JPH09308091A - Device for determining failure of load - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine the failure of each load precisely even if there are a plurality of the same loads and dynamic loads are mixedly included with static loads. SOLUTION: A CPU 24 turns on transistors 131 to 134 and switching circuits 21, 23 to drive static loads such as a fan motor 12, an optical system 18 and a solenoid 16 and dynamic loads such as a main electric motor 15, a heater 20 and a high-tension power supply unit 22, and also to selectively detect the value of current flowing in each load. In the static loads, the detected value of current is compared with the values of upper and lower limits of a preset permissible current. A failure is determined when the detected value of current is more than the value of upper limit or less than the value of lower limit. In the dynamic loads, maximum and minimum values of currents are detected by changing load conditions into both states in which maximum and minimum currents are caused to flow. Then, these detected values of currents are compared with the preset values of maximum and minimum currents. A failure is determined when the detected maximum value of current is more than the present maximum value of current or the detected minimum current is less than the preset minimum value of current.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load failure determination device used in a facsimile machine, a digital copying machine, a laser printer or the like.

[0002]

2. Description of the Related Art As a load failure determination device, for example,
The one described in Japanese Examined Patent Publication No. 7-99897 is known. As shown in FIG. 9, a plurality of loads 21 2, 22 3, 23, ... 2n are connected to a DC power source 1 through transistors 31 32 32 33 ... 3n, respectively, and a resistor 4 is commonly connected. ing. Then, the CPU 5 is provided,
The CPU 5 drives the driver 6 so that the driver 6 turns on each of the transistors 31, 32, 33, ... 3n. In addition, the voltage across the resistor 4 is A
The / D converter 7 converts it into digital data and the CPU 5 takes it in. The CPU 5 also displays the display 8
Is controlled.

In this conventional device, the driver 5 is driven by the CPU 5 to drive the transistors 31 32 32 33 ... 3n.
Is turned on, and at that time, each load 21 2, 22 2, 23, ...
The total current flowing through 2n is detected by the resistor 4, the voltage across the resistor 4 is converted into digital data by the A / D converter 7, and the data is fetched by the CPU 5. Then, the CPU 5 obtains the total current value from the digital data, compares it with the total current value when all preset loads normally operate, and if they are different, the difference is calculated from the difference. The display 8 is designed to judge which load has a disconnection failure.

[0004]

However, in this conventional device, since the load failure is judged from the difference between the preset total current value and the detected total current value, there are two or more identical loads. In this case, there is a problem that it cannot be determined which of the same loads has failed. Further, for example, in a laser printer or the like, there is a dynamic load in which a current value to be energized changes depending on load conditions, such as a high-voltage power supply for supplying a high voltage to a charger or a transfer device or a heater incorporated in a thermal fixing device. If the failure load is determined simply by the difference in the total current value, there is a problem that the failure cannot be correctly determined for a load, such as a dynamic load, in which the current value to be energized changes depending on the load condition, and an incorrect determination is made. Therefore, according to the inventions of claims 1 and 2, it is possible to accurately determine a failure of the load even if there are a plurality of identical loads, and as the load, a static load in which a substantially constant current is applied during operation and a load during operation. Provided is a load failure determination device capable of accurately determining a failure of each load even when there is a mixture of dynamic loads whose current values vary depending on conditions.

[0005]

According to the first aspect of the present invention,
A plurality of loads consisting of a static load that applies a substantially constant current during operation and a dynamic load whose current value changes depending on load conditions during operation; and a current detection unit that detects the value of the current flowing through each load, For static loads, it stores the upper and lower limits of the permissible current for each load, and for dynamic loads, it stores the maximum current value and the minimum current value for each load. The detected current value of the means and the current value of the storage means are compared, and for the static load, depending on whether the detected current value is between the upper limit value and the lower limit value of the applicable permissible current, Judgment means for judging whether each load is normal or abnormal depending on whether the maximum value of the detected current is less than or equal to the corresponding maximum current value and the minimum value of the detected current is greater than or equal to the corresponding minimum current value, and this determination means The load judged as abnormal by Is obtained and output means for outputting to allow al.

According to a second aspect of the present invention, a plurality of loads including a static load that applies a substantially constant current during operation and a dynamic load that changes the value of the current that is applied during operation, and a load for each of these loads. Current detection means for detecting the flowing current value, and for static loads, energize each load in advance and the current value is detected by the current detection means.The upper limit value of the allowable current of each load is based on this detected current value. And the lower limit value is determined and stored.For dynamic loads, the load condition is changed for each load in advance to conduct electricity, the current value is detected by the current detection means, and the maximum value of each load is detected based on this detected current value. The memory means that determines and stores the current value and the minimum current value is compared with the detected current value of the current detection means and the current value of the memory means during normal operation, and the detected current value corresponds to the static load. Between the upper and lower limits of the permissible current Depending on whether or not the maximum value of the detected current is less than or equal to the corresponding maximum current value and the minimum value of the detected current is greater than or equal to the applicable minimum current value, it is determined whether each load is normal or abnormal. It is provided with a judging means for judging and an output means for outputting to notify the load judged to be abnormal by the judging means.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. It should be noted that this embodiment describes a case where the present invention is applied to a laser printer. As shown in FIG. 1, a fan motor 12 which is a static load is connected to a first DC power supply 11 through a transistor 131 and a resistor 141 in series, and a main motor 15 which is a dynamic load is connected to a transistor 133 and a resistor. 143 are connected in series. In addition, the first DC power source 11
In addition, the solenoid 16 which is a static load is connected to the transistor 13
4 and the resistor 144 are connected in series.

An optical system 18, which is a static load, is connected to the second DC power source 17 via a transistor 132 and a resistor 142 in series. A heater 20 that is feedback-controlled by a dynamic load is connected to the AC power supply 19 via a switch circuit 21, and a high-voltage power supply unit 22 that is also feedback-controlled by a dynamic load is connected via a switch circuit 23. The fan motor 12 is a fan motor used for air cooling, the main motor 15 is a motor for driving a photosensitive drum, and the solenoid 1
Reference numeral 6 denotes a solenoid for feeding paper, and the optical system 1
Reference numeral 8 is for driving a polygon motor, the heater 20 is a heater used for thermal fixing, and the high-voltage power supply unit 22 is a power supply for supplying a high voltage to a charging device, a transfer device and the like.

A CPU (microprocessor) 24 constitutes a main body of a control unit, a judgment means and a storage means.
4 drives the driver 25 and controls the display 26 as output means. The driver 25 turns on and off each of the transistors 131 to 134, and at the same time, the switch circuits 21 and 23.
Turns on and off. The heater 2
The current flowing through 0 is detected by the current detection circuit 28 having the current detection coil 27, and the high voltage power supply unit 2
The current flowing in 2 is detected by a current detection circuit 30 including a current detection coil 29. As shown in FIG. 2, each of the current detection circuits 28 and 30 includes a coil 27,
A capacitor C is connected across both ends of the capacitor 29, and a diode D1 is connected in parallel across the capacitor C via a resistor R with the cathode on the side of the resistor R. The cathode of the diode D1 is connected to the anode of another diode D2, and the cathode of the diode D2 outputs a voltage corresponding to the detected current amount of the coil.

Each of the resistors 141 to 144 and each of the current detecting circuits 28 and 30 constitutes a current detecting means. The voltage between both ends of each of the resistors 141 to 144 and each current detecting circuit 2
The output voltages of 8 and 30 are supplied to the analog switch circuit 31. The analog switch circuit 31 is the CPU
24, and selectively outputs the voltage across both ends of each of the resistors 141 to 144 and the output voltage of each current detection circuit 28, 30 to A /
It is adapted to be supplied to the D converter 32. A / D
The converter 32 converts the input voltage into digital data and supplies it to the CPU 24.

The CPU 24 determines the current of the fan motor 12, the current of the optical system 18, the current of the main motor 15, the current of the solenoid 16, the heater 20, and the heater 20. The current determination processing of the high voltage power supply unit 22 is performed respectively. As shown in FIG. 3, the current determination process of the fan motor 12 is performed by the transistor 131
Is turned on to turn on the fan motor 12, and in S2,
By controlling the analog switch 31, the voltage across the resistor 141 is fetched from the A / D converter 32 as digital data to obtain the current value I1. Then, in S3, the upper limit value I1max and the lower limit value I1min of the permissible current when the fan motor 12 set in advance in the internal memory operates normally are read out and compared with the detected current value I1. If I1min≤I1≤I1max For example, it is determined that the fan motor 12 is operating normally, and this processing ends. Also, I1 <I1min or I1max <I1
If so, the operation of the fan motor 12 is stopped and an abnormality is determined in S4.

In the current determination process of the optical system 18, as shown in FIG. 4, the transistor 132 is turned on to turn on the optical system 18 in S11, and the analog switch 31 is controlled to switch the resistance in S12. The voltage between both ends of 142 is fetched as digital data from the A / D converter 32, and the current value I
Get 2 Then, in S13, the upper limit value I2max and the lower limit value I2min of the permissible current when the optical system 18 previously set in the internal memory is normally operated are read out and compared with the detected current value I2. If I2min≤I2≤I2max For example, it is determined that the optical system 18 is operating normally, and this processing ends. Also,
If I2 <I2min or I2max <I2, in S14,
The operation of the optical system 18 is stopped and an abnormality is determined.

The current determination process of the main motor 15 is as follows.
As shown in FIG. 5, in S21, the transistor 133 is turned on to turn on the main motor 15, and in S22,
Start the built-in timer. And S23
At, the load condition is changed so that the maximum current flows, and the analog switch 31 is controlled to capture the voltage across the resistor 143 from the A / D converter 32 as digital data to obtain the maximum current value Immax. In S24, the load condition is changed so that the minimum current flows, and the analog switch 31 is controlled to capture the voltage across the resistor 143 from the A / D converter 32 as digital data to obtain the minimum current value Immin. . Then, in S25, the minimum current value I3min when the main motor 15 preset in the internal memory operates normally and the detected minimum current value Immin are compared,
If I3min ≦ Immin, then in S26, the maximum current value I3max set in advance in the internal memory when the main motor 15 operates normally and the detected maximum current value Immax are compared, and Immax ≦ I3max For example, it is determined that the main motor 15 is operating normally, and this processing ends. If Immin <I3min or Immax> I3max, S2
At 7, the operation of the main motor 15 is stopped and an abnormality is determined.

In the current judging process of the solenoid 16, as shown in FIG. 6, in S31, the transistor 134 is turned on to turn on the solenoid 16, and in S32, the analog switch 31 is controlled to turn on the resistor 144. The voltage between both ends is taken in from the A / D converter 32 as digital data,
Obtain the current value I4. Then, in S33, the upper limit value I4max and the lower limit value I4min of the permissible current when the solenoid 16 preset in the internal memory operates normally are read out and compared with the detected current value I4. If I4min≤I4≤I4max It is determined that the solenoid 16 is operating normally, and this processing ends. If I4 <I4min or I4max <I4, the operation of the solenoid 16 is stopped and an abnormality is determined in S34.

In the current determination process of the heater 20, as shown in FIG. 7, the switch circuit 21 is turned on to turn on the heater 20 in S41, and the built-in timer is started in S42. Then, in S43, the load condition is changed so that the maximum current flows, the analog switch 31 is controlled, and the output voltage of the current detection circuit 27 is fetched from the A / D converter 32 as digital data to obtain the maximum current value Ihmax. obtain. In S44, the load condition is changed so that the minimum current flows, and the analog switch 31 is controlled to output the output voltage of the current detection circuit 28 to the A / D converter 32.
Captured as digital data from the
Get. Then, in S45, the minimum current value I5min when the heater 20 set in the internal memory in advance operates normally
And the detected minimum current value Ihmin are compared, and I5min ≦ Ihmin
If so, then in step S46, the maximum current value I5m when the heater 20 preset in the internal memory operates normally
The maximum current value Ihmax detected is compared with ax and Ihmax ≤ I5m
If it is ax, it is determined that the heater 20 is operating normally, and this processing ends. Also, Ihmin <I5min or Ihmax
If> I5max, the operation of the heater 20 is stopped and an abnormality is determined in S47.

In the current determination process of the high voltage power source unit 22, as shown in FIG.
Is turned on to turn on the high-voltage power supply unit 22, and S52
At, start the built-in timer. And
In S53, the load condition is changed so that the maximum current flows, and the analog switch 31 is controlled to control the current detection circuit 30.
The output voltage of is fetched as digital data from the A / D converter 32, and the maximum current value Ivmax is obtained. Further, in S54, the load condition is changed so that the minimum current flows, the analog switch 31 is controlled, and the output voltage of the current detection circuit 30 is fetched as digital data from the A / D converter 32 to obtain the minimum current value Ivmin. obtain. Then, in S55, the minimum current value I6min when the high-voltage power supply unit 22 set in the internal memory in advance operates normally and the detected minimum current value Ivmin are compared. If I6min ≦ Ivmin, then S6
At 56, the maximum current value I6max when the high-voltage power supply unit 22 previously set in the internal memory operates normally is compared with the detected maximum current value Ivmax. If Ivmax ≦ I6max, the high-voltage power supply unit 22 operates normally. If it is determined that this is the case, this process ends. Also, if Ivmin <I6min or Ivmax
If> I6max, in S57, high-voltage power supply unit 22
Stop the operation of and determine the abnormality.

In such a configuration, the upper limit value I1max of the permissible current when the fan motor 12 operates normally,
Lower limit value I1min, upper limit value I2max and lower limit value I2min of allowable current when the optical system 18 operates normally, main motor 15
Current value I3min, maximum current value I3max when solenoid operates normally, upper limit value I4max and lower limit value I4min of allowable current when solenoid 16 operates normally, minimum current value I5min when heater 20 operates normally The maximum current value I5max and the minimum current value I6min and the maximum current value I6max when the high-voltage power supply unit 22 operates normally are set in the internal memory of the CPU 24 by performing a test at the time of inspection by the manufacturer, for example.

That is, the fan motor 1 which is a static load
2. Regarding the optical system 18 and the solenoid 16, each load is energized for a short time to detect a current value, and the upper limit value and the lower limit value of the allowable current of each load are determined and stored based on the detected current value. To do. Specifically, the CPU 25 causes the driver 25 to
To turn on the transistor 131 for a short time,
The voltage across the resistor 141 at this time is taken into the CPU 24 as digital data from the analog switch 31 through the A / D converter 32, and the CPU 24 determines when the fan motor 12 operates normally based on the current value at this time. The upper limit value I1max and the lower limit value I1min of the allowable current are stored in the internal memory.

Further, the CPU 24 drives the driver 25 to turn on the transistor 132 for a short time, and the voltage across the resistor 142 at this time is changed to the analog switch 3
1 to the CPU 24 as digital data via the A / D converter 32, and the CPU 24 internally sets the upper limit value I2max and the lower limit value I2min of the permissible current when the optical system 18 operates normally based on the current value at this time. Store in memory. In addition, the driver 24 is driven by the CPU 24 to turn on the transistor 134 for a short time.
The voltage between both ends of 4 4 is fetched from the analog switch 31 as digital data into the CPU 24 through the A / D converter 32, and the CPU 24 determines the upper limit value of the permissible current when the solenoid 16 operates normally based on the current value at this time. I4ma
Store x and the lower limit value I4min in the internal memory.

The main motor 15, which is a dynamic load,
Regarding the heater 20 and the high-voltage power supply unit 22, the load condition is changed for each load to perform energization to detect the current value, and the maximum current value and the minimum current value of each load are determined based on the detected current value. Remember. Specifically, the CPU 24 drives the driver 25 to turn on the transistor 133 for a certain period of time to change the load condition so that the maximum current and the minimum current flow, and the voltage across the resistor 143 at this time is changed to the analog switch 31. From the A / D converter 32 into the CPU 24 as digital data,
4 stores the maximum current value I3max and the minimum current value I3min when the main motor 15 operates normally on the basis of the maximum current value and the minimum current value at this time in the internal memory.

Further, the CPU 24 drives the driver 25 to turn on the switch circuit 21 for a certain period of time to change the load condition so that the maximum current and the minimum current flow.
The output voltage of the current detection circuit 28 at this time is taken into the CPU 24 as digital data from the analog switch 31 via the A / D converter 32, and the CPU 24 causes the heater 20 to operate normally based on the maximum current value and the minimum current value at this time. The maximum current value I5max and the minimum current value I5min during the operation are stored in the internal memory. The CPU 24 drives the driver 25 to turn on the switch circuit 23 for a certain period of time to change the load condition so that the maximum current and the minimum current flow, and the output voltage of the current detection circuit 30 at this time is changed from the analog switch 31. The data is taken into the CPU 24 as digital data via the A / D converter 32, and the CPU 24 uses the maximum current value and the minimum current value at this time as the maximum current value I6max and the minimum current value when the high-voltage power supply unit 22 operates normally. Store I6min in internal memory.

When the user who purchased the device uses it, for example, the failure judgment of each load is performed when each load is operating. That is, regarding the fan motor 12, when the transistor 131 is turned on to operate the fan motor 12, the analog switch 31 is controlled to control the resistance 1
The voltage across 41 is fetched as digital data from the A / D converter 32 to obtain the current value I1. Then, the upper limit value I1max and the lower limit value I1min of the allowable current stored in the internal memory
Is read and compared with the detected current value I1, I1min≤I1≤I
If it is 1max, it is determined that the fan motor 12 is operating normally. If I1 <I1min or I1max <I1, stop the operation of the fan motor 12 and judge the abnormality,
The display 26 informs the user of the determination result.

Regarding the optical system 18, when the transistor 132 is turned on to operate the optical system 18,
By controlling the analog switch 31, the voltage across the resistor 142 is fetched from the A / D converter 32 as digital data to obtain the current value I2. Then, the upper limit value I2max and the lower limit value I2min of the allowable current stored in the internal memory are read and compared with the detected current value I2. If I2min≤I2≤I2max, it is determined that the optical system 18 is operating normally. If I2
If <I2min or I2max <I2, the operation of the optical system 18 is stopped to determine an abnormality, and the result of the determination is notified to the user by the display 26.

Regarding the main motor 15, the transistor 133 is turned on to operate the main motor 15 and the timer is started. In this state, the load condition is changed so that the maximum current flows, and the analog switch 31 is controlled. Then, the voltage across the resistor 143 is fetched as digital data from the A / D converter 32 to obtain the maximum current value Immax. After a certain period of time, the load condition is changed so that the minimum current flows, and the analog switch 31 is controlled to capture the voltage across the resistor 143 from the A / D converter 32 as digital data to obtain the minimum current value Immin. Then, the minimum current value I3min stored in the internal memory is compared with the detected minimum current value Immin, and the maximum current value I3max is compared with the detected maximum current value Immax to obtain I3min.
If ≦ Immin and Immax ≦ I3max, it is determined that the main motor 15 is operating normally. If Immin
When <I3min or Immax> I3max is determined, the operation of the main motor 15 is stopped to determine an abnormality, and the display 26 notifies the user of the determination result.

Regarding the solenoid 16, when the transistor 13 4 is turned on and the solenoid 16 is operated, the analog switch 31 is controlled to capture the voltage across the resistor 144 as digital data from the A / D converter 32. , Current value I4 is obtained. Then, the upper limit value I4max and the lower limit value I4min of the permissible current stored in the internal memory are read and compared with the detected current value I4. If I4min≤I4≤I4max, the solenoid 16 is determined to be operating normally. If I4 <I4 min or I4 max <I4, the operation of the solenoid 16 is stopped to determine the abnormality, and the display 26 notifies the user of the determination result.

Regarding the heater 20, the switch circuit 21 is turned on to operate the heater 15 and the timer is started. In this state, the load condition is changed so that the maximum current flows, and the analog switch 31 is controlled. The output voltage of the current detection circuit 28 is fetched as digital data from the A / D converter 32 to obtain the maximum current value Ihmax. After a lapse of a fixed time, the load condition is changed so that the minimum current flows, the analog switch 31 is controlled, and the output voltage of the current detection circuit 28 is fetched as digital data from the A / D converter 31 to obtain the minimum current value Ihmin. . Then, the minimum current value I5min stored in the internal memory is compared with the detected minimum current value Ihmin, and the maximum current value I5max
And the detected maximum current value Ihmax are compared, and I5min ≦ Ihmin
If Ihmax ≦ I5max, it is determined that the heater 20 is operating normally. If Ihmin <I5min or I
When hmax> I5max is determined, the operation of the heater 20 is stopped to determine an abnormality, and the determination result is notified to the user by the display 26.

Regarding the high-voltage power supply unit 22,
The switch circuit 23 is turned on to operate the high-voltage power supply unit 22.
And the timer is started, the load condition is changed so that the maximum current flows in this state, and the analog switch 31 is controlled to capture the output voltage of the current detection circuit 30 from the A / D converter 32 as digital data. ,
Obtain the maximum current value Ivmax. After a lapse of a certain time, the load condition is changed so that the minimum current flows, the analog switch 31 is controlled, and the output voltage of the current detection circuit 30 is fetched as digital data from the A / D converter 32 to obtain the minimum current value Ivmin. . Then, the minimum current value I6min stored in the internal memory is compared with the detected minimum current value Ivmin, and the maximum current value I6max is compared with the detected maximum current value Ivmax. If I6min ≦ Ivmin and Ivmax ≦ I6max It is determined that the high voltage power supply unit 22 is operating normally. If Ivmin <I6min or Ivmax> I6max is determined, the operation of the high-voltage power supply unit 22 is stopped to determine an abnormality, and the display 26 notifies the user of the determination result.

As described above, each load is operated individually, and the fan motor 12, the optical system 18, and the solenoid 1 are operated.
For the static load of 6, when the load is operated individually and the detected current value at that time is compared with the upper limit value and the lower limit value of the allowable current stored in the internal memory, and the value is out of the range of the upper limit value and the lower limit value. To inform the abnormality and inform the main motor 1
5, regarding the dynamic load of the heater 20 and the high-voltage power supply unit 22, the load condition is changed so that the maximum current flows and the minimum current flows for each load, and the detected maximum current value and the detected minimum current at that time are changed. The value is compared with the maximum current value and the minimum current value stored in the internal memory, and when the detected maximum current value is greater than the set maximum current value or the detected minimum current value is less than the set minimum current value. Since the abnormality is determined and notified, the failure of the load can be accurately determined individually regardless of the static load or the dynamic load. Therefore, even if there are a plurality of identical loads, load failures can be individually and accurately determined, and even if static loads and dynamic loads are mixed, load failures can be individually and accurately determined.

Further, the heater 20 and the high-voltage power supply unit 22
Feedback control is performed, but since current detection is performed using the current detection coils 27 and 29, feedback control of the heater 20 and the high-voltage power supply unit 22 is not adversely affected by current detection. It should be noted that although the present embodiment has been described by applying the present invention to a laser printer, the present invention is not necessarily limited to this, and any electric device including a static load and a dynamic load can be used. Can also be applied to. Further, in the present embodiment, the display device is used as the output means for notifying the load of which the abnormality is determined, but the present invention is not limited to this, and it may be a lamp, a printer, or an output circuit for outputting a notification signal to the outside. .

[0030]

As described above, according to the first and second aspects of the present invention, even if there are a plurality of identical loads, the failure of the loads can be accurately determined, and a substantially constant current is applied as the load during operation. Even if there is a static load and a dynamic load in which the value of the current to be applied changes depending on the load conditions during operation, the failure of each load can be accurately determined.

[Brief description of drawings]

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

FIG. 2 is a circuit diagram showing a configuration of a current detection circuit according to the same embodiment.

FIG. 3 is a flowchart showing a fan motor current determination process in the same embodiment.

FIG. 4 is a flowchart showing an optical system current determination process in the same embodiment.

FIG. 5 is a flowchart showing main motor current determination processing in the same embodiment.

FIG. 6 is a flowchart showing a solenoid current determination process in the same embodiment.

FIG. 7 is a flowchart showing a heater current determination process in the same embodiment.

FIG. 8 is a flowchart showing a high voltage power supply unit current determination process in the same embodiment.

FIG. 9 is a circuit configuration diagram showing a conventional example.

[Explanation of symbols]

 12 ... Fan motor 131-134 ... Transistor 141-144 ... Resistor 15 ... Main motor 16 ... Solenoid 18 ... Optical system 20 ... Heater 22 ... High voltage power supply unit 21, 23 ... Switch circuit 24 ... CPU (central processing unit) 26 ... Display 27, 29 ... Current detection coil 28, 30 ... Current detection circuit 31 ... Analog switch

Claims (2)

[Claims] 1. A plurality of loads, which are a static load that carries a substantially constant current during operation and a dynamic load whose current value changes depending on load conditions during operation, and the value of current flowing through each load are detected. A memory for storing the upper limit value and the lower limit value of the permissible current for each load for the current detection means and the static load, and the maximum current value and the minimum current value for the current for the dynamic load. Means for comparing the detected current value of the current detection means with the current value of the storage means, and for the static load, whether the detected current value is between the upper limit value and the lower limit value of the permissible current concerned. Therefore, for a dynamic load, it is determined whether each load is normal or abnormal depending on whether the maximum value of the detected current is less than or equal to the corresponding maximum current value and the minimum value of the detected current is greater than or equal to the corresponding minimum current value. The determining means and the determining means A failure determination device for a load, comprising: an output unit that outputs to notify a load that has been determined to be abnormal. 2. A plurality of loads, which are a static load that conducts a substantially constant current during operation and a dynamic load whose current value changes depending on load conditions during operation, and a current value flowing through each load are detected. Regarding the current detection means and the static load, electricity is supplied to each load in advance, the current value is detected by the current detection means, and the upper limit value and the lower limit value of the allowable current of each load are determined based on the detected current value. For the dynamic load, the load condition is changed in advance for each load to conduct electricity, and the current value is detected by the current detection means.The maximum current value and the minimum value of each load are detected based on the detected current value. A memory means for determining and storing a current value is compared with a detected current value of the current detecting means and a current value of the memory means during a normal operation, and for a static load, an allowable current to which the detected current value corresponds. Is between the upper and lower limits of Therefore, for a dynamic load, it is determined whether each load is normal or abnormal depending on whether the maximum value of the detected current is less than or equal to the corresponding maximum current value and the minimum value of the detected current is greater than or equal to the corresponding minimum current value. An apparatus for determining a failure of a load, comprising: a determining means; and an output means for outputting to inform a load of which an abnormality is determined by the determining means.