JPH07287625A - Device with cooling fan and fan controlling method - Google Patents

Abstract

PURPOSE:To continuously perform the cooling operation of a device by a fan without lowering the cooling effect as much as possible even when the rotation of the cooling fan is stopped due to a trouble. CONSTITUTION:In a device where plural cooling fans 3 and 4 are installed within the same duct and power supply is supplied from a power source unit 7 via each power feeding circuit for every fan, the power feeding circuit for every fan is provided with switches SW1 and SW2 opening and closing the each power feeding circuit. With the switches, rotation detection parts 8 and 9 and drive circuits 26 and 27 are provided as switch control means opening the switch of a pertinent fan power feeding circuit and stopping the power feeding to the fan whose rotation is stopped when the rotation of the fan is monitored for every fan and the fan rotation stoppage due to a fan abnormality is detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic computer equipped with a cooling fan, a peripheral device for the electronic computer, a device with a cooling fan used in other various electronic devices, and a fan control method therefor.

Particularly, in the present invention, in a device having a plurality of doubled cooling fans, even if some of the fans fail, the cooling fan is continuously operated without reducing the cooling efficiency as much as possible. It was made possible.

[0003]

2. Description of the Related Art FIG. 9 is an explanatory view of a conventional example.
Among them, 3 and 4 are fans (cooling fans), 5 and 6 are rotation sensors, 7 is a power supply unit, and 8 and 9 are rotation detectors.
Indicates an MPU (upper control unit).

In recent years, with the increase in reliability of electronic equipment and the like, in the electronic equipment and the like, a plurality of dual cooling fans are mounted in a duct to perform cooperative operation. An apparatus having two dual cooling fans will be described below.

The fans 3 and 4 shown in the figure are cooling fans mounted in a duct.
Includes a rotation sensor 5 for detecting the rotation of the fan,
6 is provided.

The fans 3 and 4 are motors (DC brushless motors) for rotating the blades of the fans.
Alternatively, an electronic circuit (transistor circuit or the like) for driving the motor is incorporated.

The rotation sensors 5 and 6 detect the rotation of a motor (fan motor) provided in the fan and output a fan rotation signal FANRTO. The fan rotation signal FANRTO outputs a pulse having a cycle corresponding to the rotation speed of the fan when the fan is rotating, and disappears when the fan stops due to a failure (low level L
become).

A power supply unit 7 is connected to the fans 3 and 4, and power is supplied to each fan via a power supply circuit for each fan. Further, the rotation sensor 5 is connected to a rotation detection unit 8 and the rotation sensor 6 is connected to a rotation detection unit 9 to detect the rotation of the fan.

The rotation detectors 8 and 9 detect the rotation state of the fan based on the fan rotation signal FANRTO from the rotation sensor, and when the fan stops rotating due to a failure or the like,
The fan alarm signal * FAL is output to the MPU 10. The MPU 10 detects a fan abnormality based on the fan alarm signal * FAL from the rotation detection units 8 and 9 and reports the abnormality to the host. .

In such an apparatus, if the fans 3 and 4 are rotating normally, the fan rotation signal FANRTO
Outputs a pulse of a constant cycle according to the rotation speed of the fan. At this time, the rotation detectors 8 and 9 determine that the fan rotation is normal, and set the fan alarm signal * FAL to a high level (normal state) and output it to the MPU 10.

After that, assume that one of the fans 3 and 4 fails. In this case, for example, when the fan 3 fails, the fan rotation signal FANRTO output from the rotation sensor 5 disappears (remains at a low level).
When the rotation detector 8 detects this state, it sets the fan alarm signal * FAL to low level and outputs it to the MPU 10.

When the fan alarm signal * FAL goes low, the MPU 10 recognizes that the fan 3 is in an abnormal state, and reports the fan abnormality to the host, for example.

[0013]

SUMMARY OF THE INVENTION The above-mentioned conventional device has the following problems. (1): The failure of the fan is not only the failure of the mechanical part of the fan but also the failure of the electronic circuit that drives the motor. When a failure occurs in an electronic circuit with a built-in fan, the fan locks at a certain rotational position, which interferes with the fan operation (cooling) during other normal operations.

In particular, when two fans are installed in series in the duct, if one fan is stopped and locked, the air flow from the other fans will be obstructed, and the normal fan load will increase. Will not be able to cool properly.

(2): If the fan stops operating due to a failure while the fan is still energized from the power supply unit, the invalid power consumption of the fan increases, resulting in abnormal heat generation or smoke generation. Sometimes.

(3): Among the fan failures, the motor stops due to external noise or temporary increase in frictional force of the mechanical part (for example, when dust or dust adheres to the bearing) (temporary failure). There is also a failure). Even if such a failure occurs, conventionally, only an alarm signal is output and the fan remains stopped.

Therefore, as in the case described above, the ineffective power consumption of the fan may increase, resulting in an abnormal heat generation state or a smoke generation state. The present invention solves such a conventional problem, and enables the cooling operation of the device by the fan to be continued without reducing the cooling effect as much as possible even when the cooling fan is stopped due to a failure or the like. The purpose is to

[0018]

FIG. 1 is a diagram for explaining the principle of the present invention. In FIG. 1, the same parts as those in FIG. 9 are designated by the same reference numerals. SW1 and SW2 are switches, 25 is a fan control circuit, and 26 and 27 are drive circuits.

In order to achieve the above-mentioned object, the present invention installs a plurality of cooling fans in duplicate in the same duct,
In a device with a cooling fan that supplies power to each of the fans 3 and 4 through a power supply circuit, a fan control circuit 25 that controls the fan is provided between the fans 3 and 4 and the power supply unit 7. It was

The fans 3, 4 are provided with rotation sensors 5, 6 for detecting the rotation of the fans, and a power supply unit 7 is connected via a fan control circuit 25. Power is supplied through a power supply circuit provided in the.

The fans 3 and 4 and the rotation sensors 5 and 6 are connected to a fan control circuit 25, and the fan control circuit 25 turns on / off the power supply circuits of the fans 3 and 4.
It controls off and so on.

The fan control circuit 25 includes switches SW1 and SW2 provided in the power supply circuit for each fan.
Drive circuits (DRV) 26 and 27 for driving the switches SW1 and SW2, and rotation detectors 8 and 9 are provided. Then, the rotation detectors 8 and 9 are connected to the MPU 10.

The rotation detector 8 is connected to the rotation sensor 5 of the fan 3, and the rotation detector 9 is connected to the rotation sensor 6 provided on the fan 4. Then, each of the rotation detectors monitors the rotation of the fan based on the fan rotation signal FANRTO output from each of the rotation sensors.

The switch SW1 is a switch provided in a power supply circuit to the fan 3, and the switch SW2 is a switch provided in a power supply circuit to the fan 4. These switches are signals TR-O output from the rotation detectors 8 and 9.
It is driven by drive circuits 26 and 27 based on N to turn on / off the power supply circuit provided for each fan.

[0025]

The operation of the present invention based on the above construction will be described with reference to FIG. (1): When the rotation of the fan is normal, the rotation detectors 8 and 9
The signal TR-ON output from is set to high level H, and the drive circuits 26 and 27 switch the switches SW based on this signal.
1, SW2 is driven on.

When the fan is in a rotation stopped state due to a failure or the like, this state is detected by the rotation detection units 8 and 9, and the signal TR-ON output from the rotation detection units 8 and 9 is set to the low level L. To do.

By this signal, the drive circuits 26, 27
Then, of the switches SW1 and SW2, the corresponding switch (switch of the power supply circuit to the fan whose rotation has stopped) is driven to OFF. Then, the power supply to the fan whose rotation has stopped is stopped.

As described above, when the rotation detectors 8 and 9 detect that the fan rotation has stopped due to a failure or the like,
Control is performed to stop the power supply to the fan whose rotation has stopped. At this time, the rotation detection unit outputs the fan alarm signal * F
Set AL to low level L (alarm state) and set MPU1
Report alarm to 0.

For example, assume that one of the fans 3, 4 fails. In this case, if the fan 3 fails,
Fan rotation signal FANR output from the rotation sensor 5
TO is gone.

The rotation detector 8 indicates the rotation stop state of this fan.
When the rotation detection unit 8 detects the signal, the signal TR-ON is set to the low level L, the drive circuit 26 turns off the switch SW1, and the power supply circuit to the fan 3 is cut off. Therefore, the power supply to the fan 3 is stopped, and the fan 3 stops rotating.

As described above, when the rotation of the fan is stopped due to the failure or abnormality of the fan, the power supply to the fan whose rotation is stopped is stopped. Therefore, the locked state of the fan is released, and the fan is allowed to rotate freely.

Therefore, for example, if two fans are installed in series and one of them fails, the failed fan will rotate freely, and the other normal fan will improve the cooling efficiency. The cooling operation can be continuously performed without dropping.

Further, since no current flows through the failed fan, the motor current does not increase, and heat generation and smoke generation can be prevented. (2): Also, as described above, when the rotation of the fan is stopped and the switch of the power feeding circuit is turned off, the MPU1
Based on the control signal from 0, the rotation detector outputs a signal to turn on the switch, and the drive circuit turns on the switch to try to restart the fan.

In this case, in the drive circuit, the switch provided in the power supply circuit of the fan whose rotation is stopped is turned on to supply power to the fan. That is, the fan whose rotation is stopped due to a failure of the fan or the like and whose power supply is stopped is supplied with power again to try restarting. This operation is performed for a predetermined time, and after the predetermined time has passed again, the power supply circuit of the fan is cut off.

When the fan failure is recovered by repeating this restart operation, the normal operation is performed as it is. In this way, the torque of the motor can be changed by restarting the fan, and a temporary fan failure (for example, when dust or dust adheres to the bearing) can be recovered.

[0036]

Embodiments of the present invention will be described below with reference to the drawings. 2 to 8 are views showing an embodiment of the present invention. In FIGS. 2 to 8, the same parts as those in FIGS. 1 and 9 are designated by the same reference numerals.

Reference numeral 12 is a load circuit, 13 is a magnetic disk module, 14 is a duct (case), 15 is a front end portion, 16 is a rear end portion, 17, 18 and 19 are printed boards, 2
0 and 21 are magnetic disk drive units, 22 is a mother board, 30 and 31 are transistors, 34 is a NOT circuit, 35 is a mono-multi circuit (MM: monostable multi-vibrator), 37 is an OR circuit, R1 and R2 are resistors, and C1 is Indicates a capacitor.

The signals of the respective parts are as follows. FA
NRTO: Fan rotation signal, TR-ON: Transistor on signal, ON-TRG: On trigger signal, * FA
L: Fan alarm signal (* indicates alarm at low level L).

§1: Description of fan mounting mode--see FIG. 2 FIG. 2 is an explanatory view of a fan mounting mode, FIG. A showing Example 1 and FIG. B showing Example 2. The fan mounting form of the device with a cooling fan includes the following forms.

In the example 1 shown in FIG. A, the load circuit 12 and the power supply unit 7 are mounted in the duct 14, and the two redundant fans 3 and 4 are connected in series with the power supply unit 7 interposed therebetween. This is an example of mounting (installed in series from the intake side to the exhaust side).

In this case, with respect to the power supply unit 7, the fan 3 is mounted on the intake side and the fan 4 is mounted on the exhaust side. Therefore, the cooling air sucked from the intake side of the duct 14 by the fans 3 and 4 is the load circuit 12 → the fan 3
→ Power supply unit 7 → Fan 4 flows in this order, and is exhausted from the fan 4 to the outside.

In this case, for example, when the fan 3 is stopped due to a failure and the blades of the fan are locked, it becomes difficult for the cooling air to flow in the part of the fan 3 and even if the fan 4 is operating normally, The cooling air exhausted from 4 is
It becomes less and the cooling efficiency becomes very poor.

Also, when the fan 4 is stopped due to a failure, the same state as described above is obtained. In addition, the solving means and the like in the case of the above state will be described later. In Example 2 shown in FIG. B, the load circuit 12 is provided in the duct 14 (the power supply unit is not shown), and the plurality of fans 3-1 to 3-1 are duplicated with the load circuit 12 interposed therebetween. -3 and 4-1 to 4-3 are mounted.

In this case, three fans 3-1, 3-2, 3-3 are mounted side by side on the intake side of the load circuit 12, and three fans 4-1 and 4 are installed on the exhaust side. -2, 4-3
Are installed side by side.

Therefore, the cooling air sucked from the intake side of the duct 14 by the fan is the fans 3-1 to 3-3.
→ Load circuit → Flows in the direction of fans 4-1 to 4-3 and is exhausted to the outside from fans 4-1 to 4-3.

§2: Description of Specific Example of Device with Cooling Fan--See FIG. 3 FIG. 3 is a device configuration diagram of an embodiment. An example of a magnetic disk module is shown in FIG. 3 as a specific example of a device with a cooling fan having the fan mounting mode shown in FIG. 2A.

As shown, the magnetic disk module 1
3 is provided with a duct (case) 14 having a front end portion 15 and a rear end portion 16, and in the duct 14, a printed board on which two magnetic disk drive units 20, 21, a control circuit, etc. are mounted. 17, 18, 19, a power supply unit 7, fans 3, 4, and a mother board 22 on which a control circuit and the like are mounted are provided.

In this case, the fans 3 and 4 are the power supply unit 7
Are installed in series with the two fans interposed therebetween, and the inside of the magnetic disk module 13 is cooled by these two fans.

The front end portion 15 side of the duct 14 is opened, and this opening is the cooling air suction side. Further, a part of the duct 14 on the rear end 16 side is opened, and this opening is on the exhaust side of the cooling air.

Therefore, the duct 1 is formed by the fans 3 and 4.
The cooling air sucked from the intake side of No. 4 has two magnetic disk drive units 20, 21, printed boards 17, 1,
8, 19, the mother board 22 → fan 3 → power supply unit 7 → fan 4 in that order, and is exhausted from the fan 4 to the outside.

§3: Description of control system configuration--see FIG. 4 FIG. 4 is a block diagram of the control system of the embodiment. Hereinafter, the configuration of the control system of the above-described device (device with a cooling fan) will be described.

The fans 3 and 4 shown in FIG.
4, which are cooling fans mounted in each of them, and each of these fans 3, 4 is provided with rotation sensors 5, 6 for detecting the rotation of the fan.

Further, the fans 3 and 4 are motors (DC brushless motors) for rotating the blades of the fans.
Alternatively, an electronic circuit (transistor circuit or the like) for driving the motor is incorporated.

The rotation sensors 5 and 6 detect the rotation of the motor provided in the fan and output the fan rotation signal FANRTO.
Is output. This fan rotation signal FANRT
When the fan is rotating, O outputs a pulse having a cycle corresponding to the rotation speed of the fan, and when the fan stops due to a failure,
The pulse disappears.

A fan control circuit 2 is provided for the fans 3 and 4.
A power supply unit 7 is connected via 5 and supplies power via a power supply circuit provided for each fan. In addition, the fans 3, 4 and the rotation sensors 5, 6
Is connected to the fan control circuit 25, and the fan control circuit 25 controls ON / OFF of the power sources of the fans 3 and 4. Specifically, it is as follows.

The fan control circuit 25 includes transistors 30 and 31 provided in the power supply circuit for each fan, and a drive circuit (DRV) 2 for driving each transistor.
6, 27 and rotation detection units 8 and 9 are provided. Then, the rotation detection units 8 and 9 are connected to the MPU 10 which is a higher-order control unit.

The rotation detecting section 8 is connected to the rotation sensor 5 of the fan 3, and the rotation detecting section 9 is connected to the rotation sensor 6 provided on the fan 4. Then, each of the rotation detectors monitors the rotation of the fan based on the fan rotation signal FANRTO output from each of the rotation sensors.

The transistor 30 is a transistor provided in a power supply circuit for the fan 3, and is a transistor 31.
Is a transistor provided in a power supply circuit for the fan 4.
These transistors are driven by drive circuits 26 and 27, respectively, based on the transistor ON signal TR-ON output from the rotation detection units 8 and 9, and turn on / off the power supply circuit provided for each fan. is there.

For example, when the transistor 30 is turned on, power supply from the power supply unit 7 to the fan 3 is started and the fan 3 rotates. However, when the transistor 30 is turned off, the power supply circuit to the fan 3 is cut off. , Power supply is stopped.

When the transistor 31 is turned on,
When power supply from the power supply unit 7 to the fan 4 is started and the fan 4 rotates, when the transistor 31 is turned off,
The power supply circuit to the fan 4 is cut off and the power supply is stopped.

§4: Description of the operation of the fan control circuit ...
Referring to FIG. 4, the operation of the fan control circuit will be described below with reference to FIG. When the rotation detection units 8 and 9 detect that the rotation of the fan has stopped due to a failure or the like, the rotation detection units 8 and 9 perform control to stop power supply to the fan whose rotation has stopped. At this time, the rotation detection unit sets the fan alarm signal * FAL to the low level L (alarm state) and outputs (reports) it to the MPU 10.

That is, if the fans 3 and 4 are rotating normally, the fan rotation signal FANRTO outputs a pulse of a constant cycle according to the number of rotations of the fan. Fan rotation signal FANRTO
Therefore, the rotation detector detects the rotation stop of the fan by monitoring this signal.

When the rotation of the fan is normal, the transistor ON signal TR-ON output from the rotation detectors 8 and 9 is output.
To the high level H, and based on this signal, drive circuit 2
6, 27 drive transistors 30, 31 on.

When the rotation of the fan is stopped due to a failure or the like, the rotation detectors 8 and 9 detect this state, and the transistor ON signal T output from the rotation detectors 8 and 9 is detected.
Set R-ON to low level L.

By this signal, the drive circuits 26, 27
Then, of the transistors 30 and 31, the corresponding one (the transistor of the power supply circuit to the fan whose rotation has stopped) is driven off. Then, the power supply to the fan whose rotation has stopped is stopped.

If the fan is normal, the rotation detectors 8 and 9 set the fan alarm signal * FAL to the high level H.
(Normal), and when the fan stops rotating due to a failure, the fan alarm signal * FAL is set to low level L.
It outputs (reports) to the MPU 10 as (alarm).

Now, it is assumed that one of the fans 3 and 4 has failed. In this case, for example, when the fan 3 fails, the fan rotation signal FA output from the rotation sensor 5
NRTO is gone.

The rotation detector 8 indicates the rotation stop state of this fan.
Then, in the rotation detection unit 8, the transistor ON signal TR-ON is set to low level L, the drive circuit 26 turns off the transistor 30, and the power supply circuit to the fan 3 is cut off. Therefore, the power supply to the fan 3 is stopped, and the fan 3 stops rotating.

§5: Description of Rotation Detecting Unit--See FIG. 5 FIG. 5 is a block diagram of the rotation detecting unit. The rotation detector 8 or 9 shown in FIG. 4 is configured as shown in FIG. 5, for example.

That is, the rotation detector has a resistor R
1, R2, capacitor C1, NOT circuit 34, mono-multi circuit (MM: monostable multi-vibrator) 35, MP
A U (microprocessor) 10 and an OR circuit 37 are provided.

The resistors R1 and R2 and the capacitor C1
The above circuit constitutes an input circuit and suppresses a noise component of the input signal. The NOT circuit 34 is of the Schmitt trigger type and has a hysteresis characteristic in the threshold voltage, and inputs a signal of a slow change by the capacitor C1 and converts it into a stable inverted signal. Even if the signal output from the rotation detector includes noise in the R1, R2, C1, and NOT34 circuits, a stable inverted signal can be obtained.

The mono-multi circuit (MM) 35 is triggered by the pulse signal output from the NOT circuit 34 and outputs a pulse having a constant width. The OR circuit 37 performs a logical sum operation of the output signal from the mono-multi circuit 35 and the output signal of the MPU 10 to obtain the transistor ON signal TR.
-ON is output.

The MPU 10 includes the transistors 30, 3
The on-trigger signal ON-TRG for driving No. 1 is generated and various controls are performed. The operation of the rotation detector is as follows.

A fan rotation signal FANRTO output from a rotation sensor of the fan is input to the rotation detector, and noise is suppressed in this signal by a circuit composed of resistors R1, R2 and a capacitor C1, but it is slowed down. It is a signal with a change.

The signal having this slow change is NO
The T circuit 34 converts the noise into a stable inverted pulse, and triggers the mono-multi circuit 35. When triggered by the pulse from the NOT circuit 34, the mono-multi circuit 35 outputs a pulse having a constant width determined by an internal time constant (having a time constant determined by a capacitor and a resistor).

The pulse output from the mono-multi circuit 35 is output to the OR circuit 37 and the MPU 10. In this case, the signal output from the mono-multi circuit 35 to the MPU 10 is the fan alarm signal * FAL, and the signal output from the mono-multi circuit 35 to the OR circuit 37 is the transistor-on signal TR-ON.

Further, in the MPU 10, when the fan is stopped due to a failure or the like based on the fan alarm signal * FAL, the on-trigger signal ON-TRG is output to the OR circuit 37. This on-trigger signal ON-
TRG is provided from the OR circuit 37 to the drive circuits 26, 2
7 is output as a transistor ON signal TR-ON.

§6: Description of operation example 1 based on time chart 1--see FIG. 6 FIG. 6 is a time chart of the rotation detector. Below, FIG.
The operation example 1 of the embodiment will be described based on FIG. This example
This is an example of stopping the power supply to the fan that has stopped rotating, when the fan that is operating normally stops rotating due to a failure or an abnormality.

In FIG. 6, is a fan rotation signal (FA
NRTO), is an output signal of the NOT circuit 34, is a fan alarm signal (* FAL), is an OR from the MPU 10.
On-trigger signal (ON-TR output to the circuit 37
G) indicates a transistor-on signal (TR-ON) output from the rotation detector to the drive circuit, and indicates a motor current Im flowing through the transistor.

When the fans 3 and 4 are operating normally, the fan rotation signal FANRTO is a pulse of a constant cycle, and this signal is inverted by the NOT circuit 34 and output to the mono-multi circuit (MM) 35.

In this case, the mono-multi circuit 35 outputs a pulse having a pulse width determined by the internal time constant.
Since the frequency of the output signal of the NOT circuit 34 is higher than this time constant, the output of the mono-multi circuit 35 remains at the high level if the fan is operating normally.

The on-trigger signal ON-TRG output from the MPU 10 remains at the low level L,
Since the output of the mono-multi circuit 35 is high level H, OR
Transistor on signal TR-ON which is 7 outputs of circuit 3
Is at a high level.

Therefore, in the drive circuits 26 and 27, the transistors 30 and 31 are driven to be turned on by the transistor ON signal TR-ON of the high level H. It is assumed that the fan operating normally in the above state fails (abnormality occurs) at the timing t1 and stops rotating. At this time, due to the failure of the fan, the fan gradually reduces its rotation speed and eventually stops rotating. When the rotation of the fan is completely stopped, the fan rotation signal FANR
TO disappears (state of low level L).

Therefore, the output of the NOT circuit 34 becomes the high level H. Then, when a predetermined time elapses from the timing t1, the signal output from the mono-multi circuit 35 becomes a low level L signal, and the fan alarm signal * F
AL also becomes low level L.

At this time, the on-trigger signal ON-TRG output from the MPU 10 remains at the low level L, so the transistor on-signal TR-ON output from the OR circuit 37 becomes the low level L.

As a result, among the drive circuits 26 and 27,
In the drive circuit in which the transistor ON signal TR-ON has become the low level L, the transistor is driven to be turned off to stop the power supply to the fan whose rotation has stopped (motor current Im = 0).

In this way, when power supply to the fan whose rotation has stopped is stopped, the locked state of the fan is released and the fan is allowed to rotate freely. §7: Description of operation example 2 according to time chart 1--see FIG. 7 FIG. 7 is a time chart of the rotation detection unit. Below, FIG.
An operation example 2 of the embodiment will be described based on FIG.

In this example, when the fan stops, the power supply circuit to the fan is turned on (transistor is turned on) assuming that the motor is stopped by a temporary disturbance element.
This is an example of restarting the fan.

In FIG. 7, is a fan rotation signal (FA
NRTO), is an output signal of the NOT circuit 34, is a fan alarm signal (* FAL), is an OR from the MPU 10.
On-trigger signal (ON-TR output to the circuit 37
G) indicates a transistor-on signal (TR-ON) output from the rotation detector to the drive circuit, and indicates a motor current Im flowing through the transistor.

When rotation of the fan is stopped due to failure or abnormality of the fan alarm, the fan rotation signal FANRTO becomes low level L, and the output of the NOT circuit 34 becomes high level H.

At this time, the fan alarm signal * FAL output from the mono-multi circuit 35 becomes low level L,
Transistor ON signal TR output from OR circuit 37
-ON also becomes a low level L, and the motor current Im disappears.

In such a fan rotation stop state, when the MPU 10 sets the on-trigger signal ON-TRG to the high level H at the timing t1, the transistor ON signal TR-ON output from the OR circuit 37 becomes the high level H. Become.

As a result, in the drive circuit, the transistor of the fan power supply circuit whose rotation is stopped is turned on to allow the motor current Im to flow. That is, the rotation of the fan is stopped due to a failure of the fan, etc.
Supply power and try restarting. This operation is performed for a predetermined time, and the power supply circuit of the fan is cut off again at timing t2.

In this case, at the timing t2,
Since the fan alarm signal * FAL is at the low level L and the fan is in the alarm state (a condition in which the failure of the fan is not recovered by the above-mentioned retry), the MPU 10 once sets the on-trigger signal ON-TRG to the low level L to turn on the transistor on signal. TR-ON is set to low level L, and the transistor turned on in the retry is turned off.

Next, at a timing t3 after a lapse of a predetermined time from the timing t2, the MPU 10 sets the on-trigger signal ON-TRG to the high level H again and the transistor-on signal TR-ON to the high level H to turn on the transistor. turn on.

As a result, the electric power is supplied to the motor to restart the motor for the second time. In this case, since the motor has started re-rotation at the next timing t4, the fan rotation signal FANRTO becomes high level H and the fan alarm signal * FAL also becomes high level H.

The MPU 10 judging this state judges that the motor has started re-rotation, and releases the on-trigger signal ON-TRG at the timing t6. After that, the fan rotates normally.

By performing the above processing, the following is possible. That is, among fan failures, there is a failure (temporary failure) in which the motor stops due to external noise, temporary increase in frictional force of the mechanical portion (for example, when dust or dust adheres to the bearing), or the like.

Even if such a failure occurs, the fan for which the power supply has been stopped is supplied again and an attempt is made to restart the fan. By repeating this restarting operation, if the failure of the fan is recovered, the normal operation is performed as it is.

In this way, by changing the torque of the motor by restarting the fan, the temporary failure of the fan as described above can be recovered. §8: MPU process description ... See FIG. 8 FIG. 8 is a process flowchart of the MPU. This process is a process performed by the MPU 10 in the operation example 2 shown in FIG. Hereinafter, the processing of the MPU will be described with reference to FIG. Note that S1 to S9 indicate processing steps.

The MPU 10 has a fan alarm signal * FA
When L is monitored (S1) and the fan alarm signal * FAL is at high level H (* FAL = H), another job is performed for a certain period of time (S2). That is, other jobs are performed while monitoring whether or not the fan alarm signal * FAL is at the high level H at regular time intervals.

When the fan alarm signal * FAL becomes low level L (alarm state), the MPU 10
Set the on-trigger signal ON-TRG to high level H (S
3), N is incremented (N = N + 1) (S4),
It is determined whether N = T (T: arbitrary integer) (S5).

As a result, if N = T is not satisfied, the process is repeated from S3, and if N = T, the MPU 10
Determines whether the fan alarm signal * FAL is at high level H (S6).

In this case, in the MPU 10, the on-trigger signal ON-TRG is set to the high level H for a fixed time (time until N = T), and after the elapse of the fixed time, the on-trigger signal ON-TRG is set to the low level L. Then, it is determined whether or not the fan alarm signal * FAL becomes the high level H.

As a result, if the fan alarm signal * FAL is at the high level H, it is determined that the fan has returned to the normal state, and the MPU 10 sets the on-trigger signal ON-TRG to the low level L (S9), and the processing of S1 is performed. Repeat from.

However, when the fan alarm signal * FAL is not at the high level H in the processing of S6, the MPU
10 is a low level L on-trigger signal ON-TRG
Set to (S7), and perform another job for a certain time (S7)
8) Then, the process is repeated from S3.

[0107]

As described above, the present invention has the following effects. (1): The failure of the fan is not only the failure of the mechanical part of the fan but also the failure of the electronic circuit that drives the motor. When a failure occurs in an electronic circuit with a built-in fan, the fan locks at a certain rotational position, which hinders another fan operation (cooling) during normal operation.

Particularly, when two fans are installed in series in the duct, if one fan is stopped and locked, the air flow from the other fans is obstructed, and the load on the normal fan increases. Will not be able to cool properly.

However, in the present invention, when the rotation of the fan is stopped due to the failure or abnormality of the fan, the power supply to the fan whose rotation is stopped is stopped. Therefore, the locked state of the fan is released, and the fan is allowed to rotate freely.

Therefore, for example, if two fans are installed in series and one of them fails, the failed fan will rotate freely, and the other normal fan will improve the cooling efficiency. The cooling operation can be continuously performed without dropping.

(2): If the fan stops operating due to a failure while the fan is still energized from the power supply unit, the invalid power consumption of the fan increases, resulting in abnormal heat generation or smoke generation. Sometimes.

However, in the present invention, when the rotation of the fan is stopped due to the failure or abnormality of the fan, the power supply to the fan whose rotation is stopped is stopped. Therefore, since no current flows through the failed fan, the motor current does not increase, and heat generation and smoke generation can be prevented.

(3): Among the fan failures, the motor stops due to external noise or temporary frictional force increase of the mechanical part (for example, when dust or dust adheres to the bearing) (temporary failure). There is also a failure).

Even when such a failure occurs, the present invention attempts to restart the fan by supplying the power again to the fan whose rotation is stopped due to the failure of the fan and the power supply is stopped.

If the fan failure is recovered by repeating this restart operation, the normal operation is performed as it is. In this way, by changing the torque of the motor by restarting the fan, it is possible to recover the temporary fan failure as described above.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is an explanatory diagram of a fan mounting mode according to an embodiment.

FIG. 3 is a device configuration diagram of an embodiment.

FIG. 4 is a block diagram of a control system of the embodiment.

FIG. 5 is a block diagram of a rotation detection unit in the embodiment.

FIG. 6 is a time chart 1 of the rotation detector in the embodiment.
Is.

FIG. 7 is a time chart 2 of the rotation detector in the embodiment.
Is.

FIG. 8 is a processing flowchart of an MPU in the embodiment.

FIG. 9 is an explanatory diagram of a conventional example.

[Explanation of symbols]

 3, 4 fan (cooling fan) 5, 6 rotation sensor 7 power supply unit 8, 9 rotation detection unit 10 MPU 26, 27 drive circuit (DRV) SW1, SW2 switch

Claims (6)

[Claims] 1. A device with a cooling fan, wherein a plurality of cooling fans are installed in the same duct, and power is supplied to each of the fans via respective power supply circuits. , A switch (SW1, SW2) for opening and closing each power supply circuit is provided, and the rotation of the fan is monitored for each fan, and when a fan rotation stop due to a fan abnormality is detected, the switch of the corresponding fan power supply circuit is opened. A device with a cooling fan is provided with switch control means for stopping power supply to the fan whose rotation has stopped. 2. A cooling fan-equipped device in which a plurality of cooling fans are installed in series in the same duct, and power is supplied to each fan through a power supply circuit of each fan. Each power supply circuit is provided with a switch (SW1, SW2) that opens and closes each power supply circuit, and when the fan rotation is monitored for each fan and a fan rotation stop due to a fan abnormality is detected, the corresponding fan power supply circuit An apparatus with a cooling fan, characterized in that switch control means for opening the switch to stop the power supply to the fan whose rotation has stopped is provided. 3. When the switch control means detects a fan rotation stop due to a fan abnormality and opens a switch of a corresponding fan power supply circuit to stop power supply to a fan whose rotation has stopped, the switch control means again switches the switch. 3. A fan restart control means for attempting restart of the fan by restarting the power supply to the fan whose rotation is stopped by opening the switch from the open position to the closed position. Equipment with cooling fan. 4. A device with a cooling fan, wherein a plurality of cooling fans are installed in the same duct, and power is supplied to each of the fans via respective power supply circuits. When a fan rotation stop due to a fan abnormality is detected, the power supply circuit to the fan whose rotation has stopped is cut off to stop the power supply to the fan. Method. 5. A device with a cooling fan, wherein a plurality of cooling fans are installed in series in the same duct, and power is supplied to each of the fans installed in series through respective power supply circuits. Cooling characterized by monitoring the fan rotation for each fan and shutting down the power supply circuit to the fan that stopped rotation when detecting the stop of fan rotation due to a fan abnormality. Control method for a device with a fan. 6. The fan rotation stop due to the fan abnormality is detected, the power supply to the fan that has stopped rotating is stopped, and then the power supply to the fan that has stopped rotating is restarted to restart the fan. A fan control method for a device with a cooling fan according to claim 4 or 5, characterized in that an attempt is made.