to turn on and off a relay, thereby reducing the number of revolutions. When a failure occurs, a relay switch is used to cut off the power to the motor and operate an abnormality display device.

However, since the device disclosed in the publication uses an expensive generator, it is too expensive as an abnormality detection device for a ventilation fan, and there is a problem in its feasibility.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to be able to promptly detect and disconnect power from a capacitor induction motor used to drive a fan, and to notify the user of the occurrence of an abnormality. To provide an abnormality detection device for a ventilation system which can be manufactured at low cost.

[Configuration of the invention]

[0013]

[Means for Solving the Problems] An abnormality detection device for a ventilation system according to the present invention is provided in a ventilation system having a capacitor induction motor consisting of a main winding, an auxiliary winding, and a capacitor for rotationally driving a fan. Voltage detecting means for detecting the voltage between the terminals of some or all of the lines or the voltage between the terminals of the capacitor is provided, and when the detected voltage of the voltage detecting means falls below a value within the applicable range of the fan, the power source of the motor is turned off. It is characterized in that it is provided with an open circuit control means that substantially shuts off the circuit and operates the notification means.

[0014]

[Operation] According to the abnormality detection device for a ventilation system of the present invention, when the rotation speed of the capacitor induction motor falls below the applicable range of the fan, the voltage between the terminals detected by the voltage detection means also becomes lower than the value within the applicable range of the fan. Since the voltage also decreases, the circuit opening control means substantially cuts off the power to the electric motor and operates the notification means.

Therefore, when the capacitor induction motor becomes overloaded or a locking accident occurs in the capacitor induction motor, the power supply is immediately cut off, ventilation operation is stopped, and a notification operation is performed.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the present invention is applied to a duct ventilation fan will be described below with reference to FIGS. 1 to 3.

In FIG. 1 schematically showing the electrical configuration, one end 11a of an AC power source 11 is connected via a power switch 12 to a movable contact c of a relay switch 13, which is a circuit-opening control means. Normally open side fixed contact piece a of relay switch 13
is connected to the other end 11b of the AC power supply 11 via the main winding 15 of the capacitor induction motor 14. A normally closed fixed contact b of the relay switch 13 is connected to the other end 11b of the AC power source 11 via a notification lamp 16 serving as notification means.

Auxiliary winding 17 of capacitor induction motor 14
A series circuit of the capacitor 18 and the capacitor 18 is connected in parallel to the main winding 15. A relay coil 19 serving as voltage detection means is connected in parallel to the auxiliary winding 17. This relay coil 19 operates the relay switch 13 described above in a state where a voltage of a predetermined value or more is applied between both terminals. A positive temperature characteristic resistance element 20 is provided between the normally open side fixed contact piece a and the movable contact piece c of the relay switch 13.
is connected. This positive temperature characteristic resistance element 20 has positive temperature characteristics, and its resistance value increases, for example, when the temperature rises due to self-heating due to energization.

Although not shown, the capacitor induction motor 14 is installed in an outer casing arranged in the ceiling, and its rotating shaft is connected to a spiral casing arranged inside the outer casing. It is connected to a centrifugal multi-blade fan 21 which is a radial fan.

Next, regarding the operation of this embodiment, FIGS. 2 and 3 will be explained.
2, the motor torque curve TM of the capacitor induction motor 14, the fan torque curves TFA and TFB of the centrifugal multi-blade fan 21, and the auxiliary winding 1 are shown in FIG.
The terminal voltage V of the centrifugal multi-blade fan 2 is shown in FIG.
The air volume vs. static pressure characteristics of No. 1 are shown.

In the device configured as described above, when the power switch 12 is turned on, the relay switch 13 is turned on between the movable contact piece c and the normally closed side fixed contact piece b, so the notification lamp 16 is turned on. At the same time, the capacitor induction motor 14 is energized via the positive temperature characteristic resistance element 20. At this time, since the positive temperature characteristic resistance element 20 is in a low resistance state, a substantially rated voltage is applied to the capacitor induction motor 14, and it rotates in a normal operating state.

When the rotational speed of the capacitor induction motor 14 reaches a predetermined rotational speed, the voltage between the terminals of the auxiliary winding 17 increases and becomes sufficient voltage to excite the relay coil 19, thereby operating the relay switch 13. let That is, the normally open fixed contact piece a and the movable contact piece c of the relay switch 13 are closed, the notification lamp 16 is turned off, and the capacitor induction that was energized via the positive temperature characteristic resistance element 20 is turned off. The motor 14 is now energized via the relay switch 13 and is in steady state or coverage.

In this case, the centrifugal multi-blade fan 21 has an air volume-static pressure characteristic as shown in FIG. will be determined. Therefore, FIG. 3 shows the applicable range of the centrifugal multi-blade fan 21, and A shows the maximum air volume.
The points are the motor torque curve TM and fan torque curve T in Figure 2.
It is the intersection point C with FA, and the point B showing the maximum static pressure is the intersection point D between the motor torque curve TM and the fan torque curve TFB in FIG. The rotation speeds are Ra and Rb, and the voltages between the terminals of the respective auxiliary windings 17 are Va and Vb.

[0024]Therefore, there is no problem when the centrifugal multi-blade fan 14 is within the applicable range as described above, but if the capacitor induction motor 14 becomes, for example, in a locked state and the rotation speed becomes zero, , the voltage between the terminals of the auxiliary winding 17 becomes lower than the voltage Va (see FIG. 2). As a result, the voltage applied between both terminals of the relay coil 19 becomes lower than the operating voltage, so that the operating state of the relay switch 13 is released. That is, the notification lamp 16 becomes energized and lit to notify the abnormal state, and the capacitor induction motor 14
The current is applied through the positive temperature characteristic resistance element 20.

However, since the capacitor induction motor 14 is in the locked state as described above, the main winding 15 and the auxiliary winding 17 are energized through the positive temperature characteristic resistance element 20, but are not rotating. Positive temperature characteristic resistance element 20
A current flows through. As a result, the positive temperature characteristic resistance element 20
Since self-heating occurs and the resistance value increases, the power supply to the capacitor induction motor 14 is greatly restricted, resulting in a state substantially equivalent to being cut off. In this state, the resistance value of the positive temperature characteristic resistance element 20 remains at a steady state with high resistance, so that the capacitor induction motor 14
The power supply cutoff state is maintained.

According to this embodiment, the following effects can be obtained.

That is, if a locking accident occurs in the capacitor induction motor 14, the main winding 15 and the auxiliary winding 17
The lock current to the winding is cut off, and the lock current does not continue to flow through the winding, causing insulation deterioration and shortening its life. Further, since the circuit is cut off based on the voltage between the terminals of the auxiliary winding 17 without being affected by the ambient temperature, the abnormal state can be detected more accurately and the operation can be performed, and reliability can be improved.

In this case, since the duct ventilation fan is installed in the ceiling, even if the centrifugal multi-blade fan 21 falls outside the applicable range due to construction errors, the notification lamp 16 will notify you of this. You can find out quickly.

Moreover, a relay coil 19 is provided as a voltage detection means, and a relay switch 13 is provided as a circuit opening control means.
Compared to the case where a generator is installed,
It can be manufactured at low cost and has extremely high feasibility.

FIG. 4 shows a second embodiment of the present invention, which differs from the first embodiment in that a starting switch 22 is provided in place of the positive temperature characteristic resistance element 20. It is. That is, when the start switch 22 is turned on, it is kept in the on state for 1 to 2 seconds and then turned off.

In other words, the starting switch 22 functions as the positive temperature characteristic resistance element 20 in the first embodiment.
Start switch 22 when starting capacitor induction motor 14
When turned on, the capacitor induction motor 14 starts rotating and is energized for 1 to 2 seconds until its rotational speed reaches the applicable range.After this, when the relay switch 13 is operated, the starting switch 22 is turned off. This is what has become.

Therefore, in this second embodiment as well, substantially the same effects as in the first embodiment can be obtained.

FIG. 5 shows a third embodiment of the present invention, and the differences from the first embodiment will be described below.

That is, the relay coil 19 includes a relay switch 23 in addition to the relay switch 13, and this relay switch 23 has a movable contact piece c and fixed contact pieces a and b similar to the relay switch 13. And AC power supply 1
A series circuit of a movable contact piece c and a normally open side fixed contact piece a of a relay switch 23 and a fan heater 25 are connected between one end side 11a and the other end side 11b of the relay switch 23.

According to this third embodiment, when the power to the capacitor induction motor 14 is cut off by the relay switch 13, the fan heater 25 is also stopped, and the fan heater 25 related to ventilation is also operated. It turns out.

FIGS. 6 and 7 show a fourth embodiment in which the present invention is applied to a pipe fan, and the differences from the first embodiment will be described below.

That is, the capacitor induction motor 26 replaces the capacitor induction motor 14, and is composed of a main winding 27, an auxiliary winding 28, and a capacitor 29, and its electrical connection is made between the main winding 15, the auxiliary winding 28, and the capacitor 29 shown in FIG. This is similar to the winding 17 and capacitor 18.

Although not shown, this capacitor induction motor 26 is disposed inside a case, and a propeller fan 30, which is an axial fan, is connected to its rotating shaft.The case is connected to a pipe communicating with the outdoors. It's embedded.

In this case, the propeller fan 30 has an air volume-static pressure characteristic as shown in FIG. 7, and the air volume and static pressure are determined by the length of the pipe, that is, by the load amount. become. Therefore, Figure 7 shows the propeller fan 3
Point E, which shows the maximum air volume, is the intersection point D of the motor torque curve TM and fan torque curve TFB in FIG. 2, and point F, which shows the maximum static pressure, is the motor torque curve in FIG. 2. This is the intersection C between the curve TM and the fan torque curve TFA.

Therefore, in this fourth embodiment as well, the operating state of the relay switch 13 is released when the voltage between the terminals of the auxiliary winding 28 falls below the voltage Va, and as in the first embodiment, the operation state of the relay switch 13 is released. The effect of this can be obtained.

FIGS. 8 and 9 show a fifth embodiment in which the present invention is applied to a general kitchen ventilation fan, and the differences from the fourth embodiment will be described below.

That is, the capacitor induction motor 31 replaces the capacitor induction motor 26, and consists of a main winding 32, an auxiliary winding 33, and a capacitor 34, and its electrical connection is as shown in FIG. This is similar to the winding 28 and capacitor 29.

Although not shown, this capacitor induction motor 31 is disposed within an outer frame, and has a propeller fan 35, which is an axial fan, connected to its rotating shaft.
The outer frame faces outdoors and is fitted into a mounting hole in the room wall.

[0044] A filter for collecting oil dust contained in the exhaust gas is removably attached to the indoor opening of the outer frame.

FIG. 9 shows the motor torque curve TM of the capacitor induction motor 31, the fan torque curve TF of the propeller fan 35, and the voltage V between the terminals of the auxiliary winding 33. Therefore, the capacitor induction motor 31 rotates at a rotation speed Rd indicated by the intersection of the motor torque curve TM and the fan torque curve TF in a steady operating state, and the voltage across the terminals of the auxiliary winding 33 at that time is the voltage Vd. .

However, when the filter in the outer frame collects oil dust and becomes clogged, the number of revolutions of the propeller fan 35, that is, the number of revolutions of the capacitor induction motor 31, decreases. , the voltage between the terminals of the auxiliary winding 33 also decreases.

Thereafter, when the air volume becomes about 70% of that of steady operation, that is, when the rotation speed of the capacitor induction motor 31 becomes less than the limit rotation speed Rc, which is about 20% lower than the steady rotation speed Rd, the propeller fan The evacuation capacity through 35 is significantly reduced, indicating that it is time to replace the filter.

Therefore, when the voltage between the terminals of the auxiliary winding 33 falls below the voltage Vc corresponding to the rotational speed limit Rc,
The operating state of the relay switch 13 is released, and the notification lamp 16 is activated to notify that it is time to replace the filter. That is,
The applicable range of the propeller fan 35 is between the rotational speeds Rc and Rd.

By the way, in the first embodiment, the centrifugal multi-blade fan 21 having the air volume-static pressure characteristics as shown in FIG. 3 is used, but for example, in the sixth embodiment of the present invention shown in FIG. When using a centrifugal multi-blade fan that has air volume-static pressure characteristics that are marked as "limit", such as
The scope of application is up to the limit.

In each of the above embodiments, the auxiliary windings 17, 28
Alternatively, the relay coil 19 that detects the voltage between all 33 terminals is used, but these auxiliary windings 17,
An intermediate tap may be provided at 28 or 33 and a relay coil may be used to detect the voltage between some terminals.
Furthermore, a relay coil that detects the voltage between the terminals of the capacitors 18, 28, or 34 may be used.

[0051] In addition, the present invention is not limited to the above-mentioned embodiments, and it goes without saying that it can be implemented with appropriate modifications within the scope of the gist.

[0052]

[Effects of the Invention] As explained above, the abnormality detection device for a ventilation system of the present invention detects the voltage between the terminals of some or all of the auxiliary windings of the capacitor induction motor that drives the fan or the voltage between the terminals of the capacitor. When this value falls below the applicable range of the fan, the power supply to the capacitor induction motor is substantially cut off and the alarm is activated, so that the fan, that is, the capacitor induction motor, is prevented from overloading, locking accidents, etc. When an abnormality occurs, it can be quickly and reliably detected, the power can be cut off, and this can be notified, and it can be manufactured at a low cost.

[Brief explanation of drawings]

FIG. 1 is an electrical configuration diagram showing a first embodiment of the present invention.

[Figure 2] A diagram showing the relationship between the rotation speed and torque curve of a capacitor induction motor and the voltage between the terminals of the auxiliary winding.

[Figure 3] Fan air volume vs. static pressure characteristic diagram

[Fig. 4] A diagram corresponding to Fig. 1 showing a second embodiment of the present invention.

[Figure 5
]A diagram corresponding to FIG. 1 showing a third embodiment of the present invention

FIG. 6 is a diagram corresponding to FIG. 1 showing a fourth embodiment of the present invention.

[Figure 7] Diagram equivalent to Figure 3

FIG. 8 is a diagram corresponding to FIG. 1 showing a fifth embodiment of the present invention.

[Figure 9
】Equivalent figure to Figure 2

FIG. 10 is a diagram corresponding to FIG. 3 showing a sixth embodiment of the present invention.

[Fig. 11] A diagram corresponding to Fig. 1 showing a conventional example

[Explanation of symbols]

In the drawing, 13 is a relay switch (opening control means), 14
is a capacitor induction motor, 15 is a main winding, 16 is a notification lamp (notification means), 17 is an auxiliary winding, 18 is a capacitor, 19 is a relay coil (voltage detection means), 21 is a centrifugal multi-blade fan (fan), 26 is a capacitor induction motor, 2
7 is the main winding, 28 is the auxiliary winding, 29 is the capacitor, 30
is a propeller fan, 31 is a capacitor induction motor, 32 is a main winding, 33 is an auxiliary winding, 34 is a capacitor, and 35 is a propeller fan.

Claims (1)

[Claims] [Claim 1] A main winding for rotationally driving a fan;
In a ventilation system having a capacitor induction motor consisting of an auxiliary winding and a capacitor, a voltage detection means for detecting a voltage between terminals of a part or all of the auxiliary winding or a voltage between the terminals of a capacitor, and a detected voltage of the voltage detection means an abnormality detection device for a ventilation system, comprising circuit opening control means for substantially cutting off power to the electric motor and operating a notification means when the value falls below a value within the applicable range of the fan.