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vr6

i have caterpiller 650 kva  c18  
avr:VR6
when i start generator voltage increase to 600 voltage after 5 second voltage becomes 70 volt and remain at 70 what is the reason gents

Super Contributor

Re: vr6

[ Edited ]

Some more information would be helpful, like what is rated voltage of the machine.

 

Based on your description it sounds like the regulator is hitting the over-excitation limit (OEL), then shutting the regulator off, the 70 volts is probably the residual voltage level.

 

If you don't have access to the CAT VR6 manual, the VR6 is actually a Basler AVC 63-12, here is a link to a manual that will provide some additional info.   https://www.northern-lights.com/media/PDFs/manual_pdfs/AVC63-12.pdf

 

 

MikeL.

Contributor

Re: vr6

thank you for your replaying bro
that is second time this situatuion is happend at first time i could fixed it by changing external resistance but that time i want to fix it forever 
so if i change avr its not good??

Super Contributor

Re: vr6

What do you mean by "changing external resistance" did you mean changing the position of the voltage adjust potentiometer?

 

Can you answer the other questions asked?

Contributor

Re: vr6

external resistance i mean this 10 k ohm which puts on pin 6a and 7
but after cheking diodes and transformer i decided to change avr
what is ur openion about that ? changing better or needs more test 

Super Contributor

Re: vr6

[ Edited ]

I think there is a good bet the regulator is not the problem based on the info you have provided so far.

 

So if I have this right, when you start the unit it goes full field and makes about 600 VAC, I'm assuming this is a 400-480VAC machine, correct?

 

Your comment regarding the remote votlage adjust is interesting, you made a change to it's position and the problem went away, right? Have you tried installing a jumper between 4 and 7 to bypass the remote voltage adjust potentiometer, that way the AVR will use it's internal pot as reference.

 

Here are a few things that will cause an AVR to go full field,

 

Loss of sensing voltage to the AVR

Remote voltage adjust pot going open

Remote droop pot (if installed) going open

 

Have you actually tried to measure the field volts when this occurs?

 

Is it really 5 seconds before the generator output drops to 70 or closer to 10?

 

MikeL.

Contributor

Re: vr6

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Contributor

Re: vr6

bro if u look the pic
we have jumpper between  2&3 ,4&7,6a&9,
6a with 7 connect with external resistance
i chek its resistance its chaneged when we change the value of potentiometer and i negect it from avr and start generator again we have same prolem
i checked  voltage pin 20 22 and 24 read 220 volts by  at 600 volt on emcp at first 10 second then voltage becomes 35 volt on avr and 70 on emcp
avr out put f+ f- reads 24 v at 600 volt starting then become zero volt

thank you for helping
best regards