JPH05292791A - Failure detector for fan - Google Patents

Abstract

PURPOSE:To centrally monitor failure of a plurality of cooling fans without fixing an individual sensor to the fan. CONSTITUTION:A current detector 7 is connected in series with a common line for connecting parallel connected cooling fans with a power supply in order to monitor total current flowing through the cooling fans 5. Allowable value of current fluctuation, occurring upon failure of single cooling fan 5, is preset in a comparator 8 connected with the current detector 7 and when a value detected through the current detector 7 exceeds the allowable value, an alarm 9 is sounded and a breaker is interrupted as required.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fan failure detection device for cooling electronic equipment.

[0002]

2. Description of the Related Art Electronic equipment, for example, semiconductor test equipment, is provided with a cooling fan for cooling a large number of electronic components mounted on a printed circuit board. Normally, the fan life is on the order of tens of thousands of hours (for example, nominally 50,000 hours), but if the fan fails, the electronic components generate heat and malfunction, and in the worst case, there is a risk of fire. Therefore, it is necessary to constantly monitor fan failures. There are AC fans and DC fans as types of fans, and failure modes include a disconnection mode in which current does not flow and a lock mode in which excessive current flows due to locking of the rotor or the like.

Generally, some fans are equipped with a sensor for detecting such a failure, and some are not. The AC fan accounts for a small proportion of the whole, but is usually not attached to it. On the other hand, many DC fans are attached, and there are two types of sensors, a magnetic force line type and a damper type. The magnetic force line type detects the magnitude of the magnetic flux generated by the DC motor, and the damper type detects the wind pressure with a microswitch. Both of these allow the detection signal to be taken out.

[0004]

However, the above-mentioned conventional device has the following drawbacks.

(1) If the fan does not have an abnormality detection sensor, the fan must be removed and replaced with a sensor-equipped fan, or the fan must be remodeled and individually mounted with a sensor. It was

(2) In a fan with a sensor, since the sensor and the sensor output are individually present, it is necessary to attach an alarm device or the like to each of them, and thus it is not possible to perform intensive monitoring. It was In particular, when there are a large number of fans to be monitored, such as when a plurality of electronic devices are arranged and operating simultaneously, individual monitoring is impractical.

(3) A fan without a sensor cannot be monitored, and therefore, measures have been taken to replace the fan early before the end of its service life, and effective use of resources has not been achieved.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned drawbacks of the prior art and provide a fan failure detection device capable of performing centralized monitoring without distinction between AC and DC.

[0009]

A cooling fan failure detection device of the present invention is a fan failure detection device for cooling an electronic device, wherein a current flowing through one or more fans is detected on a common line. A comparator that compares the value detected by the current detector with the allowable value of the current flowing through one or more fans during normal operation, and outputs an abnormal signal when the detected value exceeds the allowable value. And an alarm device that issues an alarm when an abnormal signal is output. The cooling fan includes both AC and DC.

[0010]

When a failure in the disconnection mode occurs in one unit, the current for one unit stops flowing, so the detected value detected by the current detector is below the lower limit of the allowable value. Therefore,
An abnormal signal is output from the comparator, the alarm device is activated, and the alarm sounds.

When a lock mode failure occurs in one unit,
Since the excess current flows, the detected value detected by the current detector exceeds the upper limit of the allowable value. Therefore,
A signal is output from the comparator, the alarm device is activated, and the alarm sounds.

Since a current is used as a parameter for failure detection instead of magnetic force lines or wind pressure, common detection can be performed regardless of AC or DC, and by detecting the current flowing through the common line, centralized monitoring is performed regardless of the presence or absence of a fan sensor. Is possible.

[0013]

EXAMPLES Examples of the present invention applied to an AC fan will be described below. FIG. 2 shows a main body that constitutes an electronic device such as a semiconductor test apparatus. A printed circuit board 2 on which a large number of electronic components are mounted is provided in multiple stages in the main body 1 (in the example shown in FIG.
And a fan chassis 3 for cooling a large number of electronic components mounted on the board 2 is detachably attached between the stages. Reference numeral 4 is a failure detection device described later. In the illustrated example, the fan chassis 3 are arranged in the upper, middle, and lower stages of the main body 1. As shown in FIG. 3, the fan chassis 3 can be replaced in units, and several, usually about three, cooling fans 5 are incorporated in the chassis.

As shown in FIG. 1, the three cooling fans 5 in each fan chassis 3 are connected in parallel, and further connected in parallel between the fan chassis 3 and the AC power source 6 through a common line.
It is connected to the. To one common line connected to the AC power source 6, a current detector 7 that intensively detects the current flowing through all (9) cooling fans 5 is connected in series. The current detector 7 can be composed of, for example, a digital voltmeter. The current detector 7 compares the detected value with this and the allowable value of the total current flowing through the six cooling fans 5 during normal operation, and outputs a fault signal when the detected value exceeds the allowable value. 8 is connected. When the number of fans is generalized to be n, if one out of n is damaged, Δ = ± (100 / n)% will change. Therefore,
The allowable value of the comparator 8 is set to be smaller than Δ. In the illustrated example, if one of the nine pieces is damaged, the change is ± 11%. Therefore, if the allowable value is set to ± 10%, the abnormality can be detected. The allowable value can be confirmed experimentally,
Theoretically, it can be set by adding the margin to the rated current of the fan. The comparator 8 is further connected to an alarm device 9 that issues an alarm when an abnormal signal is output from the comparator 8. Further, the output of the comparator 8 may be connected to a breaker for turning on / off the power supply of the semiconductor test apparatus, if necessary. The current detector 7, the comparator 8 and the alarm device 9 constitute the failure detection device 4 described above.

Next, the operation of the above configuration will be described. If a failure in the disconnection mode occurs in one cooling fan 5, the current for one cooling fan will not flow, so the detected value detected by the current detector 7 will be below the lower limit of the allowable value. Therefore, an abnormal signal is output from the comparator 8 and the alarm 9
Is activated and an alarm sounds. The probability is low, but 2
Even if more than one cooling fan fails in the disconnection mode at the same time, the same operation is performed and an alarm sounds.

When a lock mode failure occurs in one unit,
Since an excessive current flows, the detection value detected by the current detector 7 exceeds the upper limit of the allowable value. Therefore, an abnormal signal is output from the comparator 8 and the alarm device 9 is activated to sound an alarm. Similarly, when a plurality of lock mode failures occur, an alarm sounds similarly.

Even when failures in the disconnection mode and the lock mode occur at the same time, the excess current due to the failure in the normal lock mode is considered to be much larger than the current for one unit, which decreases due to the disconnection mode, and therefore is allowable. The upper limit of the value will be exceeded, and failure can be detected.

When a fan failure is detected in this way, the fan chassis 3 in which the failure has occurred is removed from the main body and replaced with a new fan chassis, or a damaged fan is found and replaced with a good product. At this time, the fan to be replaced may be an inexpensive fan without a sensor.

According to this embodiment, in particular, a fan such as an AC fan which does not have a sensor is incorporated to detect a failure of those fans in the already-shipped semiconductor measuring devices. In that case, there is no need for a major modification of replacing the fan with a fan with a sensor,
With a simple configuration in which a failure detection device including a digibol, a comparator, and an alarm device is simply connected to the common power line, fan failure detection can be performed, and the failure detection can be intensively performed. Therefore, it is not necessary to carelessly replace the fan before it reaches the end of its life, and it is possible to easily detect the fan that has reached the end of its life, effectively prevent heat generation and malfunction of electronic components, and prevent fire. The danger of is gone. In particular, in an electronic device such as a semiconductor test device in which a large number of devices are operated at the same time for a whole year without shutting down the power, it is difficult to detect occurrence of fan failure, which is very effective.

When the system has a number exceeding nine, it is properly divided and detected. In this case, as the failure detection device, the above-described number of divisions is prepared, but if a device for further supervising these is provided, centralized monitoring of any number can be performed. Also, when using a fan with a sensor, the sensor output attached to the fan is LE
By connecting to D or the like and lighting it when it fails, the failure detection device can know whether or not a fan failure has occurred as a whole, and the LED or the like can have a function of notifying which fan has failed. ..

[0021]

According to the present invention, the fan failure is detected by the current. Therefore, the fan failure can be concentratedly detected easily without distinction between AC and DC, and the reliability of the electronic equipment can be improved. it can.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a cooling fan failure detection device according to an embodiment of the present invention.

FIG. 2 is an internal configuration diagram of a main body according to the present embodiment.

FIG. 3 is a configuration diagram of a fan chassis according to the present embodiment.

[Explanation of symbols]

 1 Main Body 2 Printed Circuit Board 3 Fan Chassis 5 Cooling Fan 6 AC Power Supply 7 Current Detector 8 Comparator 9 Alarm

Claims (1)

[Claims] 1. A fan failure detection device for cooling an electronic device, comprising: a current detector for detecting a current flowing through one or more fans; and a detection value of the current detector and one or two during normal operation. Equipped with a comparator that compares the allowable value of the current flowing through more than one fan and outputs an abnormal signal when the detected value exceeds the allowable value, and an alarm device that issues an alarm when the abnormal signal is output. A fan failure detection device characterized by the above.