AVR GENERATOR BOARD KEEPS BLOWING

Hello Mally,

More details please,

a) Is it blowing out while on load or during start up?

b) Details of AVR, make, type etc?

c) Is the AVR mounting done on a vibration proof studs, and does it have proper ventilation?

d) What is the manuacturer/supplier saying about the problem?

e) Did you check the connections specially the sensing voltage connections?

f) While it is working is the voltage stable or has fluctuations?

cheers.

Hi

a) The board is blowing on start up

b) The generator is a Stamford made in China and run by a Cumins diesel engine, unfortunatly the AVR boards do not have any manufactures names on them.

c) The AVR is not mounted on vibration proof studs and is mounted inside a protective area on the side of the generator, it doesn't seem to have good ventilation.

d)I have had no luck from the munufacturers, they don't answer my emails

e)We have checked the connections and all seem to be good, the sensing voltage connections are also good.

f) When the generator is running it is very stable, and doesn't have many fluctuations at all.

Hope this helps

Mally

Please publish the name of the supplier and manufacturer so that others will not fall into the same trap of buying from such a 2nd rate company....that is very important....no service = no sales (at least as far as CR4 goes!)

Probably the company knows they have a problem, probably they do not know why, which is why they are ignoring you completely.

At least you should be getting the replacements for free as most companies guarantee longer than 2 months. If not, look around in Europe or the USA for a replacement made by a good company, even if it costs a lot more, agravation must also be given a value!!!

Thank you

Unfortunatly in Africa the market is flooded with products from China and it is sometimes very difficult to find the original supplier.

Products are sold with names of reputable first world suppliers printed on them, when in actual fact they are sometimes Grey products and one has a big problem trying to get spares for them.

Unfortunatly this doesn't solve the problem that we have at the moment.

Can you take a photo of the AVR (showing the connections clearly) and post it.

Use the Green camera which you see on the top of posting window to attach the photos.

Also hope your generator body has been properly grounded to a good earth pit.

cheers.

congrats you have the privilidge of owning a high quality knock off. the only way you are going to get anywhere with it is to let it burn up completely.then get siemens ag to ship a real unit via johannseburg distributions networks.

not to demean your situation but as has been repeatedly posted here the fakes coming out of the orient especially china are pretty good i understand the dudleys up in canada are having a real problem i'dying the csa knock offs from the real goods.

'da ber

It sounds like the capacity or voltage ratings of components in your AVR boards are not good enough.

A circuit diagram with indications of which components are failing could be of help to recieve advise on what to do?

halo mally

I have same problem as you, my AVR is stamford sx 440, my generator engine its komatsu eg 80,The generator take taiyo AVR but its broken now, taiyo not been production now, so iam change with stamford sx 440 but when iam use about 6 month and now is burns out

my opinion are, are my generator have problem so my AVR is burns out ?

cause the taiyo AVR i am change for 2 times and the stamford for frist time

please some one give mally and me solution

regards

Taufik ( opik32@yahoo.co.id )

For a 65KW Stamford alternator the AVR should be normally SX460 and has got only 4 connections made to it, 2 for sensing 230V and 2 for supply to exciter, + and - terminals.

The rated current of AVR is 4A running and max 6A for 10s.

Place an ammeter in the output circuit and measure current . If it exceeds the rated current , it can be assumed that there is a fault in the exciter.

Measure resistance of exciter winding. It must not be below 15 ohm.

Otherwise the problem lies with the AVR itself.

You must purchase a unit made in UK and try the same.

Thank you for the info

I will get somebody to check it tomorrow and will reprt back with my findings

Regards

Mally

Hello Mally

my AVR stamford made by NEWAGE AVKSEG England

this is my AVR

from the manual book the stability selection can we change from 90 to 550kw

this is the fitting diagram

hope with my info some one can give me solution

regards

taufik (opik32@yahoo.co.id)

Taufik:

Can you post an in-focus shot for the schematic of this board? As I told Mally, I think you may have boards with a design flaw but without the schematic I'm just giving likely failure possibilities.

avr not send power

Send me avr image. Ok

This is slightly out of the field of my practice, but electronics is electronics. I see two items on the board that appear to handle some power, the 'module' near the external connections and the long resistor on the right side of it. These do not appear to handle very much power but if the module is getting too hot, it could be degrading over time and failing. Heat is the enemy to components and has done in a lot of circuits. Unless the resistor is showing some signs of over heating (discoloration), it is not too likely to be the culprit here.

Voltage transients can also be a problem here, I cannot tell from the picture but there may be transient suppressors below the module. These normally have a very high resistance reading, if they have a continually dropping resistance over time, they are eating a heavy transient. They may or may not have discoloration.

The suggestion of the excitor coil possibly being bad is also a good. It is not unusual for a turn or two to short out in the winding (particularly if the quality of the wire insulation is not good). This may not significantly change the DC resistance but will increase the current load significantly upon startup. A shorted turn can double the normal current load.

Is there any visual indication of what is failing on the board when it 'blows'?

Hi Taufik

The picture of your AVR is exactly the same as mine and the wiring diagram that you have taken a picture of is exactly the same as the one that came with my AVR.

I am a hotel owner in Mozambique and don't know a lot about technical things on generators but I am learning fast, however I am trying to find a solution to my problem, I have a basic electrician on site and am trying to gather as much information as possible so that I can get him to check everything to find out where my problem is.

Can anybody tell me how I can do a simple test to check the exciter and where must we put the meters probes to check for the 15ohm rating.

Once I know that the exciter is K then I can work on the AVR as I have a spare one but this is not working at the moment

Sorry if I sound uneducated in generators, I am. Please teach me

Thanks

Mally

with regards to the damage on the board, the board is badly burned and lots of blown components, strong smell of burnt electronics as well

Mally:

You've got catastrophic failure of the board, meaning something on the front end of the circuitry is failing (overloading). The circuitry I see in the picture is all low voltage, meaning that the input voltage, in this case, 230 volts, must be reduced in order for the circuits to function.

This failure indicates that some component(s) in the power supply of this board is being overloaded regularly and then fails in a shorting mode (this does not mean zero resistance however), allowing too much voltage to reach the other components, literally frying them.

It is difficult to troubleshoot over the internet, precisely and the lack of a schematic complicates things. But it would appear that you have boards with a design flaw that needs to be addressed. Unfortunately, the manufacturer appears to be ignoring everyone so that eliminates one source of boards for you. Their lack of response probably confirms that they are having trouble with their boards.

As suggested, finding a better source, such as Great Britain or the USA may provide a more reliable board. Sorry to say, I am in the USA or I could correct the flaws for you. You might look around for an electronic design engineer there and consult him, he should be able to figure out the problem and correct the design flaw. That may be a less costly route to take. I do not see any comparatively expensive parts on the board.

You should have a general wiring diagram ,if you can photo same somebody can identify input and output connections and give you some pointers on what to check out.

Good pointer from post re 12V battery on field to test output of machine expect field current from 2 to 5 Amp. Resistance of field can be checked across the slip rings. observe the polarity of the meter to agree with the normal supply.

Current for field regulation is usually taken from a separate stator winding make sure there is no readings to any of the other windings or to ground for this winding. There are problems which could arise only when the machine is running but it will be difficult to identify these. But if you have only 2 wires in and 2 wires out then the field current is derived from the 240V output, this is not the best design for a regulator as it has to cope with a lot of voltage fluctuations which if not well regulated could lead to voltage surges this could cause the regulater to self destruct.

Finding a shorted turn or two can be the hard bit. Using a multimeter may show it as ok and it may need sufficient turn to turn voltage to initiate the short circuit current. Bear in mind most likely the current will be controlled by a switch mode device which by its very action will cause voltage spikes within the coil. AC drop tests are good for finding these types of short, but a known value is required eg series up two coils and measure the voltage dropped across each. This may not be practical if only one coil is available but is worth keeping in mind as it finds faults hidden to other methods. If only one coil is available use DC current to calculate the actual resistance. Run the coil at rated current for sufficient time to warm up the coil and measure the voltage dropped at intervals, it may need to be warm to fail. Calculate the resistance from Voltage and current. The value should rise as a function of temperature any fall in resistance, even a small one, is a fail. This testing will also reveal intermittent open circuits which may also destroy the AVR due to voltage spikes. To reduce the problem and find more data I suggest that you install a closely rated fuse in the field circuit while testing.

Assuming poor design.

The active component doing the switching will suffer heat if over current is the culprit so forced cooling can be a life saver. If no joy can be found, sometimes closer inspection by someone experienced in power electronics can help. I have lost count of the amount of dud circuits I have had to modify. For instance the slew rate of the switching device may too slow or the switching device not adequately heat sinked. The latter is much more common than manufacturers will admit, especially European designs, whose designers have no understanding of the tropics.

If it is a knockoff then the control element may be a simple series pass item which means the aforegoing is true in spades. If it is a series pass item then have a suitable well heat sinked amplifier built. In remote areas gear that can be fixed with use of components available from RS or Farnall etc is a definite bonus.

Hello Mally

my AVR cannot burns like your AVR cause iam protect with MCB 3 amp,if i have no protect i thing my AVR burns like that.

for my generator resistance range is above 20 - 25 ohm

for chek the generator you can use battre 12 vdc ,connect the battre to excitor,up rpm of you engine to standart used,and look your electrical instrument, are the volt meter and hz meter is in.

feed back please

regards

Taufik

Hi Taufik

I need to know where to put the battrey terminals on the exciter wires, are these the wires which go into X and XX on the AVR board. if so which one is positive and which is negative.

Must I connect the battrey 12vDC to these wires and leave it on or do I just put the 12vDC on for a short time and take it off quickly?

Thanks

Mally

OK I have done lots of tests,

I connected a 12vdc battrey to the exciter wires + and - and then checked the voltage reading on the six terminals on the top of the gererator. I get a reading of 20 volts on the 3 right bank of terminals and 10 volts on the 3 left side terminals.

I have tried by putting the battrey on for only 5 seconds to try and excite the generator then for 10 seconds and after this I left the battrey connected, only get the 20 volt and 10 volt readings. (Even swopped the polarity of the battrey to check that we had it right)

In desperation I have disconnected the AVR board completely and tried to excite the generator on it's own still only get the 20 volt and 10 volt readings on the gererator terminals, the voltage tests were done between each terminal and earth.

Is my gererator broken?????

Please help again

Mally

Try putting a 10 amp slow-blow fuse in series with the excitation output.If it blows, you know the fields are shorting under load. The droop adjustment could also be set too tight,and max out the output before the generator reaches full voltage, like at start up. If there is no adjustment procedure, begin with adjustment at half way point, and make small adjustments up, or down, to get the minimum amount of gain required to provide adequate service. If the present board does not work, it might be repaired if you have a competent electronic shop nearby. Where does the supply for the card derive?I would suggest a separate 220 volt supply for the card if possible.It may be getting "looped up" if not properly designed, and go into a voltage runaway condition.Example: When the generator is idle, there is no voltage into or out of the card.AS the speed builds, the voltage is still below set point, so the module maxes out the field current.This makes the generator produce maximum voltage, and before the board can recover, the voltage has gone very high, possibly high enough to kill the board.If the board survives start up, it regulates fine.This also could be related to the droop adjustment. Lots of possibilities. Very hard to judge a "pig in a poke" ( a pig in a sack).

Quest, there was a recent thread discussing the number of people that fail to post their location when they sign up to be a member. Your terminology. I would say places you in the state of Indiana, am I close? (my uncle Poke had a pig valve placed in his heart, can you imagine the one comment he heard the most?)

Thank you for all the information, I will be doing all the different tests when my electrician arrives later today and will report back on what the out comes are.

Thanks

Mally

Dear Mally,

Please do not connect 12V battery to aVR teminals unless you disconnect the AVR completely as you may damage the AVR by doing so.

Check current output of AVR by connecting a DC ammeter. You can use a multimeter for this purpose. Set multimeter on DC amp. Disconnect wire from X terminal and connect to -ve probe of multimeter. Connect +Ve probe of multimeter to the X terminal of AVR.

Start generator. Check reading on ammeter. It must not exceed 4A normally or it may take 7.5A for a maximum 10S. If these values are exceeded then you have a fault on the exciter.

Thanks for the info, I will try this in the morning

Mally

Hello mally

X is positive

XX is negative

how much ohm your excitor field ?

first check excitor resistance ( use multi tester ) if have resistance and no shot on excitor field connect the wire x to positive and xx to negative rise up the rpm engine to standard don't disconnect excitor wire ,look your instrument panel ,are voltage and hz meter up ,if up you generator is fine

feed back please

regards

taufik

OK I have tested the resitance of the exciter and I get zero resistance, I would presume that this means that my generator is not working. Unfortunatly it is New Year and every supplier is closed in Africa until the 5th of January so I can't even get a spare AVR ordered until after the 5th of January so that I can check things with a new board.

I know that it might sound crazy that we can't just get a professional to come and fix the problem, unfortunatly we are 2000km from the nearest main centre being Johannesburg, South Africa, so we have to try and fix some of the eqipment ourselves, before we pay for a technical person to fly out to us, then he has to travel 300km on bad roads before he gets to us and this whole process usaually takes about a week, so you can imagine what the costs will be.

Everyone of you has been most helpfull in trying to solve my problem and I can't thank you all for the valuable information that you have provided me with, I almost feel like a generator expert now (Ha Ha)

I think that Our best option is to order another AVR from the suppliers in South Africa after the 5th of January and if this doesn't work we will then have to buy a new generator.

I promise we will never ever buy a Cummins/Stanford unit again, our last Generator was a Massey Ferguson and lasted 10 years, maybe we need to get another Massey and be done with this problem once and for all.

Thank you everybody for all your help, If any of you ever land up in Mozambique, please contact us, and hopefully we will be in a position to repay your kindness.

Best Regards

Malcolm Warrack

Owner

Casa Barry Lodge

Tofo Beach

Inhambane

Mozambique

www.casabarry.com

If you get zero resistance it means that the exciter is most probably short circuited or windings are short.

To confirm this, connect 12 V toX and XX terminals. of exciter and run the generator.

you will smell some burning.

Also if you open the alternator cover you will notice that the winding is burnt as it will be black.

you will need to rewind the same and it will be fine.

Great I will try this, I have tried this with 12vDC and nothing burned or smelt of burning, must I try it with 12vAC, will this make a difference???

Mally

no use 12 vdc

Dear Malcolm:

Did you measure the resistance of the exciter coil disconnected from the AVR board or while it was still connected? The AVR could have been the source of the zero ohms reading. If the exciter coil did read zero, then it has, unfortunately, shorted out and will destroy another AVR board. A fuse as suggested earlier may protect the AVR from immediate damage but only covers up the faulty condition.

I fully understand your predicament, being located where you are. Very expensive no matter which way you turn.

On another point though, you initially said that a board lasts for two months before blowing. A shorted coil would usually cause immediate damage, period, the board could not last two months driving a shorted coil. If your answer to my question above is that you checked the coil, disconnected from the board, then I would have to say that you have unintentionally damaged the coil trying to test the coil with the battery somehow.

Given your initial statement on the board's repeated failure after two months, I would have to say that heat is the most likely culprit followed by a most likely under-designed circuit for your conditions. I agree with Emjay4119, that if you could provide some kind of additional air flow over the board, it could help reduce the risk of the module failing. That may be difficult if there is little room to spare inside the generator.

I sympathise with you mate. Things can get hard in Western Australia but not quite as bad as your situation. If your exciter coil is stuffed, then that is definitely a bad look, if it is not then the system can be jury rigged to operate at a constant load.

Replacing the unit given your remoteness is still going to be a challenge as many formerly reputable brands now outsource components. What is second nature to experienced people like myself can be hard to convey especially on an open forum. To complete tests by remote control using unskilled labour requires a clarity that is compromised by chatter. What may help you is to try a one on one contact with whoever you think will be the most use. CR4 allows this function.

For remote applications the most simple system is best even at the sacrifice of some performance.

If he has only 20V on alternator terminals this is not high enough to drive the AVR up to 4Amp, in any case it sounds as if the AVR is damaged.{ It should be bench tested} unfortunately the operator has limited equipment and knowledge and should use an expert technician before he causes any further damage to the machine or himself.

The stator and rotor winding needs to be checked to make sure they are within specifications whatever this might be, handing further information out on this problem even if well intended could mislead the operator who has not supplied enough information to do something wrong and or dangerous.

Cummins, Stamford and Newage are all part of the same company. If this was made in chaina then i would suspect that it is an outsourced product. Get onto your local Onan/ Cummins generator dealer for more assistance.

Mally, it sounds as if someone has replaced the fuse which is normally in the field circuit with an overrated fuse.

Taufik, you have fitted a 3A mcb? Is that AVR rated at 6A?

If your problems only occur every few months then we can more-or-less discount a wiring error. Either you have an intermittant short circuit or you are going into overload. How is the UFRO set up? If this is not set correctly then the AVR will be attempting to get full output before the gen is at 1500 (1800) RPM.

regards

Chas.

Hello all cr 4

Mally ,just for info you can use ELCB it more protect than mcb

my generator will use stamford cause my taiyo AVR not been production in japan but now i will more protect with elcb cause there more sensitive

and for your excitor test , i can say your excitor was damage , you can rewinding that standart resistance for my excitor is 20 - 25 ohm its 80 kw if 65 kw i thing it more small than that

sory if my english is bad

iam indonesian man who can spoke and write good english

hope my information use for my friend on cr 4

happy new year hope in next year more good than last

with all regards

Taufik nur hapani ( opik32@yahoo.co.id )

I would just like to say a big thank you to everybody for all your help once again.

I have managed to source a new alternator in South Africa and it will be delivered hopefully by Monday, I have also managed to arrange for my broken one to be rewired in January and I will then keep this as a spare.

I hope everybody has a worderful New Year

Best Regards

Mally

Check the harmonics in the system.

Please remember to order a spare avr card as well as things like bearings etc before you pay for the generator

dear sir.

u must checked carefully the avr u used. because mybe you are using the sub-standard. because we are in the same trouble and i discover that the avr we are not genuine.

but if you are using the right one. you must check carefully the connection that you made. i.e the exciter diode connection because it has a polarity positive and the negative. the positive side is xx and the negative is x.

and try also to test your exciter diode, the alternator it has 4 or 6 e-diode try to check each because one reason of inbalance excitation if 1 of this diode is faulty.

i hope it could help you.

more power.

Thank you for your advise, we have sorted the problem out with a new AVR and having the Generater rewired completely, everything now working well.

Thanks

Mally

Mally,

You don't tell the details of Altarnator and AVR.

Also you don't tell what kind of load to used.If load(50%) is variabling every miniuts,this is a point.

Thanks

Mamun

Yes. The equipment manufacturer can do this, the name, address and telephone number of which has been withheld from the forum.

Are you aware of the date on this subject or is there a problem with the program?