Latest servo stabilisers and CVTs are smarter, more energy efficient and have longer life span

- Advertisement -

Today, these products are packed with features like IC controlled circuits, high and low voltage cut-offs for compressor protection, and time delay between shutdown and restart for additional safety to connected equipment. They are also easy to install and operate

By Kartiki Negi

Tuesday, October 07, 2014: Servo stabilisers are very reliable and are known for their durability. They are compact and quite portable; hence, they are suitable for applications like computing, entertainment, aerospace, etc. Constant voltage transformers (CVT), on the other hand, effectively regulate voltage variations, suppress transients and bridge short interruptions/dips.

- Advertisement -

The latest in the market

Both CVTs and servo stabilisers have unique advantages. A servo stabiliser automatically corrects voltage at regular intervals. When supplied with constant voltage, synchronous motors operate very efficiently. They protect expensive equipment from the menace of voltage fluctuations, thus lowering the cost of maintenance.

The advantage of using CVTs is that they are extremely reliable and rugged since they have no moving parts. They are capable of controlling a higher input voltage range at lesser loads, unlike servo stabilisers, which have a fixed controlling range. Stabilisers have relays, which when switched cause the output voltage to be interrupted for a short time. This type of interruption or transient many not be good for computers. In comparison, CVTs ensure a clean, spike-free and controlled output voltage. “CVTs have a very short changeover time and are very smooth, while servo stabilisers are not so smooth, and the impact of this can be easily seen in instruments when voltage is very high or low. There are slight fluctuations and some noise in the instrument, which are easily visible to the naked eye,” says Yogesh Dua, director,

Servo stabilisers: In January 2014, Convergence Power Systems launched the SVX series of servo voltage stabilisers, which range from 1 kVA to 1000 kVA. “Our products in the 1 kVA -5 kVA range have applications in security scanning equipment, medical diagnostic equipment, packing conveyor machines, etc. Our stabilisers ranging from 10 kVA-1000 kVA find application in the domestic, industrial and machinery domains. Faster voltage correction speeds with more precise regulation are the advantages of these designs,” says Sreekumar, director, sales and marketing, Convergence Power Systems Pvt Ltd.

Elent Electronics’ servo voltage stabilisers range from 1 kVA to 50 kVA for single phase stabilisers and 5 kVA to 1000 kVA for three phase stabilisers. These variants offer features such as no output waveform distortion, fast correction of output voltage, automatic voltage-20 V/sec, auto/manual operation facility, high efficiency, etc. “These stabilisers are compact and modular, making it easy to install, operate and service,” says Ramotar Singh, director, Elent Electronics Pvt Ltd.

Cosmostat Industries’ existing servo controlled voltage stabiliser is designed and manufactured as per IS 9815 specifications for stable supply. Its fast correction ratio against quick voltage fluctuations ensures trouble-free operation for high precision electrical and sophisticated electronic equipment. It offers a rate of correction that is greater than 10 to 50 volts/second with an efficiency greater than 97 per cent. With a synchronous motor drive for high reliability, its waveform distortion is zero. It comes with an auto manual selector switch to select the mode the stabiliser needs to work in. In the event of the automatic controls failing, the unit can be used under manual control. Push button switches are used to increase and decrease the output voltage of the servo stabiliser when in manual mode.

Constant voltage transformers: In August 2014, launched its constant voltage AVR, which is used to provide constant output for sensitive instruments and for voltage compensation. It is an IGBT-based system with an isolated transformer that has a very short changeover time compared to servo stabilisers. “Electronic equipment like spectrophotometers, PH-meters, x-ray machines and recorders are all affected by a high mains voltage, whereas refrigerators, deep freezers, incubators and other compressors are affected by a low mains voltage. Industries that run for 24 hours also get affected by voltage fluctuation. So these transformers are used to provide a regulated constant voltage to the devices. This CVT can be used to eliminate high fluctuations in AC supply and provide a constant voltage to the device,” says Yogesh Dua.

Servokon Systems’ existing HT AVR (high tension automatic voltage regulator) stabilises voltage directly on HT 11 kV or 33 kV lines and range upto maximum 5000 kVA. It is used in factories, hospitals, the IT industry, malls, etc. “This product guarantees 99 per cent efficiency; it is a highly reliable product with an expected life of more than 30 years,” says Zakir Hussain, director, Servokon Systems Ltd.

Vertex Power Solutions offers a constant voltage single phase transformer, which uses a tank circuit composed of a high-voltage resonant winding and a capacitor, to produce a nearly constant average output with a varying input. The ferromagnetic approach is preferred because of the lack of active components, and the reliance is on the square loop saturation characteristics of the tank circuit to absorb variations in average input voltage. The ferromagnetic action is a flux limiter rather than a voltage regulator, but with a fixed supply frequency, it can maintain an almost constant average output voltage even as the input voltage varies widely. Besides, the input supply is completely isolated from the output by means of an isolation transformer. This CVT is suitable for various applications like computers, data processing equipment, audio/video equipment, photo processing equipment, bio-medical equipment, telex machines, EPABX systems, fax machines, cash registers, electronic typewriters, etc.

How to choose the right product

There are several specifications one must keep in mind when buying an appropriate servo stabiliser or a CVT. One must make sure that the product has the correct specifications with regard to its rating, technical aspects like output voltage regulation, correction speed, etc.

Before selecting a servo stabiliser, one should ascertain how much power it uses. By taking an inventory of all the essential electrical loads and doing a basic electrical load evaluation, one can get a fair idea of how much power the system needs to produce.

Second, prospective buyers should be aware about the power fluctuation scenario, that is, the minimum and maximum voltage from the main AC supply. In brief, one has to select the input voltage window and the power consumption of the appliance. So, when selecting any stabiliser or CVT, the following aspects need to be checked:

  • Input voltage range

  • Output voltage range

  • KVA rating

  • Type of load: balance/unbalance

  • Type of voltage: balance/ unbalance

  • Type of protection required

  • Type of cooling: Air/oil


  • convergenceFast correction speed

  • Stable voltage

  • Almost zero maintenance

  • Long periods of trouble-free operation



  • elentelectronicsOutput voltage: 230 VAC (single phase) and 400 VAC (three phase)

  • Input range 170 to 270 VAC (single phase) and 300 to 470 VAC (three phase)

  • 1 per cent regulation



  • cosmostatRegulation as high as 1 per cent

  • Voltmeter indicates either input voltage or output voltage

  • Screwdriver adjustment to set the output voltage to the exact specified limit

  • Easily replaceable and serviceable PCB

  • Over load capacity as per IS 6600



  • servokon40 per cent energy savings

  • Almost zero per cent failure

  • Efficiency > 99 per cent

  • Expected life: 30 to 40 years’s AVR CVT

  • upsinverterGalvanic isolation

  • High common and normal

  • mode noise attention

  • Sags, surge and brownout protection

  • Sine wave output (generated by the CVT)

  • Low installation heat output and running costs – maintenance-free

  • High Mean Time Between

  • Failure (MTBF)



  • vertexOverload and short circuit protection

  • Spike rejection capabilities

  • Floating output

  • No semiconductors used

  • No electronic circuits

  • Faster voltage correction compared to servo stabilisers

Electronics Bazaar, South Asia’s No.1 Electronics B2B magazine

- Advertisement -

Most Popular Articles


Please enter your comment!
Please enter your name here
Captcha verification failed!
CAPTCHA user score failed. Please contact us!


Growth Opportunities Connected With The Growing Semicon EcoSystem In India

India must concentrate on electronics products and semiconductor components, as progress in one area reinforces the other. The country can unlock immense economic opportunities...

“Don’t Let Designations Become A Wild Goose Chase”

In his childhood, he possessed just one sweater, meant to last through many winters. He could not join IIT Roorkee because the cost of...

“Capitalise On ‘China Plus Two,’ Where Products With Higher Value Addition Become The Focus”

EPIC Foundation aims to transform India into an electronics hardware product nation by collaborating with governments, universities, design houses, and startups. In a conversation...


Ultraviolette Aims For European And Middle Eastern Expansion

Niraj Rajmohan, Co-Founder and CTO of Ultraviolette stated that 2024 is set to mark the company’s foray into international markets while simultaneously strengthening its...

Chargeup’s Goal: 25,000 Drivers In 17 Cities By 2025, Prioritizing Smaller Cities

Chargeup, the forefront battery financing and comprehensive EV asset management platform in India, is on a mission to integrate 100,000 drivers within the upcoming...

Ampere Nexus, Electric Scooter Launching April 30th

Greaves Electric Mobility’s Nexus, having recently traversed the distance from Kashmir to Kanyakumari, is set to be the brand’s inaugural luxury electric scooter and...

Important Sectors

Ultraviolette Aims For European And Middle Eastern Expansion

Niraj Rajmohan, Co-Founder and CTO of Ultraviolette stated that 2024 is set to mark the company’s foray into international markets while simultaneously strengthening its...

Ampere Nexus, Electric Scooter Launching April 30th

Greaves Electric Mobility’s Nexus, having recently traversed the distance from Kashmir to Kanyakumari, is set to be the brand’s inaugural luxury electric scooter and...

Ford Investes In Expanding EV Software Capabilities At Chennai Hub

Ford Business Solutions India, presently with a staff of 12,000, is poised to expand by an additional 3,000 employees. Ford, recognized for its efforts...
solar panels

Tata Power Solar And Indian Bank Forge Partnership To Propel Residential Solar Adoption

This collaboration aims to facilitate easy access to financing for homeowners, setting the stage for a greener future. Tata Power Solar Systems Limited (TPSSL) has...

Log 9 Enters EV Asset Management Via Amphion

Commercial electric vehicle asset management and finance is becoming one of India's biggest emerging business opportunities. Here's Log 9 joining the segment! Log 9 has...


Honda plans major EV factory construction in Canada,

Honda's dedication to this facility reflects its wider ecological objectives, which include a target to only offer zero-emission vehicles by 2040 and to attain...
Sona Comstar

Sona Comstar Launches Mexico Plant For North American EV Demand

The new facility, established to address the increasing demand for premium driveline solutions for BEVs in North America, will focus on manufacturing differential assemblies...

Sterling Tools Inks MoU With Yongin For EV Components Facility

Sterling Tools announced that this strategic partnership is anticipated to bring in Rs 250 crore in business over the next five years. This collaboration...

Tata Elxsi-Renesas MCU Boosts EV Cost Efficiency And Market Speed

The Motor Control Unit's modular, scalable design facilitates integration across various EV applications, reducing time to market by 40%, lowering design and development costs...

Ramkrishna Forgings To Supply Powertrain Parts To Top US Electric Carmaker

Indian producer of rolled, forged, and machined products enter the US electric vehicle market for the first time. Ramkrishna Forgings, an Indian supplier of rolled,...