AUTOMATIC VOLTAGE REGULATOR (AVR)

What is automatic voltage regulator (AVR) and why do diesel generators need to be equipped with one?

Diesel generator is a very important complex machine, especially when it is used in the work site or buildings. They are essential tools in case of emergency, and provide you with continuous and stable power security in the absence of power grid. However, people still don’t know much about diesel generators, especially the importance of automatic voltage regulators.

AVR is a solid-state electronic device, which is used for diesel generator to automatically maintain the voltage at the output end of the generator at a predetermined level. The voltage level in the generator may fluctuate, especially when the load or operating temperature fluctuates, and the AVR as part of the alternator excitation system is used to neutralize the output voltage. It stabilizes the output of the generator, often with inconsistent loads, but it can also separate the reactive loads between multiple generators operating in parallel (called voltage sag), and can assist the generator in case of overload.

Although it is small,  its appearance is similar to the motherboard of a computer – automated voltage regulator can control the output by comparing the voltage emitted by the terminals of the electronic induction generator with a predetermined voltage level. Then it sends an error signal to the exciter stator to adjust the excitation current (by increasing or decreasing the current), and the exciter stator adjusts the terminal to a higher or lower flow.

In short, the automatic voltage regulators will constantly monitor and adjust the voltage of the generator or used generator to maintain a fixed voltage level.

Why is AVR important for generators?

Diesel generators that are not equipped with automatic voltage regulator and are considered unregulated usually have problems meeting the power requirements of equipment or equipment connected to the generator. If you work closely with generators, you will know that a generator may need to supply power to a variety of equipment or machines. Many non regulated generators without AVR cannot adjust the voltage output by themselves. Therefore, if more equipment and machines need power – the more voltage output they need – the terminal voltage will gradually decrease, which means that the connected equipment will not have enough power voltage to fully supply power.

The use of automatic voltage regulators is crucial for generators, because if the voltage output is constantly changing or decreasing, rather than maintaining at a fixed predetermined level, it will affect the performance of generators and equipment connected to them.

The generator automatic voltage regulator also helps to maintain the output terminal at a safe voltage level and can provide surge protection. Without AVR, the generator may output a terminal voltage that is too high for the equipment or machine it supplies, which may overload the equipment. This will not only damage the connected equipment, but also may be very dangerous, resulting in electrical fire or electric shock. AVR can help the generator adjust the voltage level during overload to prevent electrical short circuit.

The use of automatic voltage regulators can improve the efficiency and prolong the service life of the generator, including the equipment connected to the generator. It specially monitors the voltage output to ensure that the voltage value is consistent. Without AVR, the voltage level may fluctuate violently and damage the machine.

Automatic voltage regulator for generator is an important device with many advantages because of its small size but powerful function. AVR is usually combined with other power quality capabilities, such as surge suppression and prevention, short circuit prevention, voltage balance, line noise reduction and harmonic filtering.

Automatic voltage regulator is a complex device. Its function is far beyond what we can see. It consists of many precision components, including contact voltage regulator, transistor regulator and computer-controlled regulator. All these parts together make AVR an important configuration of generator.

The purpose of automatic voltage regulator is to automatically adjust the output voltage of generator.

AVR voltage regulator of diesel generator currently used

(The Brands mentioned here are for reference purpose only, our parts can exactly replace the original ones.)

AVR Brands: Stamford, Lerory Somer, Marathon, Mecc Alte, Marelli, LINZ, Kutai, Basler, Caterpillar, Kato, and etc. 

Stamford AVR: AS440, AS480, SX440, SX460, MX341, MX321, AS540, DM110, MA330, MX342, SX421

Leroy Somer AVR: R220, R230, R250, R438, R448, R449, R450, R450M, R450T, D510, D510C, R120, R129, R130, R150, R181, R211, R212, R221, R222, R231, R238, R241, R251, R443, R452, R610, R630, R713, R723, R725A, R726, R729, R731

Marathon AVR: SE350, DVR2000E, DVR2000EC, DVR2000E+, PM100A, PM300E

Mecc Alte AVR: SR7-2G, UVR6, DSR, DER1, DER1/A, DER2, ASR

Marelli AVR: M16FA655A, M40FA640A/A, M16FA667A, M40FA620A, M40FA621A, M40FA644A, M50FA400A, M63FA310A, M71FA300, M71FA310, M71FA320

LINZ AVR: HVR-11

Kutai AVR: EA04C, EA05A, EA05AF, EA08A, EA15A-2, EA16A (50HZ, 400HZ), EA350, EA440, EA440-T, EP200, EA15A3H, EA63-7, EA42-7, EA63-5, EA64-5

Basler AVR: AVC63-4, AVC63-4A, AVC63-7, AVC63-7F, AVC63-12A1, AVC63-12A2, AVC63-12B1, AVC63-12B2

Caterpillar AVR: VR3, VR6

Kato AVR: K65-12B

Universal AVR: AVR-8A, AVR-10A, AVR-10B, AVR-15A, AVR-15B, AVR-20A / GAVR-8A, GAVR-10A, GAVR-10B, GAVR-15A, GAVR-15B, GAVR-20A, GAVR-25A

We have an evaluation of some models

SX460 : Cheap Alternator AVR, high quality but very reasonable price!

AS440: AS440 Stamford Alternator AVR is the new model that replacing SX440 Geneartor AVR. original SX440 Genset Voltage Regulator had been discontinued, but we still have SX440 in stock. Stamford AS440 AVR is a half wave phase controlled thyristor type AVR and forms part of the excitation system for a brush-less generator. The design employs Surface Mount Technology (SMT) for high integration of features in a small footprint AVR.

AS480: The Stamford AS480 AVR for Alternator is linked with the main stator windings and the exciter field windings to provide closed loop control of the output voltage with load regulation of +/- 1.0%. The AVR voltage sensing terminals continuously sample the output windings for voltage control purposes. In response to this sample voltage, the AVR controls the power fed to the exciter field, and hence the main field, to maintain the machine output voltage within the specified limits, compensating for load, speed, temperature and power factor of the generator.

SX440: original SX440 Voltage Regulator for alternator had been discontinued, but we still have SX440 in stock. INPUT : Voltage 190-264V ac, Frequency 50-60 Hz nominal, Phase 1, Wire 2. OUTPUT: Voltage max 90V dc at 207V ac input, Current continuous 4A dc, Intermittent 6A for 10 secs, Resistance 15 ohms minimum

MX341: Stamford MX341 AVR is a two phase sensed Automatic Voltage Regulator and forms part of the excitation system for a brush-less generator. Excitation power is derived from a three-phase permanent magnet generator (PMG), to isolate the AVR control circuits from the effects of nonlinear loads and to reduce radio frequency interference on the generator terminals. Sustained generator short circuit current is another feature of the PMG system. 

MX321: The MX321 AVR for Stamford Generator senses the voltage in the main generator winding and controls the excitation to maintain the generator output voltage within the specified limits, compensating for load, speed, temperature and power factor of the generator.

 

R250 : Most popular AVR for diesel alternator, high quality but very reasonable price! 

R230 : original R230 had been discontinued and replaced by R250 AVR, but we still have R230 (Replacement) in stock. 

R438 : Leroy Somer R438 diesel alternator AVR is an analog AVR. It is designed for alternators with a AREP or PMG excitation. Leroy Somer R438 AVR controls the excitation current in order to maintain the output voltage of the alternator. 

R448 : original R448 and R449 had been discontinued and replaced by R450 AVR, but we still have R448 (Replacement) in stock. 

R449 : original R448 and R449 had been discontinued and replaced by R450 AVR, but we still have R449 (Replacement) in stock. 

R450 : R450 AVR for Leroy Somer Generator is an analog A.V.R.. It is designed for alternators with a SHUNT, AREP or PMG excitation . R450 Leroy Somer Voltage Regulator controls the excitation current in order to maintain the output voltage of the alternator. Leroy Somer R450 is performant in terms of voltage regulation, simple to set, to use and is reliable. 

R450M : The Leory Somer R450M AVR has all the same functions with R450, but R450M have special connectors, you can see the details of connectors from the photos in our website. 

 

SE350 : Most popular AVR module, high quality but very reasonable price! 

DVR2000E+ : The Marathon DVR2000E+ genset voltage regulator is a new model that can replace DVR2000E AVR. DVR2000E+ has REMOTE CONTROL function, but DVR2000E has not. 

DVR2000E : The Marathon DVR2000E AVR was discontinued, there are 3 options for DVR2000E AVR:

         Option 1: Use our replacement model for DVR2000E (All the same function, 1 year warranty, best choice.)

         Option 2: Use original Marathon AVR DVR2000E+ (More functions but more expensive too)

         Option 3: Use original Basler AVR BE2000E (same function but more expensive)

 

SR7-2G: Most popular AVR module, high quality but very reasonable price! Meccalte SR7 AVR a negative feedback system, in which the constantly maintained variable is the alternator voltage output. This voltage, after adequate conditioning, is compared with a signal that is stabilised in voltage, temperature and age. The result is an error signal which, when opportunely amplified and compensated, produces a control level that enters an impulse width modulator. 

UVR6: The Mecc Alte UVR6voltage regulator is an advanced design electronic regulator that ensures excellent performance of the Alternators while they are running and during starting. The regulator is equipped with a complete protection system against operation conditions that could be dangerous for the machine.  

SR7-1, SR7/1 : The Mecc Alte SR7-1, SR7/1 Diesel Alternator AVR was discontinued and replaced by SR7-2G now. 

DSR: The Mecc Alte Generator AVR DSR is a voltage regulator for synchronous alternators, designed for stand alone working and calibration; to maximize performance, the regulator should be understood as part of a system made up of at least three components: the DSR (control unit), a communications module (USB2DxR, for example) and a supervision unit.

DER / DER1 / DER 1A :The DER1 is a voltage regulator for synchronous alternators, designed for stand alone working and calibration; to maximize performances, the regulator should be intended as part of a system made up of at least three components: the DER1 (control unit), a communications module (USB2DxR, for example) and a supervision unit. 

The ASR AVR for Mecc Alte generator Voltage Regulator is a closed loop automatic voltage regulator system, that controls and keeps constant the alternator output voltage. The output voltage of the alternator is monitored and confronted with a reference signal: the difference between the two is used to control the conduction state of an SCR.

The Mecc Alte DER2 AVR is a voltage regulator for synchronous alternators, designed for stand alone working and calibration; the connectors for connection to and from the power generator and to the supervision unit are located on the DER2 regulator.

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