guidance needed to parallel 2 drash gen sets together

[Poccur]

I am not saying the units cannot power the welder,I am saying that by the time it is responding to the load you are already ending the weld. Think of the gen like the cruise control on your car, when you hit a hill the speed drifts down a little till the cruise kicks it down and gives it throttle to maintain speed. The gen does the same, the load hits and the voltage sags a little as the generator responds and spools up. That momentary voltage sag as the unit responds might be the source of you poor weld.
Have you tried doing a longer duration weld to see if it improves? That would prove that the gen is recovering and voltage and freq are getting back to normal.
I am just speculating too

What is the model number of the GAC controller you have in that unit?

 

[rsms]

Do 2 generators running in parallel actually have 2x's the power output as a constant and share the load equally or does the 2nd generator only have an increase in output after the 1st generator reaches it's peak output? If they share equally would the load requirement be 1/2 that as just 1 generators, my thoughts were it wouldn't take as much of an extra bump in fuel as both generators combined output at low throttle would be possibly close to 1 generator at full throttle which on paper meets the requirements of the welder (208v 60a service) The weld time is done via the PCM not by a trigger you can hold to prolong duration and has very little adjustment manually.
The governor is a GAC model#ESD5520E

 

[Poccur]

When they run in parallel they should share half the load each...I am tracking what you are saying, they would each take a smaller bump as the load comes on...could be...but we can work with just 1 generator for now till you get the PPDU ...

That governor controller has a couple of black plastic circles on the right hand side about the size of a quarter...if you pop off the top right one there should be 2 blue squares with brass adjustment screws and two black dials with white arrows...Let's concentrate on the black dials.
Left black dial is gain and the right one is stability. The gain is the amplification of the signal coming from the magnetic pickup, the unit is working so that will not be anything we need to worry about. The stability is the ability of the unit to handle an electrical load. If the engine is too stable it will run lovely and smooth but when you apply a load the engine is slow to respond and bogs down, the volts fall etc....if it is too unstable it 'bounces' or 'hunts' when it has no load on it but when a load is applied it can respond much quicker...
Take a small adjusting screwdriver and turn the right hand dial clockwise slowly, that increases instability. When you set that governor you normally dial it up till instability happens, then dial it back down till you get stability, then go 1 more notch down. If it was mine I would edge the instability up until you just start to hear the instability in the engine. Then try the welder again...

 

[rsms]

I did notice those before but was unaware of the what they controlled so thanks for that. I remember seeing the screws but they must be factory preset as mine have a green epoxy dabbed on to them to make them tamper "resistant". Tomorrow when I get a few minutes I will give this a try. I believe these are only for applicable when running in parallel but I also have a GAC part# LSM101 load sharing module and a GAC part# SYC6714 synchronizer.

 

[Poccur]

Really? Can you post a pic of the epoxy please?
Right so the SYC6714 will get the two gens in phase so the breaker can be thrown to bring them together and at that point the LSM101 will take over to allow the comms cable to keep them in sysnc so they can share the load and run in parallel...

 

[rsms]

It looks painted on with a brush. In the lower hole you can see the adjustment screws, not so much on the upper. Any thoughts or concerns?

 

[Poccur]

Oooh, they were serious about keeping you out huh?
No, that is slightly different to what I described, that is the unit for low current fuel actuators...but the same dials do the same stuff.
I would be real careful picking that goop off. If it is waxy and you can move it with a finger nail that should be OK but if it is epoxy and set hard I would not dig too hard incase you dislodge the potentiometers that are soldered to the PCB...

 

[rsms]

I was looking at it a little harder this morning and I'm a little concerned about the potential for damage occurring trying to remove it. It is a very hard and it bit very well to the board. I was hoping since it was so hard it might be brittle and break off easily but no such luck. What do you think my chances are if I go ahead and purchase the PPDU and try to run in parallel?

 

[Poccur]

Could do, the PPDU can be a pricey item to get IF you can find one....that Gov controller sells on Ebay just over $100...You could check that it is not 'gooped' on the dials before you buy it and just swap it out for a new Gov controller...

 

[rsms]

got it and its good reading!!!

 

[rsms]

Just a quick update after several months of collecting pieces....I got all of my cables built, acquired a PPDU and the correct parallel cable. Yesterday I finally tried to run everything together to satisfy the quick load requirements to my spot welder and it did work. I just wanted to give my many thanks to everyone who supplied me with much needed knowledge and guidance to get this done. Once again Thanks!!!!

 

[dangier]

The class I was in at Belvoir had a student blow the back of a turbine generator out through a window at the generator building with an extreme (blew the exhaust duct work apart), booming start. Took couple of hours for the DI to get his feet back on the ground. Never saw the student again. Made the rest of us think a lot before hitting that start switch....

((The instructors mindless screaming went on for a while)) Yea, something like that!!!!

 

[Guyfang]

Nothing like a booming start to get you heart beating a bit faster!

 

[Suprman]

I have a way to parallel these units now. Have dual contactor boxes that will allow for bringing both gens online to the load one at a time. The 2 gens would need to be operating in parallel mode with one as master. The contactor box would need some minor modification to make this work.

 

[rsms]

I ended up buying a PPDU a while back and I believe I bought a parallel cable from you on fleabay. After making a couple of small changes in my PPDU I got everything up and going. I have 6 of these rigs and I'm working on getting them ready to work as stand alones but I might have an interest in another box depending on what you have. I do possibly see a need for another on larger jobs. Can you post a little info about what you have such as input and out put connectors and individual circuit & total amp ratings

 

[Suprman]

Have boxes with dual 350a contactors. Made to switch the load back and forth but with some minor mods could be used to bring each one online one at a time. Gens would have to be in synch already with the comm cable between the two. I have the comm cables also. I have some of the ones made for paralleling 15 & 30 kw gens they use the same contactors inside.