UPS & Inverter FAQs

• Q. What is power?
  • Technically inverter is used to convert D.C. power into A.C. power. The stored power is in D.C. form and so not compatible for the A.C. loads (eg.: - fan, CFL, tube lights, etc.). Inverter here converts the stored power into required form to run the equipments.
• Q. How inverter works?
  • When there is mains supply available, then the system passes it to the load. Simultaneously it also charges the battery (ies) to store the power with the help of inbuilt charger.
    
    As there is a failure of mains supply, the equipments supply is transferred from battery through inverter. Again when mains arrives, the load is again transferred to the mains supply.
• Q. What size of the inverter should be selected?
  • Ans. The size of the inverter should be selected according to the load being used. The following steps should be considered;
    
    Step 1: - Calculate the total wattage of load you will desire to run on the system. For eg., for running fan, bulb, computer etc .(Suppose we calculate 840 Watt).
    
    Step 2: - The total load should be divided by 0.7 (Power factor for low capacity systems) to convert watts into VA. Then we get;
    840 Watts = 1200 VA 0.7
    
    Step 3: - Finally by getting VA, add 10% - 20% extra to the VA and the final system is selected. We need to add this extra load to keep our system on safer side.
    1200 + 120 = 1320 VA
    
    Step 4: - If the fixed rating system is not available, then always choose the higher capacity of the size calculated. Thus Su-vastika makes 1400 VA system and so 1400 VA system is suitable for this load.
• Q. What is transfer time/changeover time?
  • The transfer of the supply is been done from mains to battery according to the mains failure and mains arrival. The time taken to transfer the load’s supply is known as transfer time (changeover time). Inverter has a changeover time of more than 20 milliseconds.
• Q. What is difference between inverter and UPS?
  • UPS (Un-interruptible Power Supply) is a system which provides power supply to the load without any interruption.It is having very less changeover time(3-5 ms). It is preferred in time-critical applications, such as computer, servers, communication systems, etc. As a minor interrupt of supply can cause a great loss, UPS are preferred in this applications.
• Q. How many types of UPS are available?
  • The types of UPS available are;
    
    Offline UPS
    Online UPS
    Line-Interactive UPS
    Home UPS
• Q. What is Offline UPS? How it works?
  • Computers has a SMPS in its CPU. The SMPS is capable to provide supply for 10 milliseconds after the mains failure. Thus if supply arrives within 10 millisecond, then the computer will not re-boot (shut down).
    
    Based on this when an inverter’s changeover time reduces to 10 millisecond, then it can run computer without re-booting it.
    Offline UPS is basically an inverter having changeover time < 10 millisecond.
• Q. What is Online UPS?
  • The true UPS is Online UPS. It provides the power supply at a constant rate without any interruption. The output supply provided is always the supply of the system and no supply is by-passed. Thus there is no transfer of supply and thus it has ‘0’ changeover time. It is applicable in time critical applications;
    
    eg.: -
    Computers
    ATM machines
    Telephone exchanges
    Communication centers
    Servers
    Medical equipments
    Photo-lab machines
    
• Q. Which technology our Online UPS are using?
  • Our Online UPS uses IGBT technology.
• Q. What is Line-Interactive UPS?
  • When an offline UPS is merged with an AVR (Automatic Voltage Regulator),
    Then it is called as Line-Interactive UPS. It has a changeover time of 3-4 milliseconds.
• Q. What is Home UPS (HUPS)?
  • Home UPS is a merged form of offline UPS and inverter. It is selectable in which mode the system is to be run.
• Q. What is the required voltage for HUPS to operate?
  • When HUPS is working in UPS mode, then the minimum voltage should be 180V and maximum voltage should be 250V. When it is working in inverter mode, then the minimum required voltage should be 140V and maximum voltage should be 280V.
• Q. What is microcontroller/DSP based Inverter/UPS?
  • Previously the inverter/UPS were having bulky and big circuitry to operate the system. Later a microcontroller chip was introduced. The large circuitry was reduced by introducing this chip. This chip has a inbuilt programme to make the system run automatically.
• Q. What is digital inverter/UPS?
  • The system having a processor in it is known as digital system. As defined above the system having microcontroller chip is called digital system (inverter/UPS)
• Q. What are the benefits in digital system?
  • By converting the system digital, the large circuit is turned compact and thus’
    The cost reduces.
    It becomes more fast responding
    It becomes more user friendly
    More protections can be added in the system