generator voltaqe

[simonmeridew]

I have a nice 4500 watt generator that I got from Harbor Freight. Starts and runs well. Wired in through a transfer box to my main panel. Problem is the voltage measured on each side of the 220  circuit is only 104 volts, so my 220 is really only 208 volts. Mostly it doesn't matter, but I have one refrigerator that won't start at 104 volts; it tries cycling on and off every couple of minutes and this can't be too good for it. I don't think the generator is some odd reworked single leg of a three phase generator that only gives 208 volts, it was a brand new unit.; for some reason the controller limits it to 208 volts. Can I raise the RPMs of the motor somehow, or will this affect the cycles per second figure adversely too?
What to do?
simonmeridew

[SPIKER]

Not sure how to help you right off, but do you have a way to measure the Hertz? (should be 60 cycles/sec +/-3~5% max.   raising RPM will raise the hertz as it is directly coupled to the engine. there should be a winding voltage control too though which should keep the voltage at or near the 120/leg for 240.   I'm not sure how the HF units do this...    May have to read up on the book, if you didn't get a book see if you can get one from them or trade for different unit.   they are pretty good about getting tools that work if ya complain about a non-functioning unit.

MarkM

[scsmith42]

We had an interesting discussion some months back regarding proper line voltages.  As I recall, the pro's on this board indicated that targeted voltage should be 118 volts per leg, plus or minus.  104 is way low.

My Onan has an adjustment where you can alter the voltage up and down.  Probably the first thing to do is to put a tach on the engine or otherwise verify your hertz.  If that's correct, your rpm is ok - you just need to crank up the voltage regulator.

One other thing - are you checking the voltage at the generator itself or at your panel?  If the latter, check it both places to see if it's in synch.  Also, cut off some of your circuits so as to limit the number of operating appliances when you check the voltage.

[Gary_C]

I had the same problem on my portable generator. It does have a set screw on the carb that allows you to increase the speed. It hasn't worked to good because the B&S engine starts to surge when I get the voltage up close to 120. To avoit spending much time adjusting the carb, I have found that if I move the choke lever just slightly, it runs fairly normal.

I believe that the voltage regulators are fixed on those small units. Yes the frequency may be off, but the only thing that affects is clocks and some electronic devices. I have run a TV on mine with no problem.

[sawguy21]

That tells me your engine is running too lean. Prolly got some mung in the main jet.
A frequency meter will tell you if the engine is at the right rpm. Turn up the urpums so it cranks out about 61 hz no load. It should maintain 120/240 VAC @60 hz to about 80% of the maximum rating if the engine is healthy. If the voltage is low there is a problem. We are seeing this more and more on the lower priced generators

[Ralph_C]

The easy way to check hertz is to plug a clock,that has a second hand into generator .

When the second hand gets on twelve watch the second hand on your watch. If it takes the clock longer to make one min. you do not have 60 cycles.  Then you need to speed engine up.

[srjones]

There's a very useful tool out there called a "kill-a-watt" (google it).  In addition to giving cycles and volts, it also shows wattage and power factor (which I still don't fully understand).    You can better under the energy requirements of the things you're plugging into your generator.

[Gary_C]

You aren't the only one that doesn't understand power factor. I could probably explain it if I thought hard enough, but I don't want to. Electric utilities just know if they don't keep the power factor up close to unity, you are getting some "free" power. You can correct it by adding capacitor banks to the power lines. If it's your own generator, correcting the power factor will allow the generator to produce a few percent more power.

sawguy21, ya, I know, but I would rather replace it with a welder generator with electric start. Maybe someday if I get annoyed enough with it.  :D

[trim4u2nv]

You could use what is called a buck boost transformer to raise or lower the voltage.  These are often used on finicky CNC equipment to calibrate the voltage on critical parts.

[Lenny_M]

 Are you getting 104 volts at no load? or under a load? How much of a load? Is the load on both legs near the same?
When i first installed my generator(10,000 watt 20.000 surge)I found 1 leg was drawing much more than the other. Use a amp meter and determine load on each leg.Then moved a few breakers in the pannel to eaquilize the load, Made a big diffrence.
I set mine to 128 volts(with engine rpm)at no load.Loaded it runs at 118-120 volts.When somethang with a large start up draw it will drop to 112 volts for a few seconds(like a 1940 somethang commercial freezer)
                                                                 Lenny

[simonmeridew]

Well I'm measuring voltage both at the generator, by plugging the vom in each 120 outlet, in turn, and also at a generator-energized outlet. The voltage is the same: 104 vac. \

Haven't tried the second hand clock trick, but will do so when I find one.

My VOM is digital; line voltage is nominal 120 vac each side, +/- maybe a half volt. , so meter is OK.

Transfer switch has wattmeters on each side, in order to balence load. Unless the rogue refrigerator(not a real old unit BTW) is plugged in I really haven't put much of a load on the either side. Maybe 800 watts, so voltage shouldn't drop much anyway. The washer and dryer work fine(gas dryer) . The microwave works but sounds funny, low fan speed and cooks very slowly, don't imagine it's good for it. Dishwasher works.
Furnace works well.

I have a meter that measures watts and also alternately amps, oof any plug in device up to 1800 watts,, by plugging the appliance in the meter and the pigtail from the meter into the normal outlet. The rogue frigerator used 300 watts or so when I last measured.  The chest freezer, plugged into the same outlet, uses 325 watts, and starts/runs well on 104 vac. Yes I've tried running each alone on generator,: same result

Appreciate advice so far and any in the future.
simonmeridew

[Dana]

There should be a specification plate on the generator head stamped with the voltages. If the unit is new, return it if the voltage is different from that listed. With that low of a voltage, you are going to burn out your pluged in equiptment if you use it very long.

[scsmith42]

Simon, I second Dana's comments.  When you purchase a brand new product, you should expect it to work correctly out of the box.  And I'd move quickly if I were you; my own experiences with Harbor Freight and their warrenty have been a tremendous disppointment.  I will NEVER purchase from them again.

If you get stuck with it, I'd start by verifying that the cylcle rate is correcct.  If it isn't, speed up the engine.  If it's a mechanical governor, I would start there by adjusting the linkage.  If it's electronic, look for some adjusting screws.

If the hertz is correct, look on the schematic for information about a voltage regulator.  Sometimes it's as simple as a winding with a slide bar, othertimes it's electronic.

But again, first see if you can get this swapped out under warrenty.  If they give you static, send their warranty service manager a certified letter, outlining the problems with the unit out of the box, and copy an attorney.

Good luck.

Scott