JP2945817B2 - DC fan motor with constant air volume control - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC fan motor having a constant air volume control for use in duct ventilation equipment such as a range hood or a ceiling-mounted type ventilation fan.

[0002]

2. Description of the Related Art In recent years, for a range hood, a ceiling-mounted type ventilating fan, etc., a fan motor having good controllability capable of ventilating at an optimum air flow according to a cooking state or a living room situation has been demanded.

Conventionally, this type of fan motor changes its air volume due to external factors such as the state of a duct, and requires the use of a dedicated sensor called a thermistor to detect the air volume. As the distance becomes longer, there is a problem that dust or the like adheres to the surface of the thermistor and the detection air volume changes. Therefore, we have already proposed a method as shown in FIGS.

As shown in FIG. 1, reference numeral 51 denotes a DC fan motor on which a DC motor 52 is mounted, and a discharge port 58 thereof is connected to a duct 59. The duct 59 guides indoor air contaminated by smoke and tobacco waste gas sucked by the DC fan motor 51 through the wall 60 of the building to the outside. The rotation of the DC motor 52 is controlled by an energization control unit 53 that controls energization to the stator windings according to the rotor position, and a rotation speed detection unit 54 detects the rotation speed of the DC motor 52 based on the control state. 57 is a DC fan motor 5 of strong, medium, weak, etc.
Air flow instructing means for instructing the operation air flow of 1;
A specified rotation speed calculating means for calculating a specified rotation speed at a voltage applied to the DC motor 52 for realizing each of the medium and weak operating air flow rates. Reference numeral 56 denotes a DC motor 52 detected by the rotation speed detecting means 54 by the applied voltage control means. Applied voltage V
A change applied voltage difference ΔV (n) is obtained from a difference ΔN (n) between the operating rotation speed in (n) and the specified rotation speed calculated by the specified rotation speed calculation means 61, and the voltage V (n + 1) to be applied next is obtained. ) Is determined, an applied voltage for sending a signal to the energization control means 53 is sent, and the applied voltage to the DC motor 52 is controlled.

In the above configuration, the power supply control means 53
The energization to the windings is switched according to the rotor position of the C motor 52, and the DC motor 52 rotates at a rotational speed according to the duct loss in the air path and L in the figure. At this time, the rotation speed detection means 54 detects the operating rotation speed Na from the switching speed of the current supply to the winding of the current supply control means 53. Next, assuming that the operating air volume instructed by the air volume instructing unit 57 is Qm in the figure, the specified rotation speed calculating unit 61 calculates the specified rotation speed Nma required to operate at the indicated airflow Qm at the current applied voltage Va. , The applied voltage control means 56 compares the operating speed Na with the specified speed Nma. As a result of the comparison, as shown in FIGS. 11 and 12, when Na <Nma, the centrifugal blower is used, and as can be seen from the drawing, it is operated at a flow rate larger than the indicated flow rate Qm. Then, the applied voltage control means 56 lowers the voltage by Δva in the figure and sets the applied voltage to Vb.
In this state, the rotational speed detecting means 54 again detects the operating rotational speed at the applied voltage Vb after the change, Nb in the figure, and the prescribed rotational speed calculating means 61 performs the prescribed rotational speed required for operating at the indicated airflow Qm at Vb. Nmb is calculated, and the applied voltage control means 56 compares the operating rotational speed Nb with the specified rotational speed Nmb. As a result of the comparison, as shown in the figure, when Nb> Nmb, the indicated airflow Q is opposite to the case where the operation is performed with the applied voltage Va.
m, the applied voltage needs to be increased. The applied voltage control means 56 reduces the voltage by Δvb in the figure to set the applied voltage to Vc, and the rotation speed detecting means 54 again Applied voltage V after change
c, the specified rotation speed calculating means 61 calculates the specified rotation speed Nmc required for operation at the indicated airflow Qm at Vc, and the applied voltage control means 56 calculates the operating rotation speed Nc. And the specified rotation speed Nmc. As a result of the comparison, when Nc <Nmc as shown in the figure, it is necessary to reduce the applied voltage because the operation is performed at a flow rate larger than the designated air flow rate Qm, as in the case of Va. And the applied voltage is set to VL. At this time, as shown in the figure, the rotational speed NL at the applied voltage VL is equal to the rotational speed Nm required to operate at the indicated airflow Qm at the applied voltage VL.
When it is equal to L, the DC fan motor 51 is operated at the instructed air volume Qm.
Is to maintain the applied voltage VL to secure the air volume Qm. The adjustment voltage for each applied voltage is Δva>Δvb> Δv
With c, the airflow was gradually approaching the indicated airflow.

FIG. 13 shows an example of a specific circuit of a main part. A rotation speed detecting means 54, an applied voltage control means 56, and a prescribed rotation speed calculating means 61 are constituted by a microcomputer 62, a switching power supply 63 and peripheral circuits. ing.
The energization control means 53 is composed of a switching element, and controls the current supply from the switching power supply 63 to the winding of the DC motor 52 by the gate signal of the microcomputer 62.

[0007]

SUMMARY OF THE INVENTION Such a conventional DC
The fan motor has a problem that the user does not notice that the pressure loss has increased compared with the initial construction due to external factors such as clogging of the filter and entry of foreign matter into the duct. Further, when the pressure loss is significantly increased, there is a problem that the equipment is damaged because the air flow is controlled to be constant beyond the capacity of the motor.

The present invention solves the above-mentioned problems, and eliminates the need for using a special sensor such as a pressure sensor to reduce the increase in pressure loss due to external factors such as clogging of a filter and entry of foreign matter into a duct. To inform the first
The purpose of.

A second object is to suppress control beyond the capability of the motor due to a significant increase in pressure loss.

[0010]

Means for Solving the Problems A constant air flow control D according to the present invention.
In order to achieve the first object, the C fan motor comprises a DC fan motor having a DC motor mounted thereon, and
Energization control means for controlling energization of the DC motor, rotation speed detection means for detecting the operation rotation speed of the DC motor from the operation of the energization control means, and air flow instructing means for instructing the operation air flow of the DC fan motor; And D for operating at the air volume instructed by the air volume instructing means.
A specified rotation number calculating means for calculating a specified rotation number at a voltage applied to the C motor; and an operating rotation number detected by the rotation number detecting means being equal to the specified rotation number obtained by the specified rotation number calculating means. Voltage control means for controlling the applied voltage of the DC motor so as to obtain; static pressure calculating means for calculating the static pressure applied to the DC fan motor from the operating speed detected by the speed detecting means; A maximum static pressure storing means for storing a maximum static pressure at the air volume instructed by the instructing means, and detecting a static pressure obtained by the static pressure calculating means which is equal to or higher than a predetermined static pressure stored in the maximum static pressure storing means In this case, a constant-flow-rate control DC fan motor including pressure loss increase notification means for notifying an increase in pressure loss is provided.

The second means is a DC fan motor having a DC motor mounted thereon, an energization control means for controlling energization of the DC motor, and an operation speed of the DC motor is detected from the operation of the energization control means. Rotation speed detection means, air flow amount instruction means for instructing the operation air flow amount of the DC fan motor, and a regulation for calculating a prescribed rotation number at a voltage applied to the DC motor for operating at the air flow amount designated by the air flow amount designation means Rotation speed calculating means, and an applied voltage for controlling the applied voltage of the DC motor so that the operating rotation speed detected by the rotation speed detecting means is equal to the specified rotation speed determined by the specified rotation speed calculation means. When the control means and the applied voltage control means attempt to control the applied voltage to the DC motor to a predetermined voltage I or more,
A DC fan motor having a constant air volume control provided with an overcapacity notifying means for notifying that the capacity of the C fan motor has been exceeded.

Further, in order to achieve the second object, the third
Means is provided with a constant air flow control DC fan motor provided with an emergency energization control means for stopping energization of the DC motor when the applied voltage control means attempts to control the applied voltage to the DC motor to a predetermined voltage I or more. I do.

The fourth means is that the applied voltage control means is D
When the voltage applied to the C motor is controlled to be equal to or higher than the predetermined voltage I, the air volume constant control is provided by providing maximum applied voltage control means for controlling the voltage applied to the DC motor to a predetermined voltage II lower than the predetermined voltage I. The configuration is a DC fan motor.

[0014]

According to the first aspect of the present invention, the static pressure applied to the DC fan motor is calculated by the static pressure calculating means from the operating rotational speed detected by the rotational speed detecting means. The calculated static pressure is compared with the maximum static pressure at each air volume indicated by the air volume instruction means stored in the maximum static pressure storage means, and the static pressure obtained by the operation is determined to be greater than the maximum static pressure stored in advance. Upon detection, an increase in pressure loss, such as clogging of the filter or entry of foreign matter into the duct, is detected, and the pressure loss increase notification means can issue an alarm to the user.

Further, according to the configuration of the second means, when the applied voltage control means attempts to control the applied voltage to the DC motor to a predetermined voltage I or more, it is determined that the over-capacity notifying means has exceeded the capacity of the DC fan motor. An alarm can be issued to the user.

Further, when the applied voltage control means attempts to control the applied voltage to the DC motor to a predetermined voltage I or more by the configuration of the third means, the emergency energization control means determines that the capability of the DC fan motor has been exceeded. The power supply to the DC fan motor can be stopped.

According to the fourth means, when the applied voltage control means attempts to control the applied voltage to the DC motor to a predetermined voltage I or more, the maximum applied voltage control means does not exceed the capability of the DC fan motor. Predetermined voltage lower than voltage I
II can be controlled.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. As shown, 1 is DC
A DC fan motor equipped with a motor 2 and a discharge port 8
Is connected to the duct 9, and the suction port 12 is provided with a filter 16. Duct 9 is DC fan motor 1
This is a duct that guides indoor air contaminated with smoke and waste gas generated by cooking through the wall 10 of the building to the outside of the building. The rotation of the DC motor 2 is controlled by energization control means 3 for controlling energization to the stator windings according to the position of the rotor, and the rotational speed detecting means 4 detects the rotational speed of the DC motor 2 according to the control state. 7
Is an air flow rate instructing means for instructing the operation air flow rate of the DC fan motor 1 such as strong, medium, and weak. The specified rotation speed calculating means for calculating
Is a voltage applied from the difference ΔN (n) between the operating speed at the applied voltage V (n) of the DC motor 2 detected by the speed detecting means 4 and the specified speed calculated by the specified speed calculating means 5. The difference ΔV (n) is determined, the voltage V (n + 1) to be applied next is determined, and an applied voltage control means for sending a signal to the energization control means 3. Maximum static pressure storage means 13 for storing the maximum static pressure. Reference numeral 13 denotes a static pressure calculating means which calculates the operating rotational speed N (rpm) detected by the rotational speed detecting means 4, the impeller diameter (mm), and the static pressure coefficient Kp. The static pressure Ps applied to the DC fan motor 1 is calculated by the following equation.

[0019]

(Equation 1)

Numeral 14 denotes a pressure loss increase notifying means, and a storage means for storing the static pressure obtained by the calculation of the static pressure calculating means 13 and the maximum static pressure.
5 is compared with the maximum static pressure stored in
Judgment control is performed to determine whether or not the pressure loss is abnormally increased as compared with the initial construction due to external factors such as clogging of 6 and entry of foreign matter into the duct. Other configurations are the same as those of the conventional example.

In the above configuration, when the power supply of the DC fan motor 1 is turned on, the operation is started in accordance with the procedure of the program shown in the flowchart of FIG. First, an initial voltage is output in step 18 and an initial gate signal is output in step 19 to rotate the DC motor 2. Next, at step 20, the rotor position of the DC motor 2 is detected, and a gate signal corresponding to the detected position is output at step 21. After the change time of the gate signal is measured in step 22, the operation speed is calculated from this change time in step 23 and held. Then, in step 24, the airflow instruction signal is taken in to confirm the indicated airflow, the static pressure applied to the DC fan motor is calculated in step 25, the maximum static pressure in the indicated airflow is searched in step 26, and the calculation is performed in step 27. The obtained static pressure is compared with the retrieved maximum static pressure. As a result of the comparison, if the calculated static pressure is large, it is determined in step 28 that the pressure loss is abnormally increased compared to the initial construction due to external factors such as clogging of the filter 16 and entry of foreign matter into the duct. And alert the user. Also,
If the calculated static pressure is small, the routine proceeds to step 29, where a specified rotation speed that matches the instructed air volume and the applied voltage is calculated, and compared with the operation rotation speed held in step 23 in step 30. As a result of the comparison, if the number of rotations is the same, the process returns to step 20, and thereafter the operation is continued by repeating this. As a result of the comparison, if the operating speed is different from the specified speed, the difference between the operating speed and the specified speed is calculated in step 31, the output voltage of the switching power supply 17 is determined and output in step 32, and the process returns to step 20. Thereafter, the operation is continued by this repetition.

FIG. 3 shows an example of a specific circuit of a main part.
Rotation speed detection means 4, applied voltage control means 6, specified rotation speed calculation means 5, static pressure calculation means 13, pressure loss increase notification means 1
4. The maximum static pressure storage means 15 is the microcomputer 11
And a switching power supply 17 and peripheral circuits. The energization control means 3 is constituted by a switching element, and controls the current supply from the switching power supply 17 to the winding of the DC motor 2 by the gate signal of the microcomputer 11.

As described above, according to the DC fan motor of the first embodiment of the present invention, the static pressure applied to the DC fan motor 1 is calculated from the operating speed detected by the speed detecting means 4. The static pressure calculating means 13 for obtaining the static pressure is provided, and the maximum static pressure storing means 15 for storing the maximum static pressure at each air volume indicated by the air volume indicating means 7 is provided. A pressure loss increase notification means for comparing the maximum static pressure stored in the pressure storage means 15 with a maximum static pressure obtained by calculation and for issuing an alarm to the user when the static pressure is detected to be higher than the maximum static pressure stored in advance. With the provision of 14, it is used that the pressure loss is abnormally increased compared to the initial construction due to external factors such as clogging of the filter 16 and entry of foreign matter into the duct 9. Caution for the user can be subjected to cause investigation and countermeasure of increasing the pressure loss for.

Next, a second embodiment of the present invention will be described with reference to FIGS. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description is omitted. As shown in FIG.
When the next applied voltage to the motor 2 is determined to be a value equal to or higher than the predetermined voltage I, it is an over-capacity notifying means for notifying that the capacity of the DC fan motor 1 has been exceeded.
The configuration is the same as that of the embodiment.

In the above configuration, when the power supply of the DC fan motor 1 is turned on, the operation is started according to the procedure of the program shown in the flowchart of FIG. Here step 24
The steps up to the step of taking in the air flow rate instruction signal and confirming the indicated air flow rate are the same as those in the first embodiment. A prescribed rotation speed matching the indicated air flow rate and the applied voltage is calculated in step 35 after step 24 and held in step 23. The operation speed is compared with that in step 36. As a result of the comparison, if the number of rotations is the same, the process returns to step 20, and thereafter the operation is continued by repeating this. Next, when the operation speed is different from the specified speed as a result of the comparison, the difference between the operation speed and the specified speed is calculated in step 37, the output voltage of the switching power supply 17 is determined and output in step 38, and in step 39, The applied voltage after the change and the predetermined voltage I which is the performance limit voltage of the DC fan motor 1
Compare with As a result of the comparison, if the applied voltage after the change is smaller than the predetermined voltage I, the process returns to the step 20, and thereafter the operation is continued by repeating this. Next, if the applied voltage after the change is equal to or higher than the predetermined voltage I, a warning is issued to the user in step 40 that the capacity of the DC fan motor 1 has been exceeded. Then, the process returns to step 20, and the operation is continued by this repetition.

As described above, according to the DC fan motor having the constant air volume control of the second embodiment of the present invention, the DC fan motor 1
Is provided, and the applied voltage control means 6 attempts to control the applied voltage to the DC motor 2 to be equal to or higher than the predetermined voltage I by providing the over-capacity notifying means 33 for judging that the user has exceeded the capacity. Then, when the capacity over notification means 33 exceeds the capacity of the DC fan motor 1, a warning can be issued to the user, so that the clogging of the filter 16 and the duct can be performed similarly to the first embodiment. In the case of an abnormal increase in the applied voltage exceeding the capability of the DC fan motor 2 due to an external factor such as the intrusion of a foreign substance into the inside of the DC fan 9, the cause can be investigated and countermeasures can be taken.

Next, a third embodiment of the present invention will be described with reference to FIGS. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description is omitted. As shown in FIG.
When the next applied voltage to the motor 2 is determined to be a value equal to or higher than the predetermined voltage I, it is an emergency energization control unit that sends a signal to the energization control unit 3 to stop and control the operation of the DC fan motor. The configuration is the same as that of the embodiment.

In the above configuration, when the power supply of the DC fan motor 1 is turned on, the operation is started in accordance with the procedure of the program shown in the flowchart of FIG. Where step 31
Up to the step of calculating the difference between the operating rotation speed and the specified rotation speed, the steps are the same as in the first embodiment.
In step 3, the next applied voltage is determined from the rotation speed difference, and step 44
Then, the next applied voltage is compared with a predetermined voltage I which is a performance limit voltage of the DC fan motor 1. As a result of the comparison, if the applied voltage after the change is smaller than the predetermined voltage I, the applied voltage determined in step 43 is output from the switching power supply 17 in step 45, and the process returns to step 20. Thereafter, the operation is continued by repeating this operation. Is done. Next, if the applied voltage after the change is equal to or higher than the predetermined voltage I, the output voltage of the switching power supply 17 is set to zero in step 46, and the operation of the DC fan motor 1 is stopped.

As described above, according to the DC fan motor of the third embodiment of the present invention, the DC fan motor 1
The emergency voltage control means 41 which sends a signal to the power control means 3 to stop the operation of the DC fan motor 1 by estimating that the voltage exceeds the capacity of the DC fan motor 1 is provided. The next applied voltage is a predetermined voltage I
When trying to control as described above, the operation of the DC fan motor 1 is stopped, so that abnormal use exceeding the capability of the DC fan motor 2 can be prevented.

Next, a fourth embodiment of the present invention will be described with reference to FIGS. The same parts as those in the first and third embodiments are denoted by the same reference numerals, and the detailed description is omitted. As shown in the figure, 47 indicates that when the applied voltage control means 6 determines the next applied voltage to the DC motor 2 to a value equal to or higher than the predetermined voltage I, the next applied voltage to the DC fan motor is set to a predetermined voltage II lower than the predetermined voltage I. Is the maximum applied voltage control means for sending a signal to the energization control means 3, and the other configuration is the same as that of the first embodiment.

In the above configuration, when the power supply of the DC fan motor 1 is turned on, the operation is started in accordance with the procedure of the program shown in the flowchart of FIG. Here, step 44
Is the same as that of the third embodiment up to the step of comparing the next applied voltage with the predetermined voltage I which is the performance limit voltage of the DC fan motor 1. As a result of the comparison in step 44, the applied voltage after the change is smaller than the predetermined voltage I If it is small, the applied voltage determined in step 43 is output from the switching power supply 17 in step 45, and the process returns to step 20, and the operation is continued by repeating this operation. Next, if the applied voltage after the change is equal to or higher than the predetermined voltage I, the output voltage of the switching power supply 17 is set to the predetermined voltage II lower than the predetermined voltage I in step 49, and the operation of the DC fan motor 1 is controlled.

As described above, according to the DC fan motor of the fourth embodiment of the present invention, the DC fan motor 1
The maximum applied voltage control means 47 is provided to apply a predetermined voltage II not exceeding the capacity of the DC fan motor 1 to the DC motor 2 by estimating that the applied voltage does not exceed the capacity of the DC fan motor 1. When the next application voltage to the DC fan 2 is controlled to be equal to or higher than the predetermined voltage I, the DC fan motor 1 is operated by applying the predetermined voltage II that does not exceed the capability of the DC fan motor 1 to the DC fan motor. It is possible to prevent the DC fan motor 1 from operating in a state exceeding the capacity of the DC fan motor 1.

[0033]

As is apparent from the above description of the embodiment, according to the present invention, the static pressure applied to the DC fan motor is calculated by the static pressure calculating means from the operating rotational speed detected by the rotational speed detecting means. The static pressure calculation means obtained by
A maximum static pressure storage means for storing a maximum static pressure at each air volume instructed by the air volume instructing means is provided, and a static pressure obtained by the static pressure calculating means and a maximum static pressure stored in the maximum static pressure storing means are stored. By using a special sensor such as a pressure sensor by providing a means for informing the user of an increase in pressure loss that compares and detects the calculated static pressure that is higher than the maximum static pressure stored in advance and issues an alarm to the user. To detect the abnormal increase in pressure loss compared to the initial construction due to external factors such as clogging of the filter and entry of foreign matter into the duct, and to alert the user. The user can investigate the cause of the increase in pressure loss and take countermeasures, and it is possible to prevent abnormal use of the equipment beforehand, so that a constant air flow system that can be used safely It is possible to provide a DC fan motor.

When the applied voltage control means attempts to control the applied voltage to the DC motor to a predetermined voltage I or more, D
Even if it is determined that the capacity of the C fan motor has been exceeded and a means for notifying the user of the ability to warn the user is provided, clogging of the filter and entry of foreign matter into the duct, etc.
The user can investigate the cause of the abnormal increase in the applied voltage exceeding the capability of the DC fan motor due to an external factor and take countermeasures, thereby preventing the abnormal use of the device. Therefore, it is possible to provide a constant-flow-rate control DC fan motor that can be used safely.

Further, when the applied voltage control means attempts to control the next applied voltage to the DC motor to a predetermined voltage I or more, it is estimated that the capacity exceeds the capability of the DC fan motor.
By providing the emergency energization control means for sending a signal to the energization control means to stop the operation of the C fan motor, the operation of the DC fan motor is stopped when it is estimated that the capacity of the DC fan motor will be exceeded. , Because the DC fan motor is not operated beyond its capacity, the safe airflow constant control D that does not cause equipment damage
A C fan motor can be provided.

Further, when the applied voltage control means attempts to control the next applied voltage to the DC motor to a predetermined voltage I or more, it is estimated that the applied voltage exceeds the capability of the DC fan motor.
Even if the maximum applied voltage control means for setting the predetermined voltage II that does not exceed the capacity of the C fan motor as the applied voltage to the DC motor is provided, if it is estimated that the capacity of the DC fan motor will be exceeded, the capacity of the DC fan motor is reduced. Since the DC fan motor is operated by applying a predetermined voltage II not exceeding the DC fan motor, it is possible to prevent the DC fan motor from being operated in a state exceeding the capability of the DC fan motor. It is possible to provide an air flow constant control DC fan motor having high operability.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a DC fan motor with constant air volume control according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing an example of a program for the operation.

FIG. 3 is a circuit diagram of the main part.

FIG. 4 is a configuration diagram of a DC fan motor with constant air volume control according to the second embodiment.

FIG. 5 is a flowchart showing an example of a program for the operation.

FIG. 6 is a configuration diagram of a DC fan motor with constant air volume control according to the third embodiment.

FIG. 7 is a flowchart showing an example of a program for the operation.

FIG. 8 is a configuration diagram of a DC fan motor with constant air volume control according to the fourth embodiment.

FIG. 9 is a flowchart illustrating an example of a program for the same operation.

FIG. 10 is a configuration diagram of a conventional fan motor.

FIG. 11 is a graph showing the relationship between the applied voltage and the number of rotations.

FIG. 12 is a static pressure-air flow graph showing the same operation characteristics.

FIG. 13 is a circuit diagram of the main part.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 DC fan motor 2 DC motor 3 energization control means 4 rotation number detection means 5 specified rotation number calculation means 6 applied voltage control means 7 air volume indication means 13 static pressure calculation means 14 pressure loss increase notification means 15 maximum static pressure storage means 33 capacity Over notification means 41 Emergency energization control means 47 Maximum applied voltage control means

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H02P 6/06

Claims (4)

(57) [Claims] 1. A DC fan motor having a DC motor mounted thereon, energization control means for controlling energization of the DC motor, and rotation speed detection means for detecting an operation speed of the DC motor from the operation of the energization control means. Air flow amount instructing means for instructing the operation air amount of the DC fan motor, and a specified rotation number calculating means for calculating a specified rotation number at a voltage applied to the DC motor for operating at the air amount instructed by the air amount instruction means. An applied voltage control means for controlling an applied voltage of the DC motor so that the operating speed detected by the speed detecting means is the same as the specified speed obtained by the specified speed calculating means; From the operating rotation speed detected by the rotation speed detecting means, the DC
Static pressure calculating means for calculating the static pressure applied to the fan motor;
A maximum static pressure storing means for storing a maximum static pressure at an air volume instructed by the air volume instructing means, and a static pressure obtained by the static pressure calculating means being equal to or higher than a predetermined static pressure stored in the maximum static pressure storing means A constant flow control DC fan motor provided with a pressure loss increase notification means for notifying an increase in pressure loss when a pressure loss is detected. 2. A DC fan motor equipped with a DC motor, energization control means for controlling energization of the DC motor, and rotation speed detection means for detecting an operation rotation speed of the DC motor from the operation of the energization control means. Air flow amount instructing means for instructing the operation air amount of the DC fan motor, and a specified rotation number calculating means for calculating a specified rotation number at a voltage applied to the DC motor for operating at the air amount instructed by the air amount instruction means. Applying voltage control means for controlling an applied voltage of the DC motor so that the operating speed detected by the speed detecting means is equal to the specified speed obtained by the specified speed calculating means; and When the applied voltage control means attempts to control the applied voltage to the DC motor to a predetermined voltage I or more, it is reported that the capability of the DC fan motor has been exceeded. Air volume constant control DC fan motor provided with the ability over informing means for. 3. An emergency energization control means for stopping energization of the DC motor when the applied voltage control means attempts to control an applied voltage to the DC motor to a predetermined voltage I or more. The air flow constant control DC fan motor described in the above. 4. When the applied voltage control means attempts to control the applied voltage to the DC motor to a predetermined voltage I or more,
3. The DC fan motor according to claim 1, further comprising maximum applied voltage control means for controlling a voltage applied to the motor to a predetermined voltage II lower than the predetermined voltage I.