guidance needed to parallel 2 drash gen sets together

rsms

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Hello to all, I have 2 identical drash trailers and I'm wanting to parallel the two of them together. Both are 23kw Applied Companies generators (best I can tell) and they are set up to be able to run paralleled as they have electronic governors and parallel cable outlets. I just received a parallel cord but I'm not sure if this is all that will be required to make them work together. Although I'm very mechanical skilled my knowledge of electricity is very limited. I'm also wondering if once they are paralleled will I have to run an output from both generators to a distribution panel to achieve the combined output or will my gen A output be able to provide full power. What I'm attempting to do is have a temporary 3ph 60A service capable of running a large spot welder. The welder requires a 60a service which a single generator is capable of producing but due to the quick on/off load of the spot welder the single generator doesn't ramp up fast enough produce. I'm hoping with the 2 generators paralleled I will be able to do this. Any other advice on my situation would be welcomed.
 

Suprman

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Applied is Applied and Drash is a different company. I know GP listed them as Drash. They appear to use the same paralleling cable that the TQ gen series use. The paralleling cable is only synchronizing data between gens so one gen can match regulation for the other. You will have to use both outputs. I'm not entirely sure how to do that part though. 60a per phase is a lot of power. The two gens together should easily do it.
 

Guyfang

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Normally the output cables from both gen sets are hooked to a common buss bar. The para cable hooked up, and then gen set 1 started up, and put on line. Then you start gen set 2. Both sets need to be switched to the para mode, and then the para lights will start flashing. When you have adjusted the frequency on gen set 2 properly, and the lights go out, you turn on gen set 2's output load contactor. The combined output will, (or should be if everything is in order) available at the common buss bar. The manuals for this procedure should be read, and that will clear up any misunderstandings in my explanation.

This is a very simplified explanation. If you don't read up and get smart on the whole thing, it may not go so well. And of course, safety first!!!!!!!!!!!!!! We always and I mean always, put removable fuses between the common buss bar and the load terminals of both sets. Grounding is also something to pay attention to, as well as safely enclosing the common buss and output from the common buss. Cable size is also important. Please get smart before you try this out. Could save you lots of money and keep someone from load testing his, (or her) heart. Having been hooked up to electricity twice in my life, and not been able to do much about it, I tend to be very careful.

Sadly, everyone looks at this type of equipment and called it Drash. Far from it.
 
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TrailLifeBill

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These don't have the synch lights. It's more civilian generator than military.
View attachment 660017
Same principle applies - as Guyfang stated, the manuals for the whole procedure need to be read - and understood. I used to be a maintenance electrician at a hospital where we had parallel gensets. From a 20,000 ft level, the procedure looked exactly as he describes - however, the specifics will vary from manufacturer to manufacturer. If you can't obtain the manuals for your specific gensets describing how to parallel them - and commit yourself to learning the procedure thoroughly, then you shouldn't attempt it. We parallel tested our generators weekly, and the pucker factor is great when throwing the second generator online - if anything isn't correct, the results can be disastrous.
 

rsms

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I'm very with you guys on reading up on correct procedures, I've contacted Applied and haven't had much luck in obtaining a manual and have not been able to find one posted here on SS or online. Any suggestions on how to locate a proper manual? I was thinking both outputs would have to be connected to a single distribution output and then connected to my welder from there. The machines do have a parallel procedure listed on them and it did state hooking both generators up to a PPDU first step. Not sure on this acronym, the (2) "P" kinda thru me. I believe it stands for Power Distribution Unit and the second P maybe for dual power inputs? The picture Suprman posted is the correct panel on my machines. I bought 4 of these machines for another project I'm putting together and will be using UEC connectors along with the correct size cables to transmit power. I've also acquired the correct Pico crimper and dies to facilitate proper crimps (I'm in the tampa FL area if anyone would like to use it also). I was thinking DRASH was an acronym for a this type shelter/ECU/gen set trailer in general, I must be incorrect with this? I have a lot to learn I see LOL
 

Suprman

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I have a bunch of these they are nice gens. I have the correct output cables for them also. I have spoken with Applied they emailed me the hvac manual they said the gen was subcontracted thru a different manufacturer and that he didnt have the tech manual on hand. Drash was the first ones (that I know of) to make the gen/hvac on one trailer like that.
 

rsms

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Did you build your own cables or were able to find them as surplus? If you got them as surplus I'm guessing did you did so on GL? I've been searching for them and haven't had any luck, that's one of the reason I bought a crimper. I would much rather be able to find them as surplus if possible as I will need several also and new connectors even at wholesale are expensive. Do you have a specific part# for the cable assembly that might aide in a search?
 

Guyfang

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Same principle applies - as Guyfang stated, the manuals for the whole procedure need to be read - and understood. I used to be a maintenance electrician at a hospital where we had parallel gensets. From a 20,000 ft level, the procedure looked exactly as he describes - however, the specifics will vary from manufacturer to manufacturer. If you can't obtain the manuals for your specific gensets describing how to parallel them - and commit yourself to learning the procedure thoroughly, then you shouldn't attempt it. We parallel tested our generators weekly, and the pucker factor is great when throwing the second generator online - if anything isn't correct, the results can be disastrous.


Just got to tell this story.

In 1973 I went to AIT for Power Generation at Ft. Belvoir, Va., Home of the Engineers!!

During the school, we learned many things. How to parallel was one small part. One of my fellow member of Class. 4-55 was a not so young draftee. He was from Greece. His english skills were on par with my brain surgery skills. We went to class one day to learn how to start, stop, parallel and shift the load from one generator to the other. It was on the 750 KW Power Station. To do that, we needed a load. Several hundred KW of load. The Power Generation school used the Ft. Belvoir itself, for a load. We were supposed to go from grid to set one, and then bring up set two, parallele the two sets and take set one off line. Then put the school back on grid. Easy. Can't screw it up.

The instructor went over it three times. Asked if anyone had a question. No one raised their hand. The Greek, (that's what we called him) was in the back of the class and was about ready to go to sleep. The instructor saw him and told him to "Come up her you shi~ Bird!" He asked the Greek if he understood how it all worked? "Yes". Do you have any questions? "No". "Then show the class how its done." Several people tried to explain to the instructor that Yes and No had about exhausted the Greek's english abilities. But to no avail. "Well, do it!" screamed the instructor. Everything went well, at first. He got set 1 started right, (a wonder in itself) then flipped the parallel switch on. The lights blinked super fast! He adjusted the freq down and got the lights to slow. All he had to do is wait till the lights were out, and flip the AC output contactor on. But sadly, instead of turning the output contactor on when the lights were off, he did it when the lights were on! And there we sat, in the dark. The whole Ft. Belvoir sat in the dark! The instructors mindless screaming went on for a while.

We didnt notice it was dark for a few minutes, as we were somewhat blinded by the fire works in the control panel. It was covered in plexiglass, so you could see things happen in there. And did we see things happen! It was so impressive, that I never paralleled again without thinking and seeing that image before my eyes.
 

Poccur

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If you parallel the two gens you will not decrease the response time of the fuel actuators..you will likely have a bigger generator that still does not respond quickly enough...what happens with just one gen? Does it pop the main breaker?

FYI, those gens use a parallel cable and a distribution box for parallel work...
 

rsms

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The problem was not tripping a breaker, I didn't have sufficient power to perform a quality weld. The spot weld process happens very quickly and I believe the generator does not have the amperage needed at it's base idle. The engine will start to lug as the weld starts and by the time it increases the fuel to boost RPM's the weld process is timed out and thru. I'm hoping (and could be totally wrong) the 2 generators at base idle together produce the amperage needed to complete the weld. I already have the correct parallel cable and believe I found the correct distribution box. I do not know if I'm correct in my assumption it will work though. Any insight is greatly appreciated
 

Poccur

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My concern would be that you would still take the same amount of time to open the fuel actuators if they are in single or parallel mode...and still get the same results....
Now if you had a way to pre-open the actuators...maybe a resistive loadbank to preload the engine then disengage that as the welder fires...
 

rsms

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would you believe the amperage would be doubled in parallel operation at any given RPM? My generators are on ECU trailers and I have thought about running 1 of the A/C units to preload the generator once paralleled. I wasn't sure if this would help though as the generators might only be producing what was called for at that given instance. The total weld time is roughly 1 to 2 seconds so there isn't much time for things to compensate for the additional load.
 
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Poccur

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I think you are mixing potential power with what I am pushing at, which is the ability to respond to load change. I have a little experience with similar generators and assuming there is not a quantum difference…
When a load is applied then there is a requirement for more amps which causes the voltage to sag. In response the voltage regulator attempts to push the voltage up, this translates into a larger electrical field in the generator which then makes the generator harder to turn. This then slows the engine, the governor controller picks up on this from the magnetic pickup and sends a signal to the throttle/fuel actuator to open further and maintain engine speed as the load is applied. All that happens in a fraction of a second as you apply your load.
If you are getting a poor weld due to voltage sag as you strike the welder then this could be due to the response time of the generator as it tries to respond to the sudden load increase and not a factor of the power that is available.20kW or 40kW, if that fuel actuator takes 1 second to respond then it takes 1second.

What governor controller do you have in that unit? I know the GAC controllers have a stability adjust which allows you to make the unit more responsive to load changes. The engine ‘bounces’ or ‘hunts’ a little offload but it can take a load much quicker…
 
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rsms

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This is an all new learning curve for me and I by no means have an opinion I would trust as to the fix for what the issues I'm having is. The governor controller is a GAC electronic controller and one of the 1st things I did was to verify the ramp up controller was set for the smallest time delay available. I would believe there is a fix either by paralleling two of these smaller generators together or operating off of a much larger one. If I'm understanding you correctly is it your opinion the (2) 23kw's wont be able to satisfy the welders demand? If so do you think a single 185kw generator would? I do have one of these also but I have a couple mechanical issues with I that need addressing. If there is a way to use the (2) 23kw's that would be the preferred method for me.
 
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