Generator Control

Hey everone hope you got all your shopping done!!!!

I was at an auction this weekend and purchased a 400 amp generator and what was left of the transfer switch/Control station. Well I had to run home and get this thing running and finally did but need some input. I had an old SLC 5/02 on the shelf and started in on it. Everything works as expected....Power goes out, Generator starts, I let it run for 10 seconds then trip the transfer switch.


Here is where I need help:
Im sending a closure to the starter for about 5 seconds and then check for output from the generator. if no output repeat. I know this is not the best way to do it and was wondering if anyone has done this befor.

Maybe I need to be watching the output for Hz and then cut out the starter and transfer at 60Hz. Was also thinking about using a pickup on the flywheel.

Any input would be usefull in spending my xmas money!!!!

Ok so a few years ago I built my own transfer switch for a yet to be purchased generator. I used a reversing hoist contactor and three relay timers (4 pole KH style). It was all done by timing and A$$uMEing that the generator would actuall start and run properly within the alloted time.

So I was planning on buying a $1500.00 auto start generator, but then my wife took my pickup to Costco and purchase the "same size" generator there for $500.00!! What a deal! Problem was it was a pull start job. After that I decided to forgo the trouble of the auto transfer switch, cement pad etc.. and installed a 220v receptical on the back of the house. Kept the pull start.

Funny story. I kept about 5 gals of gas in the generator, and another 10 gals in the shed. Wifie found that using that gas for the lawnmower far more convienent then going to the gas station. So the Big blackout comes...NO GAS. I ended up sucking gas from our fleet trucks for the stupid generator, and for my car, and for her car. It's been 25 years since I last did that, and the taste of gas hasnt changed a lick in all that time....

I couldnt pass this thing up. 400 dollars for a kohler fast response with only 300 hours on it. It did have a starting panel on it but someone yanked it off. I was reading an article on some generator equipment and it looks like they cut off the starter under 2 conditions. Time out or when it hits a certain RPM so I guess I just need to find out what RPM I should cut the starter out on and Im good to go. At that point in time I just have to put a sensor on the fly and count the pulses. Might even send that out to a PV I plan on sticking in this thing

In most cases its 1800rpm and 60HZ, you could use either or both plus a voltage reading if you want to be sure.

Transfer switches arent that hard, what you want to avoid is the possibility of the gen power and utility power being on at the same time, good idea to use interlocked contactors...unless you want to get involved with synchronizing, which can offer some payback.

The big gensets, CAT etc, use redundancy ...ie flywheel sensor, frequency and timers on the start cycle.

400AMP...this thing diesel, liquid gas, natural gas or propane? If its regular gas I would look at converting to propane or natural gas.

You have to check on how the local utility works but if you provide power to the grid you get paid for it, thats what I meant by payback.

Jason,

I'm not sure who or where, but I understand that there is a device availabe that acts as a governor, and transfer signaling. It operates by the frequency output, (60 hz). Aslo some new generators are actually like a car alternator with a solid state output of some type that produces 60 hz no matter the RPM. Kinda like an AC drive. Big fuel savers. When demand is low generator goes down to idle but voltage and hz are stable 220vac @ 60 hz. When demand goes up generator is throttled accordinly.

Just for fun, and to give me something to google..What model & output is this thing?

Mike,
Your wife mows the lawn? WOW, were did I go wrong.

The genset is a P#125REOZJB with a 4s13w alternator on it. After tearing into the lower enclosure tonight I found that it has some serious control equipment inside there. Im assuming its the equipment Mike was speaking of that keeps a constant 60Hz but because it works Im going to leave it alone "for now anyway"

Ive been looking at some of the Kohler control heads that are usually purchased seperate from the generator and what I think is that they tie into the equipment in the breaker cabinet to know whats going on out there "IE pressure, temp, RPM etc" So what I need to do is get on the phone with them tomorrow and see if I can get a diagram from Kohler.

Maybe all the parts I need are there and Ill just have to figure out how to read them into the SLC "Why buy the real control when I could build on"


The transfer switch is the easy part because I used to work for Liebert on large UPS systems "6000 Amp 480V UPS anyone!" I was just glad that I was able to save the transfer switch guts because it already has all the safety interlocks on it all I have to do is find a nice big box for it!

Oh and BTW it is Diesel. The neighbors may hate it now but wait till the power goes out this winter as it always does around here.

Most of my early controls background was in Cat Town, USA (Peoria, IL). I started there for Republic Electric (REDCO) who was finally acquired and name changed a couple of years back.

The basic CAT (and many other brands) of standard autostart panels were 7 relays, 4 lights, two switches, and a timer. Crank termination was often when oil pressure came up. Oil pressure would trigger the crank termination relay. If no oil pressure showed up, overcrank timer would shut down the process (20 or 30 seconds). If it lost oil pressure, overheated, or went into overspeed, then it would also shut down. Some fanciers options had an oil pressure timer, if it did not get pressure in ? seconds, then crank termination and oil pressure failure. Some brands, such as Cummins and Detroit, used fuel pressure for crank termination. Sometimes,n a mechanical contact on the speed switch was used, and on rare occasion, an electronic speed switch.

I did an extensive project for a prison several years ago, with load shedding, remote monitoring and switching of each building, and scada. The system consisted of two GE Fanuc 9030 plc's, a pc with Cimplicity software ($36,000+), assorted pieces of switchgear, transfer switches, and GE MultiLin relays, and the basic 7relays, four lights, and a timer. Actually, there were a couple of extra status monitoring lights.

The cranking panel could have easily been incorporated into the 9030 or into a micro plc, but one thing remains... Service Techs for Diesel engines understand relays, they can feel them close, here them click, and plug in a new one whether it is needed or not.

Anyway, the SLC should be adequet (and then some) for autostart control. A mag pickup on the flywheel should work, crank termination at say 50-75% rpm, and transfer at perhaps 55 cycles. Smaller motors can handle off frequency.

Years ago when testing the generator at Peoria Police, I would ramp the engine RPMs up and down to exercise the electrically adjustable mechanical governor. The HVAC guy noticed that he was always replacing at least one AC compressor motor the first Tuesday of the month. We also woul=nd up replacing a drive motor in at least one of the 4 20 channel tape recorders the folling day each month. I determined what was happening (some motors say 60 cycles, and just won't accept any more and any less). The problem mysteriously went away. Some folks suspected, but no one knew for sure. After that, I ramped the governor during the 30 minute warmup.

Supervisor told the local utility that we needed an hour warning on power outages to get a technician there to start generator and stand by. That also included unexpected outages, like a drunk taking out a power pole.

One day the supervisor was taking an oil sample (while the engine was running), and the syphon hose got pulled in and wrapped around the crank case. So, the Cat dealer had to schedule someone to come out and remove it. Police department proceedure mandated standby power at all times be available. So, CAT brought a generator, Civil Defense brought a generator, and Supervisor brought a 5kw generator which was setting outside dispatch with a cord running inside and running the whole time. This was in the early 80's. Talk about paranoid!!!

Perhaps Bob will check in from down under, he is the resident generator expert, hands down!

regards.....casey

Figured 125KW: http://www.kohlerpowersystems.com/pdf/G5209.PDF

http://www.kohlerpowersystems.com/onsite_diesel.htmlbb

Oh yeah. Ron has had a little experience with generators, too.

Well, actually, quite a lot.

Sorry Ron, you can be a resident expert with Bob.

regards.....casey

Mickey said:

Mike,
Your wife mows the lawn? WOW, were did I go wrong.

Click to expand...

Ok so SHE buys this house with an acre of grass. I cut it ONCE with our 20" Toro. It took two days. I told her to hire a service because that's not the way I'm going to spend my weekends. The lawn was always cut when I got home so I never knew...BTW she has great legs..

square mile = 5280*5280 27878400
640 acres per section (square mile) 43560
minus 2500' house 41060
minus 10x100 driveway 40060
minus 24x30 garage 39340
minus 10x 20 shed 39140
remaining lawn /1.66 ft (mower width) 23578.31325
miles to mow 4.465589631
2 days in linear feet 11789.15663
6 hr days (beer/mower fluid replenishment)-linear feet/hour 1964.859
mowing miles per hour 0.372132469

Someone is slacking off here!

Rod,

You forgot a few things.. I have 4 (four) kids. That means lots of toys to pick up. TWO picknic tables. Trim around the pool, playscape, swing set, three gardens, dumping the bag (if you dont bag then you clean the pool a lot), two or three gas stops....bla bla bla...

They say laziness is the mother of invention. So I attached a couple of cables to the mower that would pull it around in closing circles. It actually worked, however..my wife couldnt resist the urge to LANDSCAPE placing a large number of obsticals in the way. So that ended that, and I stopped cutting grass altogeather.

Serves her right... she ruined my ice rink with all the new trees and bushes.