Repair of old AVR (Automatic Voltage Regulator) PCB.
Repair of old AVR (Automatic Voltage Regulator) PCB.
A look at an old AVR (Automatic Voltage Regulator) PCB that I was asked if I could fix. these devices are used in generators to regulate the output voltage, which they do by varying the DC excitation of the rotating (rotor) central core of a generator. A generator works by spinning a polarised magnetic field inside an external (stator) group of coils to induce current in them as an alternating AC waveform. By varying the magnetic field of the internal rotor by applying DC current via slip rings, you can adjust the voltage generated.
In this case the AVR (Automatic Voltage Regulator) is powered by the output voltage and also uses it to monitor voltage and frequency. It doesn’t regulate the frequency, since that is done by the device rotating the generator, but it can detect if it’s dropping too low and stop applying excitation for protection against high current flow. It monitors the voltage and compares it to a set value to determine if DC excitation of the rotor is required, and if it is then this unit uses a thyristor to switch the power to the rotors excitation coil on one half of the output waveform.
The operation of these generators generally requires a residual magnetic field in the rotor to even start producing electricity, so if a generator has not been used in a long time and that field has diminished too low to induce enough current in the output (stator) windings to provide its own excitation current, then it is sometimes necessary to disconnect the excitation windings and apply a DC current briefly (often from a starter battery) with the correct polarity to put in a base magnetic field to get the system running again. This is called flashing.
This video also shows how some fairly innocent passive components can fail as opposed to the more common active components. In this case it was a resistor that was being used well within its rating, but failed in a manner that left no obvious sign of the damage you normally see with less passive resistor failure.
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Repair of old AVR (Automatic Voltage Regulator) PCB.
Repair of old AVR (Automatic Voltage Regulator) PCB.
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Hey Clive, i really enjoy your video's! Ive got a question though, i fix up small (3-10kw) generators quite often and am wondering if you have a suggestion for any universal aftermarket avrs that would hopefully be more reliable than the original chinese crecent shaped ones.
any one can give me the circuit to make this AVR , thanks
The second trimpot you described, were you looking for the word 'damping'? 🙂
please bro whats the similar chips that i can put to replace that motorola MC 14584BCP FZR 9621 ?
CD40106 ? CD40106BE ? 40106 DIP-14 ?
Good evening sir,i'm from indonesia ..can you review how to install AVR generator…?
I haavrve an stamford mx321, the generator output voltage is not stable the output line voltage ranges from 381to 410 volts l changed the stability trimmer and the volt trimmer in the avr and the problem remains,when I connected a new avr it works properly ,is there any repairs could be done to the old avr ???
Click Bait, These are not all big clive just a random bunch of vids pertaining to similar crap
I love those old and well designed circuits, thanks for showing it
can u explain me how magnetic field generate in alternator without permanent magnet plzzzz explain me …
Can you supply board schematic? Thanks in advance.
I wonder what might happen if you apply three phases to a standard motor that inky uses two (well, one) phase, would it try and pull more to one side, 1,2+3 or 1+2,3 or 1+3,2… Would it not work, or be slow to start, or fast to reach top speed… Weirdness
Hi I have a Dunlite generator 3 kva and its gotta be about 15 to 20 years old judging by the factory yellow faded paint on every component. Problem is its putting out 335 volts at 49 -50 hertz and when I drop the rpm i can get between 240 to 250 volts but at around 10 -15 hertz! My question is should it have an avr as this looks ancient and btw there is a two screw terminal block with two brass or copper large flathead screws (i thought they were adjustable screws unless its for dc charging. I have worked with electronic boards,lawnmower repair,auto repair etc? Any reply appreciated as too why I have overvoltage problem? Great and informative vid and im about to strip it down to repair it ! Technical tips would be awesome? Thanks again from Australia 😊
And that reminds me, we need to dig out that Stamford C20B of 1978 vintage, and see if it still works! Honestly and truly, we have one on the farm – We also have a 1978 Perkins 4-154 engine to drive it, if we ever get round to marrying the two together.
It would be great to get a teardown of a modern honda/clone AVR with feedback winding/trim pot etc.
hola, tiene el circuito del avr para pasar?
I have a Dunlite generator with one unit output of 50 hz frequency at 300 volts. And another Dunlite generator with 50 to 90 hz at 4 volts even though I plugged a fan ito it? Any reply appreciated thanks?
Resistor Fails are not that uncommon these days. It's as if they don't expect the product to last more then a year or two any more. Zero Thoughts of them ever being repaired. Gone are the days when a actual Schematic is tucked away in the back of the product some place.
https://youtu.be/DoNea72ukEI what is avr and working principle
High, I have a 3 Phase 400V 11.5 KVA alternator with slip rings. Exciting field resistance is 8 Ohms. Can you help me to seize a proper AVR, what would be the current requirement?
Nice sir give me some idea about generator
Hello Friend
I have a problem on my AVR MS1 / B card, burned the ZD1 and I do not have the reference, Could you help me and tell what the reference? thanks, greetings