AVR FOR CAT'S GENERATOR 3

[wuqn]

HI
WHO HAVE THE SERVICE MANUAL OF AVR SR4 OF CATERPILLER'S GENERATOR ?

 

[powerwagon75]

Try a Caterpillar Distributor. If you have the original Parts Books that came with it, you should have an international listing of places to obtain CAT parts. Also, IF you're having trouble, try stating the situation in detail--lots of great people to help here, but not without any info.

 

[jtkirb]

I've used this regulator. Any specific questions? Good luck getting documentation. I've had better luck getting this directly from the service guys.

BTW- these regs stink. I have been swapping them with Basler SSRs for a few years now. A little more money, but they last a lot longer.

JTK

 

[rbulsara]

What kind is it? The analog one or newer CDVR (Cat Digital Voltage Regulator)?

 

[jtkirb]

I think he said SR4 which is their standard before the CDVR (CDVR is made by basler on their DECS-100 platform). The CDVR is a nice unit on the 3520c we just started up last week (volts and pf controlled on the bias signal). I really don't have a need for an SSR anymore now that cat is using a decent regulator.

 

[rbulsara]

SR4 is the type (model or series) of alternator for Cat.

You need to spec digital VR, otherwise you get analog one.

 

[choi1167]

SR4 AVR is CAT's old AVR. Now they have CDVR, VR3 or VR6. If you are referring to the old one and it's defective, you better replace it with new ones or other brand that is applicable to the generator.

 

[wuqn]

thank you jtkirb
i have some questions.
there're two "nuts" on AVR to adjust GAIN and VOLTAGE. i want to know how to adjust to get the right DROOD and VOLTAGE. And another question is : the system has three generators are paralleled. when the load changes, the power factors also change. how can i solve this problem?

 

[jtkirb]

The adjustment screws are for response to voltage changes (gain) and the center point (voltage) for the voltage adjustment. You can use a potentiometer to move the voltage up or down from this centerpoint.

The power factor problem requires power factor controllers. When you set a fixed output to parallel, that is the unity var setting when the breaker closes. When you add load the excitation needs to be increased in relation to the load.

The power factor controller can be set to a var or power factor setting (you want pf). It will constantly adjust power factor as the load varies.

We have used Basler SCP-250 power factor controls with the cat regulator you describe with good results. You need access to a current transformer for this to work.

JTK

 

[choi1167]

If this is an isolated (from the utility) system you may not need a pf controller. Your options are either go for a cross-current compensation (where the cross-current transformers are interconnected to each other) or droop compensation. The latter method requires that you adjust the droop setting of each generator while loading them individually using the same set of (KW and KVAR) loads.

 

[jtkirb]

I agree- cross current comp is what you would want on an isolated system. Go with the PF control if you are parallel. You must block the PF control if you run isolated.

 

[e5fornow]

From your description it sounds like you have a tray type Cat Voltage regulator. You can try to get the service manual but it would probably a lot easier to replace it with a VR6, any Cat dealer should be able to help you out. You will have to get a Mod kit to mount the Regulator but it is a pretty common upgrade. I would suggest upgrading all three generators.

 

[wuqn]

thank you everybody. i need more some help. How can I measure the circulation current?