Genset

[bj]

   As cooler weather is here, and the dratted S stuff is near, decided it was time to get the Genset ready to use.
I did a little rethinking on location, (was at the shop) so now it is in the house garage.
Main reason is that most of our long power failures occur when it is around -40.  They haven't quite figured out
line shrinkage I guess.
    So, to that end, the house garage.  Breakers are right there, (warm)  gen is right there, (warm) and I am right
there. (warm)  Long story short, I don't want to drag my lazy but warm butt out in -40 if I don't have to.
    Driver is a 12.5 Briggs.  I/C version.  Gen is a Belt drive 4000w/5000 peak, but I opted for a Lovejoy style coupling.
The motor is vert. shaft, so it makes for a compact unit.  Basically 2 ft. square, 3 ft. high not including gas tank.  Tank
is 5 gallon, and remote, for safety reasons.
    Noise is handled with a pair of Acura mufflers in series, and of course vented outside.  All joints welded.
    Turned off the mains, gave it a go.  Furnace turned up, 6 lights on, Coffee pot on, (most important) and the microwave
heating a bowl of water.  It handled everything with spare, only issue being that I need to spend some time on the
governor.  Normal here is 59.9 Hz on my meter, had gen set for same, and it wanders between 59.8, and 61.  O.K., but
I'd like better.
    The other thing I had at the shop was a kill switch next to the main breaker, so no start until breaker was thrown.  I would
like that here as well, but wiring it will be a challenge without destroying drywall.
    Sorry, no pics until my camera returns.  It's in Canmore taking (hopefully) hundreds of pics of my new grandson.  No name yet,
so he is stuck with Number 9 as a nickname.
    Enough for now.

[wpowokal]

Bj you don't say if your stated HZ is loaded or unloaded but either way don't get bogged down on a HZ or two, within reason it is fairly meaningless, also did you measure it before or after the engine had warmed up well.

Allan

[bob g]

you will never get better or tighter regulation of frequency than what you have now
the briggs governor just isn't capable of better speed control.

that being said, we find 58-62hz perfectly acceptable for standby/emergency use, a bit tighter on a main genset that is powering an offgrid installation (however they are all diesel and have much more refined governors)  even the good ones have trouble maintaining between 59-61hz  (full load to no load) regulation.

just about nothing you are likely to run needs better than what you are doing now, unless
it is some finicky medical device in which case use a UPS to provide clean dead solid 60hz sinewave of low distortion.

over at microcogen.info there are many guys that would love to have as tight frequency from no load to full load that you are getting. 

i know i would be very happy with it myself as my unit swings from 58.5 to 61.5hz, and it is perfectly acceptable to me. 

bob g

[bj]

  After some playing Bob, I agree completely.   I think I could maybe gain from a monster flywheel, but it's not worth the effort.
  Allan:  fully warmed up first,  and it was about the same loaded or unloaded.  If anything, maybe the governor was working harder
unloaded.
  I was just being my usual picky self.

[taylorp035]

While bench testing my 3.5 hp briggs, the rpm goes up and down about 1% for no good reason.  The load is constant (lightbulbs), and the belt is not slipping (synchronous).  If your setup has a carburetor, then I imagine the same thing will happen.  If EFI, then the computer should be able to keep it constant, unless the position sensor is going bad.

[bj]

     Taylor: probably is the carb.  The 12.5 Briggs is a bit over-carburated.  If I was really worried, I'd fit something a bit smaller
and maybe a mixer of sorts in the intake.
     It starts very well though, just a touch on the starter, so I'm inclined to not "mess" with it.  My only other complaint (small)
is that it is a bit of a pig on fuel.  Again, typical of this series of engines.
      Now that I have it done, Murphy's law will kick in, and I won't need to use for a long time.  At -40 I don't really care how
much it uses anyway.

[ChrisOlson]

Normal here is 59.9 Hz on my meter, had gen set for same, and it wanders between 59.8, and 61.  O.K., but
I'd like better.

bj, we got a Generac EcoGen (V-Twin LP Gas, low rpm with a belt driven generator), and from the factory it was set for 60 Hz no load and fully loaded it would drop to 58 Hz.  When the inverter starts it it's normally for battery charging because the bank got too low and it only runs at about 50% load on battery charging while simultaneously carrying the rest of the house and shop loads.

So one day when the inverter started it I flipped thru the menus on the inverter until I found the gen voltage and freq.  The voltage was 242, which was OK, but the freq was 59.  So I tweaked the governor just a smidge until it was at 60 Hz with its normal loading.

That Generac engine has an excellent governor on it with very little droop under load.  But still, it varies by 1 Hz either side of 60 - that's pretty much the norm unless the unit has an electronic governor (which I would never trust for off-grid use).
--
Chris

[rossw]

unless the unit has an electronic governor (which I would never trust for off-grid use).

Why would you never trust it?

I have one and I must say, it's a remarkably solid and reliable bit of equipment.

Sorry for the blurry pic - I must have moved while taking the photo. 42 seconds of run, showing barely 1 *RPM* variation - which turns in to less than 0.03Hz variation.


This one shows adding another 2KW load (6 divisions in) - less than 0.5Hz change, and recovered quickly.

[ChrisOlson]

Why would you never trust it?

Just because I don't.  My 250 kW genset that I power my grain operation with has a Cummins N-14 525E, and it has an electronic governor.  It has been very problematic in very cold weather because the little actuator that controls the potentiometer that sends the throttle signal to the ECU sticks when it's really cold out and causes erratic operation until it gets warm in the generator shed.  I've replaced it with a new one and the new one sticks when it's cold out.

It gets down to -40 here in the winter time (and sometimes colder than that) and if it's mechanical I can make it run no matter what.  If it's electronic and it refuses to work, I can't.  We had several options when we ordered the Generac for the house and shop - electronic or mechanical governor, Battery Sentinel (which we didn't get because the inverter takes care of battery charging when it's running), we got a brushless revolving field generator vs a revolving armature generator with brushes (was more expensive), and an oil centrifuge system so it can run 500 hours between oil changes.

We opted for the mechanical governor and have been very happy with it.
--
Chris

[rossw]

It has been very problematic in very cold weather because the little actuator that controls the potentiometer that sends the throttle signal to the ECU sticks

*chuckle*. Irony++
The actuator that controls the pot - it's the mechanical part causing the problems!

and an oil centrifuge system so it can run 500 hours between oil changes.

I simply put in a larger oil reservoir/cooler. I try to change the oil at 400-500hrs, but I let it go right out one time to 1000 hrs - oil analysis indicated it was still ok, but thats past my personal comfort zone.

[ChrisOlson]

*chuckle*. Irony++
The actuator that controls the pot - it's the mechanical part causing the problems!

True, and Cummins/Onan could've eliminated that actuator if the electronic governor could send the throttle signal to the ECU by itself.  But the Cummins Celect system doesn't work that way.  On the Generac, being a LP gas engine, it has a throttle valve, which is mechanical and requires a mechanical actuator no matter what you do with electronics.  The mechanical governor is all gear driven and just a lever coming out of the crankcase that operates the throttle valve against a spring with an adjusting screw to set the freq.  No linear actuators to fail.  That's why I ordered it that way.

I simply put in a larger oil reservoir/cooler. I try to change the oil at 400-500hrs, but I let it go right out one time to 1000 hrs - oil analysis indicated it was still ok, but thats past my personal comfort zone.

It was about $200 for that centrifuge system and they're a pretty well proven system on railroad locomotives, heavy trucks and so on.  So it seemed like a good idea.  We won't even come close to putting 500 hours a year on it, but at least I only have to change the oil in it once a year with that system on there.
--
Chris

[wpowokal]

Throw away the frequency meter and just measure voltage, much less stressful.

allan

[12AX7]

I recall years ago (many) using a TV to monitor line frequency.  Way back when they used the 60 HZ line frequency to sync the vertical interval (roll).

I don't recall which indicated which..  bars rolled up line freq was low?  bars rolled down, freq was up? Then we wised up to use two TV's and watched them both for the same roll. 

[tanner0441]

Hi

I was watching a documentary last night on the history of our National Grid here in the UK and even in the 60s some of the shots you saw in the control rooms the frequency meter was heading for the 48 mark on the scale, not the 50 Hz we should be getting.

When I set generators up on the boats I used aim for the rated voltage and frequency at between 50% and 75% load.  Lower loads were usually just lighting and the frequency wasn't important, and above 75% things like washing machines, tumble dryers and fan heaters, so they coped OK.

Small generators under 5KW you put up with what you got, some you could tweak the voltage a bit but most were factory set. Petrol (gas) generators were never as stable as diesel powered, the Governor was usually a vane from the cooling fan.

Brian.

[bj]

   As usual, couldn't keep from tinkering with it.  This engine has an internal governor.  Anyway, changed the settings so the
governor was a little further open, past the middle of it's range.  That helped.  Under load it's steady, takes more load well.
   No load however, it's a bit worse.
   No more tinkering, that's as good as I could hope for.
   I had turned off the breaker at the pole this time, and left a few lights on in the shop, some in the house, both furnaces, and
of course the coffee pot.  It was much harder pressed, but still on freq, and 121/122 volts per phase.  Then the air compressor
decided it was time.  LARGE voltage drop.
   What good is a system if you can't push it a bit?  Probably should get in the habit of killing the compressor when I'm not using air
anyway.
   On to the next project.

[ChrisOlson]

bj, I'm curious, and perhaps I missed it - is your Briggs genset gasoline fueled, or LP fueled?  Is it one of the vertical shaft Intek models that comes pre-packaged in an outdoor housing?
--
Chris

Edit: I was curious because I'm not real happy with the cost effectiveness of LP gas for a standby generator.  Our Generac burns about 1 gallon per hour @ 50% load and LP gas is about $1.96 a gallon around here.  My gasoline fueled 6500 watt portable Generac burns .51 gallons per hour @ 50% load and I can get gasoline for $3.49 per gallon.  So it costs less to operate a gasoline fueled unit than it does LP here.

I had a Yanmar diesel at one point and even with a cold weather starting kit on it there was no way it would start if the temperature was below 10 degrees.  I gave on diesel standby power for us because of the starting issues.  For prime power a diesel is fine because it runs 24/7 and it only has to be started once when it's required.  But one of the selling points of the LP-fueled Generac was its efficiency and cheap operating cost.  And that may be the case if you can LP gas cheap, but we can't.

I looked at a LP fueled Briggs unit that was sort of like the Generac CorePower 7 kW.  It had an Intek engine in it and it was really noisy compared to the Generac.  I was curious if that's what you have.

[bj]

  Hi Chris--Gasoline for fuel.  This one is  built from scratch.  The 12.5 I consider a bit of a pig on gas.
It would run a bit less than 1/2 gallon per, but not much.
  Noise--yes.  Two Acura mufflers pretty much cured that.  You can have a conversation next to it, at load.
  LP prices here are worse than that, and I kind of gave up on it years ago.
  Gasoline prices here are about $1.10 a litre, and it's been lots higher, about $4.50 your gallon?  Just makes
more power, so uses less.

[luv2weld]

LP gas is about $1.96 a gallon

Must be nice. The last time I bought propane, it was $3.19 a gallon.

Ralph

[ChrisOlson]

If there was a way to convert that Generac to gasoline without voiding the warranty on it, I'd do it.
--
Chris

[bj]

Hope this works, and I have resized correctly,  Camera is back so took a pic
Didn't get around to painting the stand.  Have to add some more heat shielding as exhaust
system gets hotter than I expected.  The wall side where the exhaust exits the engine
is shielded.

[ChrisOlson]

That Briggs should be good for generator duty.  Those I/C engines have a cast iron sleeve and they're pretty durable and trouble free.  Like you say, they're a little hard on gas, but it shouldn't have a problem driving a 6-7 kW generator and still have some surge capacity left.
--
Chris