Generator Hz Issues

islandguyislandguy Solar Expert Posts: 80 ✭✭✭✭
I'm starting a new thread on this subject but it's a carry over from my dead battery post since the generator was frying the equipment.

After damaging an inverter and two battery chargers I am now paying very close attention to the output in Hz.

The generator I am currently using is an All Power America APG3014. 98CC motor. The purpose of this generator is to power a battery charger, PM3-55, for a house bank of batteries and a smaller charger in a 220v inverter/charger. I was planning to change it to a PM3-45 to save a couple of amps of load, and will as soon as I get it back from repair.

With both of these plugged in I am reading 109v and around 90Hz. The meter is supposed to be an RMS, and measures 59.2 hz, from the Royal Power inverter, 59.9 from the Xantrex. Grid power also gives me normal readings.

From working in AV I am familiar with line conditioners. However I am not familiar with one that would change both voltage and Hz. I realize this might sound backwards but I'd like to look into investing a few hundred into electronics to smooth out the current coming in from these batteries.

Thanks!
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Comments

  • BB.BB. Super Moderators, Administrators Posts: 29,514 admin
    Re: Generator Hz Issues

    "Line Conditioners"--Another can of worms. There are many different types of line conditioners--So you have to make sure that you understand the terms and usage of any particular type unit.

    A couple types... There are those that are multi-tap Auto Wound transformers--These are basically variable transformers with a controller that can take (for example) 180-264 volts and control the transformer to give you ~240 VAC stable electricity voltage.

    Another is a "ferroresonant transformer".
    The ferroresonant transformer, ferroresonant regulator or constant-voltage transformer is a type of saturating transformer used as a voltage regulator. These transformers use a tank circuit composed of a high-voltage resonant winding and a capacitor to produce a nearly constant average output voltage with a varying input current or varying load. The circuit has a primary on one side of a magnet shunt and the tuned circuit coil and secondary on the other side. The regulation is due to magnetic saturation in the section around the secondary.
    The ferroresonant approach is attractive due to its lack of active components, relying on the square loop saturation characteristics of the tank circuit to absorb variations in average input voltage. Saturating transformers provide a simple rugged method to stabilize an AC power supply.
    Older designs of ferroresonant transformers had an output with high harmonic content, leading to a distorted output waveform. Modern devices are used to construct a perfect sine wave. The ferroresonant action is a flux limiter rather than a voltage regulator, but with a fixed supply frequency it can maintain an almost constant average output voltage even as the input voltage varies widely.
    The ferroresonant transformers, which are also known as Constant Voltage Transformers (CVTs) or ferros, are also good surge suppressors, as they provide high isolation and inherent short-circuit protection.
    A ferroresonant transformer can operate with an input voltage range ±40% or more of the nominal voltage.
    Output power factor remains in the range of 0.96 or higher from half to full load.
    Because it regenerates an output voltage waveform, output distortion, which is typically less than 4%, is independent of any input voltage distortion, including notching.
    Efficiency at full load is typically in the range of 89% to 93%. However, at low loads, efficiency can drop below 60%. The current-limiting capability also becomes a handicap when a CVT is used in an application with moderate to high inrush current like motors, transformers or magnets. In this case, the CVT has to be sized to accommodate the peak current, thus forcing it to run at low loads and poor efficiency.
    Minimum maintenance is required, as transformers and capacitors can be very reliable. Some units have included redundant capacitors to allow several capacitors to fail between inspections without any noticeable effect on the device's performance.
    These type of transformers are very sensitive to line frequency and would not be a good choice for use on a generator with poor frequency regulation (plus, true F.R. transformers are probably obsolete now--expensive, not very efficient, heavy/large/expensive, etc.).

    In general, a "simple" battery charger should not be very affected by frequency variation, and as long as the input voltage is within acceptable limits--I would not even bother with a line conditioner.

    If you can find a Power Factor Corrected AC Battery Charger--That would even be better. A typical PFC input power supply designed for the "international" market (battery charger, computer power supply, etc.) can take from ~95 volts to 264 volts at 50-400 Hz -- A very wide input power input and do it efficiently and cost effectively.

    The Xantrex TC2 12 volt battery chargers (and 24 volt) appear to be a very nice AC battery charger for use on small gensets (and on normal grid power).
    Auto-ranging universal input voltage (90-265 Vac, 47-63 Hz) is also compatible with a generator or other low-quality power sources

    Note, this is not "Auto-Ranging" (I don't think) where the power supply runs from 90-135 and 180-265 volts and running at 150 VAC would cause problems--This is a true "wide range" input (anything between 90-265 VAC is fine).

    Xantrex in years past has been having some sort of issues with getting these battery chargers out to their retail stores (and changes in product line due to Schneider takeover). I have no idea what is available today or where to get them (other than Google/calling Xantrex).

    Is this your generator?

    http://www.allpoweramerica.com/?_escaped_fragment_=apg3014/c1lco#!apg3014/c1lco

    I guess I am a bit confuses--Where is the 220 VAC power coming from/used? Is that from your 120/240 VAC inverter or are you using a 230 VAC genset (50 or 60 Hz)?

    My concern is the AC Generator output power quality... I don't think you are getting 109 VAC and 90 Hz... The "typical" AC Battery charger is a very simple device. And has very poor power factor:

    Here is a beautiful picture showing the relationship between voltage and current for a rectifier/capacitor front end (from here):

    Attachment not found.

    attachment.php?attachmentid=4027

    When the battery charger pulls power just during the current peaks, that can cause the AC generator output voltage to sag during these peaks--And "double" the number of peaks seen by a frequency counter (or other miss-counting events, depending on how the counter actually works). Notice the slight "shoulder" in the wave form in this picture when the current spike starts.

    Try measuring the frequency (and votlage) from the generator with a "resistive load" (100 watt light bulb, electric heater, etc.). "Non-Linear" loads can really distort the AC output voltage of under sized (or "cheap") generators.

    Here is an example measure by somebody with a "cheap" generator running "unloaded":

    Attachment not found.

    Without a scope--It is difficult to figure out what is happening.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • islandguyislandguy Solar Expert Posts: 80 ✭✭✭✭
    Re: Generator Hz Issues

    BB - Thanks, very helpful.

    this might help
    _____
    |Gen |=====110volts==={PM3-55}---{12volt house bank, now new batteries.}
    {PIC6000}
    ||||||||=====110volts====== (Ebay inverter charger)
    {Well Bank, 8D, old car batteries, whatever}___________{220V well pump}



    The generator is the one you posted. The 220v inverter/charger is only there for the well pump. I consider it a work in progress. however our well head out here is 80' and the well is an easy hundred yards form the house so I think 220 is the way to go. I am including it in the discussion because it does draw some current. I think the guy I was emailing said it was a 15 amp charger. Call it 200watts max.

    The PM3-55 is rated at 7 amps, or around 800 watts. So at around 1000 watts I'm near the max this generator can produce. When I get the PM3-45 back it's rated at 5 amps so it should knock a couple hundred watts off the draw.

    Now with both of these devices drawing power from the generator I connected my meter to the spare outlet on the side of the generator and tested for Voltage and Hz. Voltage was around 109 and Hz was around 90.

    My understanding of this type of generator means that the Hz should have dropped as well. So thanks for the explanation. There are some good portable O-scopes on Amazon. I think I'll be getting one in the near future.

    I'll check with powermax to see if their chargers can handle this kind of input. If not, I'll start looking for the Xantrex.

    I'll test the output with a light and post what I get.

    Thanks again!
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Generator Hz Issues
    BB. wrote: »
    Another is a "ferroresonant transformer".
    These type of transformers are very sensitive to line frequency and would not be a good choice for use on a generator with poor frequency regulation (plus, true F.R. transformers are probably obsolete now--expensive, not very efficient, heavy/large/expensive, etc.).l

    So sensitive that a 1% change in frequency will cause a 2% change in output voltage. I have used one along with a voltmeter as a "60 Hz. frequency meter" on occasion.
    It was free, but still a pain to move from one place to another.
    SMA SB 3000, old BP panels.
  • BB.BB. Super Moderators, Administrators Posts: 29,514 admin
    Re: Generator Hz Issues

    Be careful with O'scopes and AC line measurements. Most standard scopes have single ended outputs--The probe may have 1-20 MegOhm isolation with respect to ground... But the ground clip is usually attached to the O'scope sheet-metal (at least the old metal cased scopes) and the AC plug green wire.

    You usually do not want to get the ground clip of the probe anywhere near the AC power lines (even the ground line can have an amp or more of circulating current vs the green wire ground for the scope).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Generator Hz Issues
    BB. wrote: »
    Be careful with O'scopes and AC line measurements. Most standard scopes have single ended outputs--The probe may have 1-20 MegOhm isolation with respect to ground... But the ground clip is usually attached to the O'scope sheet-metal (at least the old metal cased scopes) and the AC plug green wire.

    You usually do not want to get the ground clip of the probe anywhere near the AC power lines (even the ground line can have an amp or more of circulating current vs the green wire ground for the scope).

    -Bill
    If the scope has differential input capability, use one probe for hot and one probe for neutral/-/etc..
    And if the wiring was done correctly, the groundING line will not carry any current or have a voltage offset from other ground points, although the groundED line might.
    e
    SMA SB 3000, old BP panels.
  • mtdocmtdoc Solar Expert Posts: 600 ✭✭
    Re: Generator Hz Issues
    inetdog wrote: »
    If the scope has differential input capability, use one probe for hot and one probe for neutral/-/etc..

    Or use an isolation transformer.

    Doesn't using 2 channels in differential mode present some common mode rejection issues?
  • BB.BB. Super Moderators, Administrators Posts: 29,514 admin
    Re: Generator Hz Issues

    An isolation transformer has its own issues... To get a good image of the true voltage, the transformer would probably have to have a pass band of 10kHz to 50kHz (to show all of the visible distortion of the AC Wave form).

    I am not sure--But a typical AC isolation transformer probably does not have that sort of band width.

    So, you would need to look at an audio isolation transformer, and get one with 600 VAC or higher isolation rating. May not be that easy to find at the local radio shack.

    Just to be very clear--There are two ways of using "isolation transformers"... First would be to get a 120 to 120 VAC transformer and put the probe on the isolated output (or get a 120v:12v transformer--probably even safer). I am not sure how good the fidelity will be, but it is probably "good enough" to see the basics of what is happening.

    A second is to use a 120v:120v isolation transformer on the AC input to the scope (and not connect the green wire). That can work but be dangerous as the "grounding clip" to the power line can make the chassis of the scope "hot".

    And a third way--There are (or at least were in my day) battery powered scopes that were OK to directly measure AC mains with (using the correct probes).

    All things being equal--I would get a cheap 120:12 or 120:24 volt (or similar) isolated step down transformer (or old door bell transformer, etc.) and connect the scope to the output of the transformer and measure the signals.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • cncbobcncbob Registered Users Posts: 1
    Re: Generator Hz Issues

    Have you checked voltage and Hz with out anything plugged into generator , if not ok try adjusting RPM of generator up or down . also when you apply load to generator do the readings change , load may change RPM . I have seen on some generators when RPM not at rated speed you get a harmonic hz reading
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Generator Hz Issues

    You know, if I had a generator that put out 109 V @ 90 Hz instead of 120 V @ 60 Hz I'd buy a new generator rather than try to correct the output of one that's obviously defective.

    But hey, that's just me. :p
  • islandguyislandguy Solar Expert Posts: 80 ✭✭✭✭
    Re: Generator Hz Issues
    You know, if I had a generator that put out 109 V @ 90 Hz instead of 120 V @ 60 Hz I'd buy a new generator

    Of course. But since I am still learning I'm not sure if this Gen is defective, or only outputting this waveform under these conditions.

    What I am looking to do here is set up a 'battery charger' generator that will only be used to bring up the battery banks. I need it to be able to run on minimal fuel and around 800 watts is good for output. The only good thing about these generators is their fuel efficiency. I've looked at marine chargers, diesel engine and 12v alternator for charging. While a nice unit the $4K price tag is making me look elsewhere first.

    It doesn't look like there is an easy way to rebuild the waveform. Even with transformers the energy loss in conversion would require a larger generator and defeat what I am trying to do here.

    I have a small windmill 400 watts going in next month so we'll see how much that helps. Energy draw on the house bank is under 4Kw a day so even 200 watts in should make a difference.

    Appreciate the input.

    Thanks!
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Generator Hz Issues

    A good generator puts out "proper" power with no load on. Add a load, of any kind, and it still puts out proper power. The Voltage and frequency should only shift slightly, if at all. Current goes up; everything else remains stable. If the current goes up too high the over-current protection should trip and shut down power.

    Not sure where you're at or what fuel you need to use, but a Honda EU1000i puts out up to 800 Watts, is extremely fuel efficient and quiet, and shouldn't cost much more than $1,000. For occasional use battery charging it would be my choice. In fact it was. Then I got the 2000 model when I needed even more capacity.
  • islandguyislandguy Solar Expert Posts: 80 ✭✭✭✭
    Re: Generator Hz Issues

    The 2000w gen needs to run around 10 hours a day to keep up with energy usage at this location.

    Because the generators here are being used to run battery chargers the larger generators on site just waste gas. Difference in fuel use between the 2000w with a 98cc motor and 3500 wen is around $200 a month. So even if these last for two months I'm ahead.

    I've no problem going with a better generator, except this is a shared site. Unfortunately if I am not there to do the maintenance it doesn't get done. So we have gone through three of the APA 2000w generators this year. At the moment that's my major problem, convincing the other people there to take care of the generators.

    Currently I know for a fact that even with the low oil shutdown feature of the generators if you let the oil run down till it shuts off, the generator is already damaged. do that two or three times and it goes to the spare parts bin.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Generator Hz Issues

    Oh boy! Nothing like having other people working with the same equipment to guarantee something to go wrong. :p

    I just think that if you have a gen that's putting out "wrong power" and then try to correct it with some other device you'll probably lose more power than you'll gain, and the money would be better spent on getting the gen fixed/replaced rather than trying to change the power it produces.

    Or maybe spend the money on smacking some people up the side of the head so they stop breaking things. :p :D

    I just bought a seized Honda 3500X for cheap. If I ever get my left arm back so I can work on it it should be interesting to see what abuse it suffered to put it in that state. They claimed the oil was "kept up" but as with your situation admitted the low oil sensor had shut it down "a few times". I wonder if they ever changed the oil, or just kept adding to it? Know what I mean? :roll:
  • BB.BB. Super Moderators, Administrators Posts: 29,514 admin
    Re: Generator Hz Issues

    What exactly is the 10 hour day load in Watts (and peak watts, if surge is important)?

    The inverter/generators like the Honda (Yamaha and others) are usually more fuel efficient when operating at less than ~1/2 load vs the standard fixed RPM genset.

    Call the eu2000i running 9.6 hours at 400 watts for 0.95 gallon tank:

    400 watts * 9.6 hours * 1/0.95 gallons = 4,042 Watt*Hours per gallon

    Assuming 10 hours running at 800 watts:

    800 watts * 10 hours * 1/4,042 WH per gallon = 2 gallons per day or ~60 gallons per month

    Looking at the WEN 3500 (guess this one) is 3,000 watt nominal output, 4 gallon tank, 11 hours at 1/2 power:

    1,500 watt * 11 hours * 1/4 gallons = 4,125 Watt*Hours per gallon

    So, the WEN 3500 when operated at 1/2 power (1,500 watts), uses about the same amount of fuel (per kWH) as the Honda at 400 watts (Honda becomes more fuel efficient at higher loads--so using the 400 watt gph for 800 watts should be conservative).

    The WEN when operating at ~1/4 power, probably is closer to 2,000 WH per gallon -- Or using 2x the fuel as the Honda eu2000i.

    So--If you could up your average load to ~1,500 to perhaps ~2,400 watts (and the WEN could handle it)--You would cut your battery charging run time to ~5 hours per day (or 10 hours every other day) and come out even or ahead with the WEN.

    However, if your average loads are 800 watts or less, then, you are correct--A smaller/fuel efficient genset will be a better choice.

    There are not a lot of "high tech" programmable battery chargers out there (Xantrex makes the TC2 family--but over the years, not sure how "real" a product series they really are)... But there are a fair number of programmable inverter+chargers that could meet the bill (program AC Generator input size to share AC loads and battery charging duties up to the ability of the genset)...

    What are your average load/gallons per day or per month you are looking at?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Generator Hz Issues
    I just bought a seized Honda 3500X for cheap. If I ever get my left arm back so I can work on it it should be interesting to see what abuse it suffered to put it in that state. They claimed the oil was "kept up" but as with your situation admitted the low oil sensor had shut it down "a few times". I wonder if they ever changed the oil, or just kept adding to it? Know what I mean? :roll:
    Also if the generator was not mounted level, the oil level in the crankcase might have gotten even lower before the low level or low pressure switch tripped. Is that engine pressure lubed or splash lubed or some combination?
    (I had a nice (but cheap) Generac portable that just would not start for me even though the oil level was OK. Embarrassed to realize that I leveled the generator when filling the oil and had it tilted when I was trying to run it.) When I moved it around trying to figure out why it would not start, it would suddenly start working again. Now I know to keep an eye out for the indicator light on the oil level/kill switch flashing while cranking.
    SMA SB 3000, old BP panels.
  • islandguyislandguy Solar Expert Posts: 80 ✭✭✭✭
    Re: Generator Hz Issues
    BB. wrote: »
    What exactly is the 10 hour day load in Watts (and peak watts, if surge is important)?

    average loads are 800 watts or less, then, you are correct--A smaller/fuel efficient genset will be a better choice.

    What are your average load/gallons per day or per month you are looking at?

    -Bill

    Bill, thanks.
    I am tracking energy use with the Effergy gateway. Not counting the H2O Bank.

    Daily use averages 3.5Kw. When there is no use at the house, just comcast box, routers Wifi etc the draw is around 100 watts. Evenings the usage goes up to 250 or 300 watts. Led light bulbs and the 46" LED Vizio TV that draws less than 60 watts. The inverter is an MSW inverter and the Effergy and the inverter don't display the same numbers so take usage as approximates.

    In the AM the Small gen gets loaded with 1.3 gallons of gas and allowed to run out. Same in the evening. So call it about 2.5 gallons per day. for maybe 3.5 KW. Probably another 1 Kw going into the H2O bank but I am not monitoring that yet.

    In the Past this location had a 6Kw and an 8Kw Generator. One of which was running during the day to provide 220v for the well. And the 110 power for the house.

    Monthly fuel use is a little better these days.

    Edit note: Bill the surge is handled by the oversized Inverters. The PIC6000 is supposed to surge to 12K. My theory here is that the generators power the battery chargers and the inverters are sized up to handle the heavy loads. So far this is working for laundry days, vacuums etc.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Generator Hz Issues

    You're making the standard mistake of leaving out the time designation. You use 3.5 kW hours per day, which is not dependent on the Watts used at any given time. If the maximum Watts drawn is only 300 you certainly don't need a large generator to supply that. Although you may need a large gas tank to supply the Watt hours. For example if that 300 was for 24 hours it would be 7.2 kW hours, but the load itself could be supplied by an 800 Watt gen like the EU1000i.

    Just trying to keep the terminology straight here. :D
  • BB.BB. Super Moderators, Administrators Posts: 29,514 admin
    Re: Generator Hz Issues

    With the eu2000i, you could probably get your fuel consumption down to ~1 gallon per day... Not sure is an eu1000i would save you much more in the way of fuel--really depends on your average loads (and the eu2000i would give you better surge for starting a fridge/etc.)...

    Another neat thing about the eu2000i--They have an internal fuel pump that can draw a vacuum in the fuel tank. Replace the cap with a barbed fitting and gas hose--And it can siphon from a 5 gallon gas can--So you don't have to refill the genset 1 gallon at a time.

    http://www.wisesales.com/duration-power-dual-feed-extended-run-fuel-tank.html

    You can buy a modified fuel cap on-line (you don't have to buy the above kit--a bit on the pricy side).

    http://www.skoolie.net/forum/viewtopic.php?f=11&t=53165

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • islandguyislandguy Solar Expert Posts: 80 ✭✭✭✭
    Re: Generator Hz Issues

    Wow, fast replies.
    First average load is probably 200 watts.Most of the day the Effergy is reading 100 watts or so. Not counting well pump.

    The idea is that the small gen run in the morning for around five hours to bring both banks up. The again in the evening to do the same and offset usage.

    Now, if I could get fuel usage down to around a gallon a day this looks good. From what I read inverter Generators have the ability to run at 1/4 load.

    Still trying to wrap my head around Kilowatt hours and Kilowatts. If my hourly use is around 200 watts per hour then its 1/5 Kilowatt hour. and if my daily use is 3.5 Kilowatts then . . . . . .?
  • BB.BB. Super Moderators, Administrators Posts: 29,514 admin
    Re: Generator Hz Issues
    islandguy wrote: »
    Still trying to wrap my head around Kilowatt hours and Kilowatts. If my hourly use is around 200 watts (watts only, no hours) then its 1/5 Kilowatt hour (0.2 kWatt*Hours). and if my daily use is 3.5 Kilowatts (3.5 kWH) then . . . . . .?

    Watts is a "rate" (like miles per hour). (watts is already a "per time" unit)

    Watt*Hours is an "amount" (miles driven). (WH is Watts*Time used--120 watts * 10 hours = 1,200 WH = 1.2 kWH)

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • ChrisOlsonChrisOlson Banned Posts: 1,807 ✭✭
    Re: Generator Hz Issues

    Can someone explain where this 90Hz is coming from? If it's a 2-pole generator the engine is turning over 5 Grand? And the rod ain't hanging out of a hole in the block yet? :confused:

    --
    Chris
  • BB.BB. Super Moderators, Administrators Posts: 29,514 admin
    Re: Generator Hz Issues

    See this post:
    BB. wrote: »
    Here is an example measure by somebody with a "cheap" generator running "unloaded":

    Attachment not found.

    Without a scope--It is difficult to figure out what is happening.

    The multiple voltage spikes because of possible issues with Alternator (poor connections, bad design, something wrong with voltage regulator, etc.) can cause a frequency counter to "miss-count".

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • islandguyislandguy Solar Expert Posts: 80 ✭✭✭✭
    Re: Generator Hz Issues

    When the battery charger pulls power just during the current peaks, that can cause the AC generator output voltage to sag during these peaks--And "double" the number of peaks seen by a frequency counter (or other miss-counting events, depending on how the counter actually works). Notice the slight "shoulder" in the wave form in this picture when the current spike starts

    So my understanding of this is that my meter is counting the frequency twice. This makes sense because with the loads on it the motor slows down and the voltage dropped to 109.

    RPMs pick back up as the voltage gets to 13.2 or so.
  • ChrisOlsonChrisOlson Banned Posts: 1,807 ✭✭
    Re: Generator Hz Issues

    Ah, OK. A cheap wound gen head with probably 20+% THD. I think I'd recommend getting a different genset.
    --
    Chris
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Generator Hz Issues
    ChrisOlson wrote: »
    Ah, OK. A cheap wound gen head with probably 20+% THD. I think I'd recommend getting a different genset.
    --
    Chris

    That was my suggestion as well, Chris.

    We're just simple. :p :D
  • islandguyislandguy Solar Expert Posts: 80 ✭✭✭✭
    Re: Generator Hz Issues

    Currently looking at the Yamaha EF1000is. Some users claiming 8000 hours on it.

    With charger loads sized at 800 watts this should work.
  • BB.BB. Super Moderators, Administrators Posts: 29,514 admin
    Re: Generator Hz Issues

    I don't have an scope images of really bad generator waveforms... They can look almost like two 60 Hz wave form offset by a 1/4 cycle. And there are other ways of messing up a wave form:

    Attachment not found.

    This is from an electronic florescent ballast "flat topping" the voltage wave form... But also notice the "ringing"--Something too that can confuse a frequency meter.

    All this is just guess work--Until you can do some further debugging (scope picture, or try a resistive load to "stabilize" the generator output--100 watt filament lamps where used very commonly--try to buy one of those now)--I am not sure I am being very helpful in "fixing" your difficulties.

    Sorry,
    -Bill

    PS for Chris: These are just Googled examples of "poor alternator output" voltage wave forms that are examples of why a simple frequency counter can be miss-lead by non-sinewave voltages. I have no idea what the output of this particular genset may be.
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • islandguyislandguy Solar Expert Posts: 80 ✭✭✭✭
    Re: Generator Hz Issues
    ChrisOlson wrote: »
    Ah, OK. A cheap wound gen head with probably 20+% THD. I think I'd recommend getting a different genset.
    --
    Chris

    By this you mean Total Harmonic Distortion?

    For my use I just need to run battery chargers without damaging them. Anything important is running off the Xantrex.

    So what I am currently working through is; just enough generator to put out 400 to 800 watts for around 10 hours a day.

    And thanks, because I do appreciate constructive criticism.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Generator Hz Issues

    The thing is that the battery charger, any standard battery charger, will not like this "apparent" high frequency nor the low Voltage.

    Now if you had a way to rectify it directly and regulate the output through a buck converter say ...
  • ChrisOlsonChrisOlson Banned Posts: 1,807 ✭✭
    Re: Generator Hz Issues
    BB. wrote: »
    PS for Chris: These are just Googled examples of "poor alternator output" voltage wave forms that are examples of why a simple frequency counter can be miss-lead by non-sinewave voltages. I have no idea what the output of this particular genset may be.

    Yes - I thought it might be actual 90Hz output and then your electric motors would be screaming (if they didn't burn up first) and the engine would be done by now.

    That generator just has a cheap core in it and you got eddy currents in the core causing repulsing magnetic fields to the rotating magnetic field from the rotor. The weird flux lines cause all sorts of harmonics in the output. There's no real good way to fix it.
    --
    Chris
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