How to check the voltage regulator of a Bosch alternator

How to choose an analogue AVR of a three-phase alternator

In online stores you can buy an AVR for any type of three-phase generator for just a few dollars. The main criterion for choosing an analogue of AVR is the real power of a gasoline generator or a diesel power plant. The easiest way to pick up the automatic voltage regulator block for the Chinese power plants, including those sold under the Russian-speaking brands. all of them are made from virtually identical units, so there is a 90% chance that the ATS units will fit together without any problems. Read more details about Chinese parts here

The second criterion is the voltage and capacity of the large capacitor on the AVR unit. Take the defective AVR and look carefully at the capacitor rating. Despite the fact that AVR unit is usually covered with black compound, capacity and voltage of the protruding capacitor are easily readable.

Attention! For Chinese and Asian generators, the voltage and capacitor capacity may become a key factor in selecting the analogue of AVR. The fact is that in the pursuit of the buyer, the manufacturers often deceive, overstating the passport data, and actually on the 7kW Chinese generator will be AVR 5kW. Usually the AVR up to 5 kW has 330-470 uF capacitor and the AVR over 7 kW has 680 uF capacitor. At the same time on the AVR over 5kW there is a blue potentiometer, which regulates the output voltage.

Causes and possible consequences of malfunction

Malfunctioning of the alternator is possible due to the following reasons:

  • Faulty voltage regulator (“pill”, “chocolate” in motorists’ slang);
  • Wear (destruction) of the brushes;
  • short circuit in the excitation winding (rotor);
  • diodes (located in the horseshoe) breakdown;
  • Wear of bearings and bushings.

Faulty voltage regulator usually leads to the absence of charging the battery. If this occurs, the “battery” icon on the dashboard will light up. The engine continues to run until the battery is discharged to about 8 to 9 volts.

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During daylight hours the battery charge may be sufficient for 30.50 km if the battery is fully charged at the time of the fault.

At breakdown of output stages of voltage regulator may cause defect, connected with increase of output voltage of alternator up to 17. 20 Volt. In this case the battery is overcharged. Overcharging results in boiling of electrolyte. If traces of corrosion appear under the hood in the area of the battery, it is necessary to check the alternator.

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Breakdown of the diode bridge may occur in case of accidental reverse polarity of the battery (setting the terminals in wrong polarity). Diodes are usually broken in pairs in one arm. Defective diode has resistance close to zero. The alternator stator winding in such a case is working in the short circuit mode, strongly heats up.

After several minutes of engine operation the windings overheat, under the hood of the vehicle appears the smell of burnt electric wiring. In order to avoid ignition it is necessary to switch off engine, check alternator.

Wear of brushes leads to gradual failure of alternator. At first the charge indicator light on the dashboard starts blinking while driving, then it begins to glow constantly. In many models of alternator brushes are changed together with voltage regulator.

How to Test an Alternator ( Testing the Voltage Regulator, Diode rectifier and Stator)

Short-circuiting the alternator windings can lead to a significant change in output parameters, overheating the device.

How to check the regulator relay. With your own hands, using a multimeter. Very simple

Problems of “undercharging”, as in principle and “overcharging” the battery, can be caused by many reasons, but the first and most common in many cars (our VAZ is no exception), as well as on many motorcycles, is the output of the alternator regulator relay out of operation. This device, in spite of its compactness, will save your battery and make its life much longer. However, if it fails, it can simply kill the battery in a matter of weeks, so if you see white streaks, and also, the engine does not start after night, even “does not twist” the starter. it is time to check the relay regulator of your car, but here is how to do it with your own hands, and you today will tell in detail.

A voltage regulator is a device that regulates the current from a car’s alternator, preventing the battery from overcharging, keeping it from overcharging, destructive to the battery. Thus, this device greatly prolongs the life of the battery.

In fact, this is just a voltage regulator that does not allow the voltage from the generator to exceed the threshold of 14.5 volts, it is a very accurate device and mandatory for all types of cars. However, it can be distinguished into two types.

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The main signs of malfunction

The very first sign of malfunction is the lack of glow of the control light (indicator) on the dashboard when you turn on the ignition.

In older cars, where the circuit of the battery charge is similar to that shown in the first figure, it is still too early for motorists to panic. It may just be a burned out bulb or broken contact, and these cases are quite common. Car owners remove the alternator, take it for testing, and in vain.

The second sign. the indicator “battery” does not go out after starting the engine. This already indicates a disturbance in the charging process and a possible malfunction of the alternator.

Another sign of malfunction. the brightness of low beam. high beam depends on engine speed. By the way, it is recommended to do this check regularly. To do this, stop in the dark in an unoccupied place in front of a building and on neutral to turn off the main light. A change in brightness indicates possible problems with the charging system.

The smell of burning winding in the cabin is also a sign of generator failure, but you may not feel it.

check, voltage, regulator, alternator

Check of combined voltage regulator

If the brush assembly will be combined with a relay, you will need to remove the alternator to check. To begin with it is necessary to check the combined scheme of a relay-regulator, which is used today on many foreign cars and even domestic cars.

To do this you need to remove and disassemble the alternator, t. к. The assembly we need is attached to the shaft of the alternator, on which the brushes run. Look for a “window” on the alternator for the brushes, unscrew the mounting bolt, take out the brush unit and clean it. It’s usually in graphite dust.

Now we need to build a special circuit using a power supply with adjustable load. We also need a battery, because the power supply or charger doesn’t work without one. So, we connect the charger to the battery and in parallel with the voltage regulator, and connect a 12 volt light bulb to the voltage regulator.

With this connection, the light will be on. this is normal, because the charger has to be switched on. к. The brush node is a conductor, and at rest the voltage here is 12.7 В. Now we need to increase the voltage of the charger to 14.5 В. The lamp should go out when it reaches this value. After all, 14.5 V is the “cut off” of the voltage rise. And if the light goes out, it means that the voltage regulator has worked and it is in principle functional.

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Otherwise, if the voltage reaches 15-16V, and the light is on, it means that the relay does not give cutoff. In this case, you need to replace it with a new one.

Now you know how to check the voltage regulator with a multimeter, and you can do it yourself.

A relay is a separate device (as opposed to integrated circuits) used to control high power signals with low power signals. The relay separates and protects the low voltage circuit from the high voltage circuit by means of an electromagnetic coil. This article will tell you how to test both the relay (solid state) and the coil.

What is it, where is it located, how does it work?

This part of the car is responsible for maintaining the onboard voltage within certain limits. Regulator controls ambient temperature, rotor speed, electrical load level and other parameters. It also protects the generator’s sensitive components from overloads, and is responsible for activating the field winding and other systems.

The product is directly in the alternator. Regardless of the machine model, the principle of operation of the regulator is the same. when the voltage increases or decreases, the component reduces or increases the excitation current to return the indicators to the desired level.

Function and purpose of the relay

Classic voltage regulator relay contains a control winding, which is connected in parallel with the battery, and normally closed working contacts through which the battery receives charging current. If the threshold voltage is exceeded, the relay triggers, cutting off high voltage supply to the battery. The relay functions as a voltage regulator. The term used to describe it describes the function of the first series-produced automotive voltage regulators.

Why an alternator voltage regulator burns out

A voltage regulator is an electronic device installed on automobile alternators to stabilize the input voltage to the battery. It should be between 13.2 and 14.5 volts. Both upward and downward deviations are unacceptable. This would already be a malfunction of the generator. In most cases, it is the voltage regulator that is responsible for the malfunction. This device, although small in size, is what protects the battery from premature failure.

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