Generator Behavior

thunderbird1

New Member
Oct 4, 2006
365
Pacific Northwest
I'm new to the world of generators -- a 5Kw Westerbeke. For you Sport Cruiser folks with more experience, here are two questions.

1. When AC/heat kicks in, I can hear the generator engine change speed momentarily, then return to normal RPM. Moreover, the voltage meter in my cabin drops 10-15 volts, then returns to the normal range. I suspect the amps required to start the AC is considerably higher than the 10-12 required to keep the AC running. Do your generators also bog down momentarily when high amp items such as water heater or AC come on line?

2. As I add additional high amp items, such as water heater or Microwave to the mix, the voltage meter in my cabin drops a few volts. In other words with AC only the meter registers 115, with AC + water heater it reads 110. When the Microwave is added, it drops to 105 or so. Is this the same behavior you experience with your gensets?
 
Hello,

1. I read that correct operation of the generators requires that both voltage and frequency are kept as constant as possible.' Frequency is controlled by means of the prime mover as it is proportional to the generator speed. In stand-alone applications, voltage is controlled by means of field excitation.

Output voltage is subject to changes due to variations in the generator load. These load variations affect voltage drop in two different ways. First, the load produces a voltage drop in the armature resistance and leakage inductance. Second, the load produces an armature reaction which tends to weaken the excitation field, when the load is inductive, or to reinforce it, when the load is capacitive. So, the same load magnitude may produce a different voltage drop, or even produce a rise, depending on the load nature (inductive or capacitive). Also, the load nature will affect the transient behaviour of the output voltage.
So it happens to every generator.

2. Same answer as above.

regards Peter
 
Sounds absolutly normal. Remember shore power is considered an unlimited power supply. A generator and only produce the amount for power the engine will turn. There for it's limited in the amount of electrictiy it can make. I'd recomend you run your water heater on shore power then turn it off on generator unless you need it. Some boat are set up with engine heated water. This is if you have closed cooling on your engine.

Pat
 
Yeah - It's normal. I was struggling with the voltage drop which would cause the A/C to actually go offline until I found that the SMXII on the A/C was miscalibrated so it "thought" it was not getting enough voltage when it actually was.

It's normal to see a voltage drop as you add demand. Also, you should always run the generator with some load and avoid running it with no load at all. You'll extend the life of the generator and the generator motor by making sure there is at least some demand on it when it is running.
 
Hello Thunderbird,

Also, and this is very important always allow your generator to load your battery's and always turn on your AC converter breaker.

If you don't do this your generator can damage.

And don't turn on your generator with already some AC breakers on; just turn them on if your gen is running.

Peter
 
A 5 kw genny will generate 41.6 amps at full rated output. You will get the best plug life from the motor if you keep the system running under load. Otherwise you will foul spark plugs. Westerbeke recommends you keep a 75%-80% load on the genny which equates to 31.2-33.3 amps. It is difficult to maintain these loads because appliances cycle on and off. With a water heater, coffee pot, A/C and TV running you may be in the 28-30 amp range, but eventually the water is hot and the A/C reaches the set point and power demands drop off. You need to watch your power consumption when on the genny but sounds like you are properly sized and the conditions you describe are normal. You should check for a smokey exhaust occassionally as this is an indication you are overloading the unit.
 
thunderbird1 said:
I'm new to the world of generators -- a 5Kw Westerbeke. For you Sport Cruiser folks with more experience, here are two questions.

1. When AC/heat kicks in, I can hear the generator engine change speed momentarily, then return to normal RPM. Moreover, the voltage meter in my cabin drops 10-15 volts, then returns to the normal range. I suspect the amps required to start the AC is considerably higher than the 10-12 required to keep the AC running. Do your generators also bog down momentarily when high amp items such as water heater or AC come on line?

2. As I add additional high amp items, such as water heater or Microwave to the mix, the voltage meter in my cabin drops a few volts. In other words with AC only the meter registers 115, with AC + water heater it reads 110. When the Microwave is added, it drops to 105 or so. Is this the same behavior you experience with your gensets?

Normal as already mentioned. The generator is obviously powered by an engine, diesel or gas. When appliances kick in the generator will require more power from the engine to generate the amps and maintain voltage. The engine speed to generate 110-115 volts is governed by an engine governor that is often belt driven (WB) on the top of the engine. When the generator draws more power from the engine it takes the governor a second to respond and open the throttle more to allow the engine to produce more power. That is the hesitation you notice. On a good genset it should be just a split second change as the increased amp draw kicks in. Then the governor will open the throttle more and the gen engine will run at a higher load with a wider throttle opening at the same rpm and volts.

My gen, if not fully warmed up in the winter will not start the heat cycle of the a/c on the first try. It'll bog down too much and too long and the SMX control kicks out. On the second try the start up is hardly noticeable. In the summer when hot and starting the cooling cycle that never happens, but in the winter when everything is cold and starting the heating cycle (which draws 20% more amps on start up than the cooling cycle), it can happen when I only let the gen run for a minute before turning the heat on.

I would guess that the new FI gensets are less succeptible to this because they have better and quicker throttle response.
 
Thunderbird1..... Do you have a Westerbeke or a Kohler as I did not see a Westerbeke offered on the 06 260DA? Maybe you ordered it special :smt001 If it is the Kohler then we share the same genset .... my behaves exactly as you mention it seems to take a half second to "catch up" aka increase throttle to supplement for the larger load....

We really enjoy our genset.... it sounds like you are as well :smt001
 
280 SeaRay said:
Thunderbird1..... Do you have a Westerbeke or a Kohler as I did not see a Westerbeke offered on the 06 260DA? Maybe you ordered it special :smt001 If it is the Kohler then we share the same genset .... my behaves exactly as you mention it seems to take a half second to "catch up" aka increase throttle to supplement for the larger load....

We really enjoy our genset.... it sounds like you are as well :smt001

Yes, we have a Kohler (Yanmar) also, just what you say Jeremy it react the same as thunderbird described.

Do you guy's have the same as in the pic? it's a 6,5KW

Peter
 
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I really wanted a low CO model, but Sea Ray didn't offer the option at the time we ordered the boat. So we purchased a Westerbeke and asked our local dealer to install. Plus, Westerbeke's are painted a cool red color. :wink:
 
Ia ctually hate that Westerbeke paints EVERYTHING in red after the genny is assembled. I mean even the hoses and belts were painted. C'mon ... it's a hassle when you work on them and paint chips fly off and litter the bilge all the time. Also makes the genny look worse when you wrench on it. I don't get WB on this :huh:
 
Very cool. Do you happen to have pix of the install that would have been neat to see.... especially with the boat assembled. I was surprised to not see the low CO offerings in the 2006's as well.... of course they are now available in the 2007's. Sounds like your setup rocks sir :smt001

I thought the red hoses were just custom performance parts :wink:
 
Alex D said:
Ia ctually hate that Westerbeke paints EVERYTHING in red after the genny is assembled. I mean even the hoses and belts were painted. C'mon ... it's a hassle when you work on them and paint chips fly off and litter the bilge all the time. Also makes the genny look worse when you wrench on it. I don't get WB on this :huh:

This summer Westerbeke sent out a dealer buliten to us. They no longer are paintin hoses , belts and wiring harnesses.
Touch up paint is available from your local Westerbeke dealer.

Pat
 
Here it is!
 

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They FINALLY wisened up !!

Look at mine ... a red mess !!

http://s96.photobucket.com/albums/l...00712_1024x768.jpg&refPage=&imgAnch=imgAnch17

The other thing I really dislike about my WB is teh fact that you cannot change the zink without unbolting and lifting the entire genny or removing the heat exchanger. The zink can't be pulled out because it is too closely mounted to the bottom of the genny heat exchanger and there is not enough space between the heat excahnge and the floor on wich the genny is mounted to pull a zinc out, let along put a new one in. Really bad design!! and then WB says "Check zinc monthly" IMPOSSIBLE !!
 
Alex D said:
They FINALLY wisened up !!
Look at mine ... a red mess !!The other thing I really dislike about my WB is teh fact that you cannot change the zink without unbolting and lifting the entire genny or removing the heat exchanger. The zink can't be pulled out because it is too closely mounted to the bottom of the genny heat exchanger and there is not enough space between the heat excahnge and the floor on wich the genny is mounted to pull a zinc out, let along put a new one in. Really bad design!! and then WB says "Check zinc monthly" IMPOSSIBLE !!

Count yourself lucky. I was thinking your set up looks pretty good compared to my Tiara. To check the oil on mine I have to remove a jump seat, lift the floor (another person needs to push the switch in the cockpit), remove the ladder to the bilge, kneel between the mains, (not easy) and then feel for the dip stick. Then, you need to feel for the dip stick tube and slide it back in. This takes takes about 15 minutes. Changing the impeller involves removing and replacing the entire pump assembly. It is cheaper to do this than to spend time trying to remove and replace the impeller without taking everything off. Fortunately, I don't have to worry about zincs since we boat in clean fresh water. Zincs in Lake Michigan turn a little brown, but do not corrode.
 
sbw ... I feel for you !!!

My sinc is entirely gone since the boat was in salt water for three seasons. I can get the plug/stump out, but I cannot get a new zinc in. Maybe I don't need to since we are in fresh water now too ...

Trust me, getting around in the bilge of my 340 is much more difficult than anything on my 24 foot Four Winns Vista was. I have not yet figured out how to get to the transmission drain plugs or the A/C strainer. IMPOSSIBLE !!
 
Alex D said:
sbw ... I feel for you !!! My sinc is entirely gone since the boat was in salt water for three seasons. I can get the plug/stump out, but I cannot get a new zinc in. Maybe I don't need to since we are in fresh water now too ...

You really should figure out how to reinstall them. Even though you are in fresh water there could be stray current issues that could damage your systems. In fresh water you are at less risk, but I still check the ones on my mains once a year. My mechainic who is a tiny little person can get to the one on the genny. I pay for that every other year. So far no wear, but you do need to check them because the cost of failure is too high. SBW
 

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