#generator avr

[leddypowersystemsinc]

A faulty AVR can cause all sorts of problems in a generator. So, make sure yours is in good working order. If there is a problem with your generator's AVR, get it replaced right away.

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[leddypowersystemsinc]

How to Choose the Right AVR for Your Generator?

Is your generator's power output fluctuating at an unusual rate (>20%)? The cause could be a faulty AVR. Don’t know what an AVR is? Never mind… In this blog post, we will discuss everything you need to know about this component. As you read through this blog post, you will come to know;

  What’s an AVR?

  What’s the use of AVR in a generator?

  What are the causes & signs of AVR malfunction in generators? &,

  What factors you should consider to choose the right AVR for your generator?

So, let’s get started…

AVR: What Is It & What Purpose Does It Serve?

AVR or Automatic Voltage Regulator is an important part of the excitation system of a generator. The sole purpose of this device is to ensure that the voltage output of the generator remains constant. At the most basic level, there are four different types of AVR namely- servo (linear/rotary), magnetic induction, stationary type, and solid state.

By maintaining the voltage output of the generator at a fixed rate, the AVR ensures that electrical accessories connected to the generator are functioning smoothly and efficiently. If for some reason the AVR malfunctions, the overall functionality of the generator as well as the electrical equipment connected to it will be negatively impacted.

So, what can cause a generator's AVR to malfunction, and is there any way to tell if a generator's AVR is malfunctioning? Read on to find out…

Causes & Signs of AVR Failure in a Generator

AVR failure in a generator has all sorts of causes such as excessive engine speed, overloading, an electric power surge, an electric short circuit, and aging. The functionality of your generator will be adversely impacted if you do nothing about a malfunctioning AVR. Fortunately, there are signs you can watch for if you suspect an AVR problem in your generator such as;

Sign #1- Premature failure of electric equipment

Since the automatic voltage regulator maintains the generator’s power output at a set value; if it goes bad, an abnormal power surge may happen. This power surge can damage various electrical equipment connected to the generator.

Sign #2- Unsteady voltage output

Another recognizable sign of AVR malfunction in a generator is unsteady voltage output. After all, it is the AVR that ensures that the power output of the generator remains constant. So, if you find that the power output of your generator is fluctuating, get its AVR tested.

Sign #3- Odd instrument cluster behavior

Another notable symptom of an AVR malfunction in a generator is strange instrument cluster behavior. After all, it is the AVR that meets the power requirement of the instrument cluster.

Now that we know what an AVR is, its purpose, and the causes and signs of its failure, let's discuss some of the factors you should keep in mind when choosing an AVR for your generator.

Looking For an AVR for Your Generator? Factors to Consider

If your generator's AVR goes bad and you are looking for a new one, you should pay attention to the following features.

#1- Right impedance

Make sure the AVR you're about to buy has low impedance. For those who don't know, impedance is the effective resistance of an electric circuit to alternating current. AVR with low impedance is capable of preventing harmonic distortion, voltage fluctuation, etc…

#2- How compatible is it with the load

Choose the AVR that you think will best suit your load requirement. Picking up the AVR that’s not compatible with the load requirement won’t be able to handle high starting currents. As a result, you may encounter voltage instability and other problems.

#3- Voltage regulation

Make sure the AVR you are going to pick is capable of maintaining optimal output voltage. Because if you choose the wrong one, it will not be able to maintain voltage equivalence between the generator and the load. And, that would be a cause of headache… With the right type of AVR, you will be able to maintain your generator's voltage regulation to an accuracy of ±1%.

In Conclusion

AVR or Automatic Voltage Regulator is an important part of a generator’s excitation system. It essentially ensures that the voltage output of the generator remains constant. If your generator's voltage regulator goes bad, you will face a variety of problems. So, if you suspect a problem with your AVR, get it tested and install a new one if necessary. But you should be very careful while choosing an AVR for your generator.

[starlightgenerator]

What should we do after generator AVR damaged?

Automatic voltage transformer regulator (AVR) is a sealed electronic device, which can control the magnetic field of the exciter and adjust the rectifier output power of the exciter armature, so as to control the magnetic field current of the main machine and stabilize the output voltage of the brushless generator. It has low frequency and no input signal protection device.

In addition, parallel compensation function is provided to meet the customer's demand for expanded capacity. Therefore, it is very important to maintain the voltage regulator (AVR).

What Cause Generator AVR Damage?

1.AVR circuit is composed of rectifier main circuit, voltage detection circuit and comparison control circuit. Excluding the possibility of damage caused by the quality of the original electrical components, in the whole AVR circuit, the working frequency of the main circuit and the comparison control circuit changes most frequently; the rectifier bridge of the main circuit and the transistor in the comparison circuit change more frequently, The damage ratio of AVR is more than 90%.

2.In view of the fact that the AVR on the imported generator belongs to non disassembly and repair parts, if it is damaged, it needs to be replaced. Therefore, we mainly analyze the causes of AVR damage on diesel generator. It is most important to avoid AVR damage as far as possible. As long as it is used properly, the service life of AVR can be improved. The more stable the generator voltage is, the smaller the variation frequency in AVR is; the smaller the switching action of transistor in comparison circuit is, The lower the probability of AVR damage.

3.The output load is relatively stable. The smaller the variable frequency in AVR is, the smaller the switching action of transistors in the comparison circuit is, the smaller the probability of AVR damage is; the more stable the speed of diesel engine is, the smaller the oscillation impact of changing current on AVR; frequent "traveling block" and overload, and the large difference of three-phase load are the main reasons for AVR damage; the generator set with E, F, C fuel system is selected, the use of AVR will be more reliable due to the small frequency variation.

What should we do after generator AVR damaged?

Although AVR of generator belongs to non vulnerable parts, it causes abnormal damage due to various reasons. Under the condition that all parts from the engine to the generator are in good condition and the AVR can not generate electricity and is in a hurry to use electricity, we can adopt temporary emergency measures to solve the problem of urgent need of electricity.  

1.Cancel AVR plate, only use F1 and F2 as temporary excitation input.

2.With the help of the battery of the generator, an excitation switch and a 5W, 5K ohm rheostat are installed. When the engine reaches the rated speed, the switch is turned on, the voltage is established, and the rheostat is adjusted to set the voltage at about 420v. If there is a voltage regulator regulator regulator on the control panel of the generator, it is temporarily used to stabilize the voltage by changing the wiring.

3.Not all the above methods can be used for power supply under all conditions. The following conditions must be met in order to meet the requirements: A. load ≤ 70%; B. load ≤ 20%.

4.In this method, we should pay attention to whether the charging performance of the charger is good. If the charger can not be charged, add a 24 V transformer with a voltage of more than 20 A, and then use it in parallel with the battery, otherwise the battery will run out of power quickly.    

We are a manufacturer of diesel generator set in China, we have Cummins, Volvo, Perkins, Deutz, Shangchai, Yuchai, Weichai, Ricardo etc. Power range is from 20kw to 2500kw, if you have purchase plan, welcome to contact us by email [email protected].

[dieselgeneratortech6]

Reason and solution of AVR damage

Automatic voltage regulator(AVR) is a sealed electric device, which adjusts the rectifier output power of exciter armature by controlling low power exciter magnetic field, to control the magnetic field current of the main engine and stabilize the output voltage of the brushless generator, having protection device with low frequency and no input signal. In addition, parallel compensation function is provided to meet the customer's demand for expanded capacity. Therefore, it is very important to maintain the voltage regulator (AVR).

So, what cause AVR of generator set broken? Today Starlight Power generator manufacturer answers for you.

1. AVR circuit is composed of rectifier main circuit, voltage detection circuit and comparison control circuit. Excluding the possibility of damage caused by the quality of the original electrical components, in the whole AVR circuit, the working frequency of the main circuit and the comparison control circuit changes most frequently; the rectifier bridge of the main circuit and the transistor in the comparison circuit change more frequently, The damage ratio of AVR is more than 90%.

2. In view of the fact that the AVR on the imported generator belongs to non disassembly and repair parts, if it is damaged, it needs to be replaced. Therefore, we mainly analyze the causes of AVR damage on diesel generator. It is most important to avoid AVR damage as far as possible. As long as it is used properly, the service life of AVR can be improved. The more stable the generator voltage is, the smaller the variation frequency in AVR is; the smaller the switching action of transistor in comparison circuit is, The lower the probability of AVR damage.

3. The output load is relatively stable. The smaller the variable frequency in AVR is, the smaller the switching action of transistors in the comparison circuit is, the smaller the probability of AVR damage is; the more stable the speed of diesel engine is, the smaller the oscillation impact of changing current on AVR; frequent "traveling block" and overload, and the large difference of three-phase load are the main reasons for AVR damage; the generator set with E, F, C fuel system is selected, The use of AVR will be more reliable due to the small frequency variation.

We are a manufacturer of diesel generator set in China, if you have plan to purchase diesel generators, welcome to contact us by email [email protected]. We will guide you to choose the most suitable genset with good quality and competitive price.

[dieselgeneratortech6]

Introduction of Leroy-Somer Alternator AVR R450

3.2.1.4 Excitation Limitation

The limitation threshold must be adjustable between 1 and 5.5 A. The genset breaker must be open during the short circuit. If the genset is restarted in short circuit, there is a excitation build up during 10s again at the maximum value.

Operation between 3 and 6 In when short-circuited:

The excitation current ceiling during a short-circuit equals 2.9 times the fixed threshold when setting the permitted excitation ceiling in continuous operation.

When the threshold is exceeded for a period = 10 s the current is reduced to a value between 0.5 and 0.7 A (shutdown).

In all operating conditions the maximum excitation current must be limited to 9 A ± 0.5 A.

Overrun indications:

One green LED:

- Lights up when the excitation current is below the continuous operation threshold It signals the AVR normal operation.

- Turns off when the excitation current ceiling used to obtain short-circuit operation is reached and when the excitation current is reduced to the shutdown value.

- Flashes when the over excitation counter is decrementing.

NB: After an obvious short-circuit, the voltage is limited to 70% of the rated voltage. This avoids overvoltages on machines whose no-load excitation current is below the “lower current” threshold (only in AREP).

One red LED:

- Lights up simultaneously with the green led when the continuous operation threshold is reached for more than 90 s and the excitation current is reduced to the continuous operation threshold. It is used to set the excitation current ceiling

- Turns off when the excitation current is less than the setting value (< 110% In)

- Flashes when the excitation current is above the continuous operation threshold during less than 90 s.

Green LED stays on,

- flashes when the excitation current has reached the ceiling in < 10s with PMG excitation.

- ftays on if Iexc = I Shutdown.

WARNING: If the overload protection is activated, a voltage drop possibly exceeding 10% of the reference voltage will be observed.

The AVR does not provide undervoltage protection. The customer will need to make sure that their installation is correctly protected against undervoltages.

During load shedding, an overvoltage is observed, which will disappear in a few seconds.

3.2.2 - Rotating switch selection: LAM and U/F

- Pos 0: Change in the voltage according to the U/F ratio, knee-point position at 48 Hz.

- Pos 1: Change in the voltage according to the 2U/F, knee-point position at 48 Hz.

- Pos 2: Change in the voltage according to the self auto-adaptating LAM combined with 2U/F, knee-point position at 48 Hz.

- Pos 3: Change in the voltage according to the U/F ratio, knee-point position at 58 Hz

- Pos 4: Change in the voltage according to the 2U/F, knee-point position at 58 Hz.

- Pos 5: Change in the voltage according to the self auto-adaptating LAM combined with 2U/F, knee-point position at 58 Hz.

- Pos 6: Change in the voltage according to the U/F ratio, knee-point position at 65 Hz (Tractelec application and variable speed above 1800 rpm).

- Pos 7: Special (not used).

- Pos 8: Change in the voltage according to the U/F ratio, knee-point position at 48 Hz or 58 Hz according to selection of the frequency by an external contact.

- Pos 9: Change in the voltage according to LAM 1, knee-point position at 48 Hz or 58 Hz according to selection of the frequency by an external contact

WARNING: For Pavers and hydraulic applications, select positions 0 (50 Hz) or 3 (60 Hz).

3.2.3 - Rotating switch: excitation type and time response

0: AREP excitation and normal time response.

3: AREP excitation and fast time response.

1: PMG excitation and normal time response.

2: PMG excitation and fast time response.

For SHUNT applications, AREP excitation must be selected.

3.2.4 - Rotating switch: voltage sensing

0: Single phase sensing

- LSA46 / 47 series.

3: Single phase sensing

- LSA49 / 50 series.

1: Three-phase sensing with optional module R731

- LSA46 / 47 series.

2: Three-phase sensing with optional module R731

- LSA49 / 50 series.

3.3 - U/F and LAM function

3.3.1 - Frequency variation compared with voltage (without LAM)

3.3.2 - LAM (Load Acceptance Module) characteristics

3.3.2.1 - Voltage drop

The LAM system is integrated in the AVR. As standard it is active.

Role of the LAM:

On application of a load, the genset rotation speed decreases. When it falls below the preset frequency threshold, the LAM causes the voltage to drop proportionately to the frequency (LAM1) or to the active power (LAM2) depending the the rotating switch position. This reduces the active load scale applied until the speed returns to its rated value.

Hence the LAM can be used either to reduce the speed variation (frequency) and its duration for a given applied load, or to increase the applied load possible for one speed variation (turbo-charged engine).

To avoid voltage oscillations, the trip threshold for the LAM function should be set approximately 2 Hz below the rated frequency.

3.3.2.2 - Soft voltage recovery function

During load impacts, the function helps the genset to return to its rated speed faster with a gradual increase in voltage according to the principle:

- If the speed drops between 46 and 50 Hz (in 50Hz operation), the rated voltage is recovered by following a fast gradient.

- If the speed drops below 46 Hz, since the engine needs more help, the voltage follows a slow gradient as it returns to the reference value.

3.4 - Typical effects of the LAM with a diesel engine with or without a LAM (U/F only)

3.4.1 – Voltage

3.4.2 – Frequency

3.4.3 – Power

3.5 - AVR options

- Current transformer for parallel operation of....../1 A or 5 A according to the potentiometer P4 position.

- Voltage transformer (adaptation)

- Remote voltage adjustment potentiometer.

For a range of variation:

± 5% : 470 Ω

± 10% : 1 kΩ

the power of the potentiometer can be 0.5 W, 2 W or 3 W.

The potentiometer input must be isolated. Do not connect it to the ground.

- R731 module: 3-phase voltage sensing 200 to 500 V, compatible with parallel operation in balanced installations.

- R734 module: 3-phase current and voltage sensing for parallel operation on unbalanced installations (unbalance > 15%).

- R726 module: regulation system changed to “4 - function” (see the maintenance manual and connection diagram).

• PF regulation (2F) .

• Equalization of voltages before paralleling (3 F).

• Possibility of coupling to the mains of alternators already running in parallel (4F).

- R729 module: same as R726 with additional functions.

• Detection of a diode fault.

• 4-20 mA input.

• Possibility of kVAR regulation.

- Voltage control: with an isolated D.C. current source applied to the terminals used for the external potentiometer:

• Internal impedance 1.5 kΩ.

• A variation of ± 0.5 V corresponds to a voltage adjustment of ± 10%.