A. Product Overview

The COSMIC MS 303LI is a three-phase inverter developed for applications that require dependable backup power for medium and high-capacity electrical loads. It accepts power from a battery bank and converts the stored DC energy into a regulated three-phase AC output.

The inverter range is available in ratings from 10 kVA to 100 kVA. It provides selectable output voltages of 380 V, 400 V or 415 V AC with output voltage regulation of approximately 1 percent from no load to full load. Its DSP-based control and IGBT switching architecture help produce a stable PWM sine-wave output suitable for sensitive electrical and electronic equipment.

The COSMIC MS 303LI can be used for flats, bungalows, commercial premises, lifts, elevators, escalators, research laboratories, financial institutions and educational facilities. COSMIC products are manufactured for industrial, commercial and domestic power-management applications.

Key Product Features

• Three-phase input and three-phase output configuration
• Power ratings from 10 kVA to 100 kVA
• DSP-based digital control
• IGBT switching technology
• PWM sine-wave output
• Output voltage options of 380 V, 400 V and 415 V AC
• Output voltage regulation of approximately 1 percent
• Frequency stability of 50 Hz with approximately 0.1 Hz variation
• Inverter efficiency above 93 percent
• Output power factor of 0.8
• Total harmonic distortion below 3 percent
• Crest factor of 3:1
• Inbuilt copper or aluminium isolation transformer
• LCD, digital or LED metering options
• Tubular or inverter battery compatibility
• Fan-cooled enclosure
• IP20 panel protection
• Digital monitoring of input, output, battery, load and fault conditions
• Protection against overload, short circuit, voltage variation and mains single phasing

These features are based on the manufacturer’s published three-phase inverter specifications.

B. Working Principle

The COSMIC MS 303LI works by converting DC power stored in a battery bank into controlled three-phase AC power.

1. Battery Energy Storage

The inverter is connected to a suitable battery bank. Depending on the selected system configuration, the published specification indicates a DC bus voltage of 360 VDC or 384 VDC, normally using 30 or 32 batteries of 12 V each. Tubular batteries or inverter batteries may be used.

2. DC to AC Conversion

When backup power is required, DC electricity from the batteries enters the inverter power-conversion section. IGBT switching devices convert this DC supply into an AC waveform.

3. DSP-Based Output Control

A digital signal processor continuously manages the switching pattern, output voltage, frequency and phase relationship. This control helps the inverter generate a regulated three-phase PWM sine-wave output.

4. Isolation Transformer

The inbuilt isolation transformer provides electrical isolation between the inverter’s power-conversion section and the connected load. It also helps deliver the required three-phase output voltage.

5. Three-Phase Power Supply

The inverter supplies three-phase output with neutral and earth connections. The three output phases maintain approximately 120-degree phase displacement for balanced operation of suitable three-phase equipment.

6. Monitoring and Protection

The digital display can indicate input and output voltages, output current, frequency, DC voltage, battery percentage, load percentage and fault conditions. The protection system monitors overload, short circuit, output under-voltage, output over-voltage, DC voltage variation, mains voltage variation and mains single phasing.

C. Why It Is Used

Reliable Three-Phase Backup Power

Many commercial and industrial installations operate on three-phase electrical power. A normal domestic inverter cannot support these loads. The COSMIC MS 303LI provides a three-phase output for suitable high-capacity applications.

Protection Against Power Interruptions

Unexpected power failures can stop lifts, laboratory equipment, office infrastructure, communication systems and other essential operations. A properly sized inverter and battery bank provide temporary backup power during such interruptions.

Stable Sine-Wave Output

The PWM sine-wave output helps operate sensitive electrical and electronic equipment more safely than an unregulated or square-wave power source.

Support for High-Capacity Loads

The 10 kVA to 100 kVA capacity range allows the inverter to support different load requirements in buildings, institutions and industrial facilities.

Electrical Isolation

The inbuilt isolation transformer provides separation between the inverter circuitry and connected equipment. This is useful in installations where isolated power is required for operational reliability.

Centralised Power Backup

Instead of using multiple small inverters, one properly selected three-phase inverter can support a group of approved loads through a central battery backup system.

Monitoring of System Conditions

The digital metering system allows operators to monitor electrical values, battery condition, load percentage and faults from the inverter panel.

Protection of Connected Equipment

The built-in protections help safeguard the inverter and connected loads against overload, short circuit, abnormal output voltage, abnormal DC voltage and mains-related disturbances.

D. Suitable Buyers

Lift and Elevator Contractors

The inverter may be considered for lifts, elevators and escalators where three-phase backup power is required. Final selection must consider motor rating, starting current, operating sequence, regenerative characteristics and required backup duration.

Commercial Building Owners

Suitable for offices, shopping facilities, hotels, corporate buildings and commercial premises that require centralised three-phase backup power.

Residential Societies and Large Homes

Can be considered for apartment buildings, residential societies, flats and bungalows with higher backup requirements and three-phase electrical distribution.

Educational Institutions

Suitable for schools, colleges, universities, laboratories, computer centres and administrative buildings requiring dependable backup power.

Financial Institutions

Banks, insurance offices and financial organisations can use a three-phase inverter to support critical electrical and operational infrastructure.

Research Laboratories

Suitable for approved laboratory equipment, instruments, environmental systems and support infrastructure after proper load assessment.

Hospitals and Healthcare Facilities

The inverter may support eligible non-life-critical hospital infrastructure and approved equipment. Medical applications must be evaluated according to equipment safety requirements and applicable electrical standards.

Industrial Users

Manufacturing facilities, workshops and industrial plants can use the inverter for suitable control systems, lighting, communication equipment and approved machinery.

Government and Corporate Organisations

COSMIC supplies power-management solutions for government organisations, industrial equipment, telecom, data centres, hospitals, hotels, banking, financial institutions, corporate sectors and small and medium businesses.

Frequently Asked Questions

1. What is the COSMIC MS 303LI?

The COSMIC MS 303LI is a high-capacity three-phase inverter designed to convert battery DC power into a regulated three-phase AC output for residential, commercial and industrial backup applications.

2. What is the capacity range of the COSMIC MS 303LI?

The published three-phase inverter range is available from 10 kVA to 100 kVA.

3. Does the inverter provide three-phase output?

Yes. It provides three-phase output with neutral and earth connections.

4. What output voltages are available?

The published output voltage options are 380 V, 400 V and 415 V AC three-phase. The specified output voltage regulation is approximately 1 percent from no load to full load.

5. Which technology is used in the inverter?

The inverter uses DSP-based control, IGBT switching and PWM sine-wave output technology.

6. What is the efficiency of the COSMIC three-phase inverter?

The published inverter efficiency is above 93 percent. Actual operating efficiency may vary according to load level, battery condition, installation and environmental conditions.

7. Does it have an isolation transformer?

Yes. The specification lists an inbuilt copper or aluminium isolation transformer. The transformer material should be confirmed when ordering.

8. Which batteries can be used with this inverter?

The inverter is specified for tubular or inverter batteries. The manufacturer lists Exide, Amaron or equivalent battery makes.

9. How many batteries are required?

The published configuration specifies 30 or 32 batteries of 12 V each, corresponding to a 360 VDC or 384 VDC battery bank. The exact configuration depends on the selected inverter capacity and design.

10. How long does the battery take to recharge?

The published recharge time is up to approximately 12 hours for full capacity. Actual charging time depends on battery capacity, discharge level, battery age and charger rating.

11. What information is shown on the digital display?

The display can indicate R, Y and B input and output voltages, output current, frequency, DC voltage, battery percentage, load percentage and fault conditions.

12. What protections are included?

The inverter provides protection against:

• Output overload
• Output short circuit
• Output under-voltage
• Output over-voltage
• DC under-voltage
• DC over-voltage
• Mains under-voltage
• Mains over-voltage
• Mains single phasing

13. Can the COSMIC MS 303LI be used for lifts and elevators?

Yes, lifts, elevators and escalators are listed among its applications. However, inverter sizing must consider motor power, starting current, acceleration, operating frequency and emergency travel requirements.

14. Can it operate motors and industrial machinery?

It may be used with compatible three-phase loads, but motor and machinery applications require detailed load analysis. The continuous rating, starting current, operating power factor and peak demand must be checked before selecting the inverter.

15. What overload capacity does the inverter provide?

The published specification indicates approximately 110 percent overload for five minutes and 150 percent overload for 60 seconds without bypass.

16. Does the inverter include a bypass switch?

The published specification identifies the standard configuration as being without a bypass switch. Any external or optional bypass requirement should be confirmed before ordering.

17. What is the output waveform?

The inverter provides a PWM sine-wave output with published total harmonic distortion below 3 percent.

18. What is the enclosure protection rating?

The inverter panel has a published protection rating of IP20 and is intended for indoor installation.

19. What environmental conditions are recommended?

The published operating conditions specify an ambient temperature range of approximately 5 degrees Celsius to 40 degrees Celsius, humidity up to 95 percent relative humidity and altitude below 1,000 metres above mean sea level.

20. What details are required to select the correct inverter?

The following information should be provided:

• Total connected load in kW or kVA
• Type of connected equipment
• Motor or lift starting current
• Required input and output voltage
• Required backup duration
• Battery type preference
• Existing battery bank details
• Load power factor
• Installation location
• Ambient temperature
• Future load expansion
• Required quantity

21. How should the inverter capacity be selected?

Capacity should be selected after calculating the total running load, starting load, load power factor, future expansion and required safety margin. Motor, lift and transformer loads normally require additional capacity because of their starting current.

22. Who should install the inverter?

Installation, battery connection, earthing, cabling and commissioning should be completed by qualified electrical personnel. The manufacturer specifies solid chemical earthing for the installation.

Specification note: The current COSMIC product catalogue identifies the three-phase inverter as the MS 303LI, while the detailed technical page on the manufacturer’s associated Multinet Systems website displays the model code MS 301LI. The model number and final technical datasheet should therefore be confirmed before publishing specifications or issuing a quotation.