Benoit Technologies

What Are Servo Voltage Stabilizers and What are The Technologies Available?

Our devices and appliances are highly susceptible to the adverse effects of unstable voltage. Fluctuations in incoming voltage can cause damage, compromising the performance and longevity of our equipment. Servo voltage stabilizers are essential for protecting machines and electronic equipment from fluctuations in the incoming voltage. 

A voltage stabilizer is a device that maintains a steady state of voltage. Different types of stabilizers are available, depending on the quality and specification of the voltage and the desired stability duration. It is used to maintain a stable voltage quantity in the power system, ensuring a stable power supply and protecting appliances from damage caused by voltage fluctuations. They maintain a constant voltage despite external conditions or changes in incoming voltage. Servo stabilizers are among the best technologies available for voltage stabilization. 

What is Stabilizer?

Voltage fluctuation can cause damage to the load. If there are sudden load changes due to some faults in the power system, voltage fluctuation occurs. There are times when these voltage fluctuations can reduce the life span of any home appliance. So, industries make use of the voltage regulator to ensure that there is a stable supply of voltage to the load and to make sure that there is no or minimal cause of voltage fluctuations. Knowing how important it is to use a voltage regulator to avoid fuse problems, the stabilizer is employed in many commercial applications. 

A stabilizer is a device which is used to maintain a steady state. Depending on the quality and specification of the voltage, there are different types of stabilizers out there to maintain stability for a certain time. In general, the stabilizer used to maintain a stable voltage quantity in the power system is known as a voltage stabilizer. It works when the control element is used to process the unregulated input to the regulated output. 

Voltage Stabilizer

A voltage stabilizer is designed in such a way that it can maintain a stable voltage level to ensure a constant power supply even if there are any changes or fluctuations in the voltage supply to protect the appliances. When a voltage regulator provides a constant voltage level to the home appliances it is called a voltage stabilizer.  The need and importance of this voltage stabilizer are vast and hence it is the most important device in commercial industries. 

There are different types of voltage regulators out there such as electromechanical voltage regulators, automatic voltage regulators, active regulators etc. In the same way, there are various types of voltage stabilizers out there such as automatic voltage stabilizers, DC voltage stabilizers, and AC voltage stabilizers. Let us see how it works exactly.

We can study the working of the voltage stabilizer by analyzing the different types of voltage stabilizers. To maintain a constant level of voltage, a voltage regulator is used. It is a device designed to automatically manage all the constant levels of voltage. There are many types of voltage regulators. For instance, one can be using a feed-forward design approach while the other one can be using negative feedback.

Types of Voltage Stabilizers

There are mainly two types of stabilizers – relay-based voltage stabilizers and servo voltage stabilizers/regulators. Relay-based voltage stabilizers are typically single-phase products used for low-power applications (<5kVA) for television, refrigerator and air conditioners and they can provide voltage There are mainly two types of stabilizers – relay-based voltage stabilizers and servo voltage stabilizers/regulators. Relay-based voltage stabilizers are typically single-phase products used for low-power applications (<5kVA) for television, refrigerator and air conditioners and they can provide voltage regulation from 230 volts±5%. The Servo Stabilizer is used for critical single-phase and three-phase applications from 1 kVA to 3000 kVA and can achieve precise voltage regulation of 230 volts±1%.

Types of Servo Stabilizers

There are two types of servo stabilizers: air-cooled and oil-cooled. Oil-cooled servo stabilizers are the ideal electrical devices for perfect voltage conditioning. These stabilizers offer spectacular functions and features, making them a popular choice for industries in the region.

The two main types of stabilizers are relay-based voltage stabilizers and servo voltage stabilizers/regulators. Relay-based voltage stabilizers are typically used for low-power applications, while servo voltage stabilizers are ideal for critical single-phase and three-phase applications. Servo stabilizers can achieve precise voltage regulation of 230 volts±1%.

Importance of Servo Stabilizers 

The voltage stabilizers become mandatory for office, commercial and industrial use. They protect any machine and electronic equipment from voltage fluctuations. They maintain constant voltage regardless of changes in the incoming voltage and the external conditions. There are many technologies used for stabilisation, and the servo type is the best one out of it. Servo stabilizers vary based on the range of input voltage tolerance and output stabilisations.

Servo stabilizers have become prominent everywhere nowadays. Earlier, there used to be individual voltage stabilizer systems to protect a particular device from voltage fluctuations.

Oil-cooled servo stabilizers are the ideal electrical devices used to enable perfect voltage conditioning. These stabilizers have spectacular functions and features – if you are in search of the right voltage stabilizer, then you should definitely understand the uses and applications of oil-cooled servo voltage stabilizers.

However, the latest technology of the voltage stabilizer is a servo stabilizer as of now. Knowing how important it is to get one quality servo stabilizer for industrial purposes, we come up with a detailed guide for servo stabilizers.

Servo Voltage Stabilizers and their Applications

No electricity board in India can ensure constant voltage to the customers. Voltage is typically low during daytime and high during night hours. Moreover on holidays, peak hours, rainy days and when the agricultural and industrial loads are switched off the voltage arises sharply, which creates problems for the machinery resulting in financial loss.

90% of the industrial load consists of motors. In electric motors of smaller capacity up to 7.5 HP, during low voltage, the motor draws higher current which requires a higher setting of overload relay to avoid the frequent tripping of motors. The higher setting of the overload relay has a very less safety margin against single phasing and mechanical faults. Suppose the relay setting is 15 to 20 % higher than the actual operating current, then the relay will take 46 minutes to trip. The motor cannot withstand the high current for such a long time and in most cases, it burns out before the motor trip. Servo stabilizers are meant to overcome all the above problems by maintaining a constant level of voltage irrespective of the fluctuating mains power supply system

A servo stabilizer is a system, which provides stable Alternate Current (AC) output voltage where the input power supply voltage changes drastically. It protects costly equipment from high and low voltage problems. It also increases the life of the equipment and the productivity of machinery and reduces wastage and damage of raw materials by providing a stable electric supply. The name servo is related to the type of motor, which is used to enable the voltage correction (by using the servo motor and variac with a buck-boost transformer.)

This type of stabilizer assures stable output power supply, and protection from low voltage, high voltage, overload, and short-circuiting.

Applications of Servo Voltage Stabilizers

The Servo Voltage Stabilizers are widely used in engineering units, pharmaceutical units, cold storage, air conditioning plants, offset printing machines, textile mills, cement plants, flour mills, oil industries, paper mills, rubber industries, tea estates, food processing units, oil and Vanaspati plants, footwear units, distilleries and beverages, clubs, hotels, multistoried buildings, hospitals, nursing homes, export houses and call centres.

Advantages of using Servo Voltage Stabilizers:

  • Protects the life of the equipment from severe voltage fluctuations
  • Provides regulation with overall energy saving (98+% efficiency)
  • No consumables are needed
  • Improvement in quality of goods
  • Increased production by reducing the manufacturing of defective items
  • Better safety and protection
  • Fewer breakdowns
  • Uniform quality of end products

Components of Stabilizer

Here are the main components of stabilizers that make them work effectively.

  • Dimmer
  • Buck Boost Transformer
  • Carbon brush
  • Servomotor
  • Carbon brush
  • Contactor


Dimmer is a variable transformer that is usually round in shape. It is made of CRGO toroidal core, which is used to adjust the turn ratio to the desired capacity. The dimmer is specially designed with care and attention as it is used to either increase or decrease the voltage which enters the buck-boost transformer. With this incredible device, the output voltage level can either be increased or decreased up to 50% only.

For instance:  if the given input voltage of the transformer is 160V, the dimmer will increase it to at least 190Volt.  The load will be balanced by the buck-boost transformer.

Buck-Boost Transformer

While testing the servo stabilizer, some kind of insulating vanish called transformer to vanish is applied over the windings that are to be used in the buck-boost transformer.  This varnish saves windings in the transformer from any kind of external disturbance and environmental exposure. If it fails to use varnish, coils could get damaged due to heavy vibrations inside.


From the name itself, we can be clear that the servomotor is the essential part of a servo stabilizer. There is a synchronizing motor in the servomotor which has motors that rotate the arm mounted on the dimmer either clockwise or anti-clockwise as per the input voltage.

Carbon Brush

The carbon brush is a moving part in these servo stabilizers, which is well-fitted in the shaft so that it can contact with the dimmer.  It is essential for the servo stabilizer manufacturer to get good quality brushes as the carbon brush will disappear early if the voltage variation is frequent.


 A contactor is generally used to cut down the output of any servo stabilizer when it exceeds the threshold limit.


MCCB is used to balance the overload while MCB is used to give short circuit protection.

Electronic Circuit

It is no wonder that an electrical device needs an electronic circuit to process the thing. In a stabilizer, an electric circuit sends the signal to some parts of the stabilizer like a dimmer, motor etc. The device works as per the signal that passes around the electric circuit.

Working of Servo Stabilizer or Stabilizer

It is extremely easy to understand the working principle of a servo stabilizer.  There is the main control circuit which contains a microprocessor that controls the action. When the main circuit receives the input from the automatic voltage regulator, the signal sends feedback to the main control circuitry. The microprocessor continuously receives input voltages. If there are any fluctuations in the input voltage, the regulator induces the microprocessor to give more triggers to the motor driver.  The number of auto windings at the transformer can be increased or decreased based on the servo motor. So voltage flows to the buck-boost transformer. 

The servo motor shaft is mounted on the buck-boost transformer. So, if there is any change in the voltage level across the primary coil of the buck-boost transformer it results in the change of input level in the secondary coil. The servo motor moves in a perfect way so that the proper voltage can be observed at the primary coil of the buck-boost transformer. The output voltage of the servo stabilizer is the voltage across the secondary coil of the buck-boost transformer. This process takes place until it achieves the correct input voltage.

Generally, the three phases of the automatic voltage regulator are independent phase controlled. It is much like the single-phase servo stabilizer.

In order to control the motorized variable transformer, the servo stabilizer uses an advanced servo motor concept. As it follows motorization, there is a delay in the voltage corrections. When input voltages change up to +50%, the output voltage would be +1%.  Even if there is voltage fluctuations or frequency variation, the servo motors won’t be damaged. This working principle works well for all the three phases such as line to line, line to neutral etc. irrespective of load balance and voltage balance. The device is designed in such a way that it can withstand external conditions and large inrush currents, voltage fluctuations etc.  Despite the latest technology, these kinds of servo stabilizers required good & regular maintenance.  It follows different design topologies.

For those seeking trustworthy servo stabilizer suppliers in Dubai, Abu Dhabi, Ras Al Khaimah, Muscat, or Sharjah, look no further than Benoit Technologies LLC. Being one of the leading UPS Suppliers in the region, we can provide you with high-quality servo stabilizers.

Being one of the leading oil-cooled servo stabilizers suppliers in UAE, stabilizer suppliers in Dubai, stabiliser suppliers in Abu Dhabi, stabilizer suppliers in Oman and stabilizer suppliers in Sharjah, we have been putting efforts to reach the tremendous power needs in divergent sectors. 

Don’t let voltage fluctuations damage your appliances or equipment. Contact Benoit Technologies LLC, your trusted servo stabilizer supplier in the UAE, for quality stabilizers that ensure constant power supply and protect your devices.

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