Changes of uninterruptible power system

Which generation does your equipment belong to?

Medium- to Large-capacity UPS

Mini UPS

Recommendation of preventive maintenance

reventive maintenance is required to maintain characteristics and performances of UPS.
An UPS is composed with various electronic and electrical parts, and its performance is demonstrated only when all components work properly. Since some of component parts become deteriorated under particular environmental or operational circumstances, a planned parts replacement is necessary.

Example of periodical replacement parts * Medium- to Large-capacity UPS rated 10kVA or more
Replacement period differs depending on UPS series.

■ Parts for periodic replacement

Replacement Cycle Part Impact of failure External shape of the parts (example)
3–5 years Cooling fan Abnormality of a fan causes an increase of inside temperature and a failure stop of an UPS.
5 years Magnetic contactor A grease solidification at moving parts causes a malfunction and errors of uninterruptable switching and operation during a power outage.
7.5 years Control power If the control power becomes abnormal, the unit becomes uncontrollable and the UPS will fail and stop.
Relay unit
Coil breakage caused by constant excitation and contact failure caused by oxidation and corrosion will lead sequence control errors.
Electrolytic capacitor Abnormal destructive puncture due to drop of internal insulation resistance and/or gradual lowering of the capacitance will occur. If abnormal destruction occurs, it leads to DC short circuit and the UPS will fail and stop.
Surge absorber The role of surge absorbers is to prevent intrusion of a lighting surge by releasing it to the ground. There is a risk of wire breakage by corrosion due to surge or moisture absorption in the past.
Fuse An electric current is always flowing through a fuse, and it would cause an aging degradation of internal elements. Also, there is a risk of self-fusion in the end.

■ Example of parts without periodical replacement

Replacement Cycle Part Impact of the failure External shape of the parts (example)

15 years

Controller PCB

If failure has occurred in a part/component, the UPS will fail and stop.

At the time of failure, the bad part/component is replaced.


Semiconductor element

AC capacitor

By category


When a battery has failed, the UPS will stop during a power outage.
Periodical replacement is performed in accordance with the replacement period by category.

MSE-type: 7–9 years
HS-type: 5–7 years
Lead-acid storage battery with small control valve: 4–5 years

Battery instant discharge diagnosis device

We provide a speedy diagnosis while the battery is being charged.

A battery instant discharge diagnosis device (BSC) is a device which diagnoses whether the battery is healthy by short-time discharging per cell during operation.

  1. We provide a diagnosis service while the equipment is in operation.
  2. As the diagnosis is made by short-time discharge (0.5–1.5 sec/1–3C discharge) characteristics:
    • Individual degradation or failure can be detected even from many batteries are connected.
    • We can diagnose about 400 units of batteries in a day.
    • As the diagnosis and verification are made by direct discharging, there is no need for concern even during a power outage.
    • As the amount of discharge for the diagnosis is less than 0.1%, there is no need for concern over capacity decrease.
  3. Our professionals would provide you the diagnosis results including an overall assessment on the spot.
  4. Diagnosis services provided by a qualified person for battery maintenance are safe and certain.
Example of diagnosis data

● Discharge characteristics

Perform a discharge test of all cells, and you can identify the cell with the largest voltage drop, cells of average characteristics and the cell with the smallest voltage drop. (Cells of reduced capacity have significant voltage drops.)

● Voltage graph of all cells

You can check the voltage distribution of all cells by plotting the data on a graph with lines drawn for an attention level and a capacity reduction level defined from the BSC measurement data vs. capacity test.

Utilization example of diagnosis results
  • As a basis of judgment over the Upgrade timing of batteries that are close to end of life
  • As a reasoning data for good cell selection in life-prolonging treatment
  • As a detection tool for early deterioration and/or bad cells
  • As a regular inspection tool of battery systems
Target batteries for diagnosis
Liquid-type lead-acid battery, alkaline battery, sealed lead-acid battery
Battery capacity 20–3000 AH
(support 5000 series for 600 AH or less)
Manufacturer does not matter.
Small batteries for mini UPS and dry batteries are not supported.
Diagnosis service personnel
The diagnosis is conducted by a “Storage battery equipment maintenance qualified personnel” license holder, certified by the Battery Association of Japan.
Major specifications of BSC
Item Specifications
Battery Voltage 1, 2, 4, 6, 8, 12 V
Discharge Current 20–3000 A, arbitrary setting with 1 A step
Data file 250 cells/file
Memory card Compact flash type 1 unit
Communication RS-232C 1 port
Display LCD 40 digit × 4 lines, with backlight
Measurement accuracy Full scale ±1% in each range
Internal resistance Measurable
Drive voltage DC12 V (battery drive)
Drive hours 2 hours or more (after being fully charged for 15 min)
Temp/Humid. 0 to 35°C, 20% to 80%
Weight 4.0 kg (BSC5000i)
Diagnosis execution example

Diagnosis execution example

Outer view of BSC

Outer view of BSC

Outer view of BSC

Unit batteries (36, 46 V) are also supported.

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