Detailed analysis of UPS failure causes

Below we list in detail the factors that affect UPS operation:

Battery

According to data analysis, among the UPS returned for repair, the proportion of UPS not working properly due to battery failure is about one-third. Therefore, we should pay special attention to whether the battery is faulty.

There are several types of faults caused by battery problems:

1. The UPS cannot start.

Because Smart-UPS is started by DC, it cannot start when there is no battery connected, the battery is low or there is a problem with the battery. There are several similar situations below:

The first situation: The newly installed UPS cannot start.

If the UPS is a SUA1000ICH model, please check whether the battery connection plug on the rear panel of the UPS is connected. If it is a rack-mounted UPS such as SU3000RMI3U, please open the front panel to check whether the battery is connected.

Since new batteries will self-discharge during storage, the UPS cannot start when the battery is in a low-power state. At this time, you need to connect the UPS to the battery and the mains, and press the Test button on the front panel of the UPS. Although the UPS panel display light will not light up, the UPS will charge the battery. After charging for a period of time, press the test button again and the UPS will start working.

The second situation: After the UPS inverter has been working for a period of time, the UPS cannot start.

Also because the battery is low, it needs to be charged.

The third situation: The battery has been used for about 2 years and the UPS cannot start.

According to the usage of most customers, the battery will generally have a capacity reduction problem to a greater or lesser extent after two years of use. If the battery cannot play the role of delaying the use, it needs to be replaced with a new one.

The fourth situation: The voltage of each battery is normal, but the UPS cannot start.

At this time, although the voltage of a single battery is normal, 1. It is likely that there is a problem with the connection between the batteries or between the battery and the UPS, such as: the connection point is not firm or the connection point is oxidized. At this time, you need to remove the oxide and reconnect. 2. The fuse connecting the UPS and the battery may be broken. If the fuse is broken, just replace it. 3. The connection between the UPS and the battery is very long and thin or there is a connection point in the middle, which produces a large voltage drop, causing the UPS to fail to start.

2. After the mains power is cut off, the UPS cannot switch to inverter mode.

Let the UPS work under the mains power, set the multimeter to the voltage range, connect the test leads to the inside of the Anderson plug on the back of the UPS, and directly measure the DC voltage reaching the UPS. At this time, one person observes the multimeter display, and the other person unplugs the input line of the UPS and observes the multimeter display at the moment of power failure. If the voltage value drops a lot instantly, it means that there is a problem with the battery. If the connection problem can be eliminated and the battery has been used for about two years, it is necessary to consider replacing the battery pack.

3. The UPS inversion time is short and cannot meet customer requirements.

First, the battery parameters of the Smart-UPS long-duration model must be set at the beginning of installation. If the battery parameters are not set, the problem of short inverter time will occur.

Second, the battery parameters have been set, but the UPS inversion time is still very short. You can measure the battery voltage when the UPS low-power alarm sounds. If the measured value shows that the battery is indeed in a low-power state, you need to replace the battery. If the measured value shows that the battery is not in a low-power state, you need to perform a charge and discharge verification. Note that during the charge and discharge verification, the battery must be fully charged and needs to carry about 50% of the load when discharging.

Third, after installing the PowerChutePlus software, the default setting of the software is: the computer will shut down 5 minutes after the mains power is interrupted, so you need to modify the parameters in the software.

Mains power environment

1. Grid interference.

If there is a very serious interference in the power grid, such as voltage sag and other power interference, it may cause UPS to fail and other faults. Below we list some such mains interference. You can install PowerChutePlus software and use the software's event log to understand whether there is power interference in the power grid. If you see a lot of such records in the event log, it means that there is a serious interference in your mains power grid, which will also reduce the service life of the battery. If conditions permit, it is recommended that you replace one mains input or transform the power grid.

PowerChutePlus event logging can record the following mains disturbances:

UPSONbattery: Deepmomentarysag deep voltage sag

UPS on battery: Large momentary spike, deep high voltage pulse

UPSonbattery:Brownout continuous low voltage

UPSonbattery:HighinputLinevoltageHigh input voltage

UPS on battery: Small momentary spike Mild high voltage pulse

UPS on battery: Small momentary sag Mild voltage sag

2. A leakage protector is installed at the UPS input end.

When the UPS is turned on, the leakage protector will trip. If you need to install a leakage protector, you need to connect the leakage protector to the output line of the UPS.

3. The air switch at the UPS input end trips.

This phenomenon may be caused by the small capacity of the air switch at the UPS input end. Since the starting current of the UPS is relatively large, the capacity of the air switch at the front end is required to be large enough.

4. The UPS inverter state and online state are frequently switched.

First, it could be caused by fluctuations in the mains electricity. Second, if you are using a generator, this could happen.

How to do it:

1. Smart-UPS cannot cold start, but can work as an inverter normally.

This is an incorrect operation method. The correct cold start procedure is: press and hold the Test key for about 4 seconds, and release it immediately after hearing a "beep" sound. The UPS can then cold start. If the key is pressed for too long or too short, the UPS cannot cold start. It is recommended that you try this procedure several times.

2. UPS and computer communication is abnormal.

This problem can occur if you are not using an APC original communication cable.

4. Connection method of SU5000UXI, SU5000INET, SU5000RMINET input line.

These three models do not come with input cables when they leave the factory, but they have dedicated input cable terminals. Input cable connection steps: Find the UPS input cable terminal (for SU5000INET, the input cable terminal is at the upper right corner of the back of the UPS, and for SU5000RMINET, it is at the upper left corner of the back of the UPS). It is hidden in the cover, which is fixed by a screw. You need to use a screwdriver to loosen the screw and remove the cover to connect the input line.

5. The fan starts frequently when Smart-UPS is working online.

This situation is caused by the high temperature inside the UPS. You can install PowerChutePlus to observe the internal temperature of the UPS. Generally, the fan starts when the temperature inside the machine reaches 40 degrees Celsius. This design is to improve the service life and operational reliability of the UPS.

Other factors:

1.Smart-UPS often has overload alarm.

Please check whether there is a printer connected to the UPS. It is not recommended to connect the printer behind the UPS, because the working current of the printer will suddenly increase a lot when printing, which may cause the UPS to overload and power off. It is also not recommended to connect the power socket behind the UPS, because the power socket may cause a momentary short circuit and cause the UPS to overload.

2. The LCD display of Matrix5000 and Matrix3000 shows: NoBatteryCommunications

This is because the original SmartCell or SmartCellXR battery pack is not configured. This message only shows "no battery communication" and will not affect the normal operation of the UPS.