Harbor Freight5 ton elect splitter on a generator problem

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DodgyNomad

Minister of Fire
Dec 19, 2009
689
West Michigan
No problem. Your results may vary. I'm not an authorized or licensed anything, just a guy who has worked on a lot of this kind of stuff over the years. Always use caution around a generator, that's enough amps on tap inches away to kill you, so be careful.

Hoping the cap and the gov adjust will be enough to run your splitter.

And those little tachs are pretty darn cool, and they include an hour meter that only counts the hours when it detects spark, so a good little device to add to your generator permanently. If there ever was a machine that we should watch the hours on, it's a portable generator, even just for oil changes. I stick those little tachs on everything that needs monitoring.
 

DodgyNomad

Minister of Fire
Dec 19, 2009
689
West Michigan
Last thing to mention. People don't realize how hard it is on running certain devices under the designed volts and hertz. Electronics hate it, so do certain styles of motors, microwaves, etc. I'd rather run one a bit over 120/60hz than a bit under. Going under really shortens the life on a lot of things, IMO.
 

rodneygt

Member
Jan 18, 2013
27
They sent me the wrong capacitor so I ordered one on amazon that had a lot ofreviews for use on the harbor freight splitter. It wont be in till next friday. Just to test it out, I split a couple pieces of wood and it did fine. But it was fairly random so I'll need to do a good bit before I can say whether or not the problem is resolved.
 

oilstinks

Minister of Fire
Jan 25, 2008
536
western NC
I ran a small job smart compressor on a 3500 watt champion gen. Running amps was somewhere around 4-5 range. Would stall the generator as soon as it Tried to start. Fortunately for me the governor linkage was easy to access and we were able to get a little more effort out of the generator to get the compressor started.

The way it was explained to me was that 3500 was the rating for the whole unit...that is to say half went to the 240v plug so 1750 for the 120’s half to each circuit gave me 825 watts on each 120v plug or 6.8 amps. I’m sure start up was way over that...

some Inverters are rated the same way but that’s a headache for another day.
This is enlightening.
 

FlyFish'n

New Member
Oct 23, 2021
62
OH
This is enlightening.
According to the HF manual, the splitter requires 12A. I have Porter Cable 5250 watt generator I bought after Hurricane Katrina in 05.. So I took the generator and the splitter where I'd cut up some wood instead of bringing the wood back to the house where I've used it in the past. Sometimes, the generator was having a hard time getting the motor on the splitter to spin. Sometimes it would start up ok. But it got pretty frustrating. I tried both outlets on the generator and with and without an extension cord. It was frustrating enough that I eventually just brought it back home and plugged it in where it worked fine.

So, I've read of people using generators even half the size of mine to run these splitters. 12 amps is only 1440 watts. The generator is fine as I just used it for nearly a week following Hurricane Ida. It seems to run fine at home as long as I used my heavy duty extension cord. I looked at the capacitor and it doesn't have any bulges. Should I replace it anyway? Or any other ideas of what the issue might be?

I ran a small job smart compressor on a 3500 watt champion gen. Running amps was somewhere around 4-5 range. Would stall the generator as soon as it Tried to start. Fortunately for me the governor linkage was easy to access and we were able to get a little more effort out of the generator to get the compressor started.

The way it was explained to me was that 3500 was the rating for the whole unit...that is to say half went to the 240v plug so 1750 for the 120’s half to each circuit gave me 825 watts on each 120v plug or 6.8 amps. I’m sure start up was way over that...

some Inverters are rated the same way but that’s a headache for another day.

That's not really the way it works, assuming it's actually a 240volt unit (which as far as I'm aware Champion doesn't make a 240 unit this small) you would still have at least 1750 watts available at the plug, but in reality its likely a 120volt only generator and all 3500 watts is available for the compressor, you stalling the generator furthers my belief in this, pulling only 1750 watts would not stall the engine.

Motors of all types (unless equipped with a VFD or soft start function) have an extremely large inrush current on startup for a second or two, usually in the range of 7-10 times the running amps, which is not an issue when connected to the seemingly limitless energy of the grid, but it is an issue when connected to a small generator with limited capacity. Your compressor could have been pulling 6000watts or more at startup, which would very quickly slow the rotation of the generator and engine, and in your case slowed at such a rate that the engine governor could react quick enough and when it did react the engine did not have enough power to overcome the load from the generator. By pulling on the governor linkage you likely oversped the engine giving it more inertia to start the compressor, you would have also been able to apply full power sooner allowing the engine to absorb the surge load placed on the generator from the compressor.

I attached pics showing the specs of the generator, the outlets and the capacitor the splitter uses.

As to the output of the generator it has 5250 running watts and 6500 surge. When you engage the splitter you hear the generator surge and the splitter motor either tries to spin but only goes a little or it spins up and works fine throughout the split. It doesn’t have a problem running after it gets going, it’s just initial start up.

As mentioned I ordered a new cap to try. Hopefully it’ll arrive before the weekend.

When I said I had tried both outlets I meant both of the standard 120v outlets. I do not have an L14-20 plug with adapter so I haven’t tried that. But I may pick up one to try.

If I make an l14-20 to standard 120 outlet adapter how do you do that so it’s 120?

View attachment 282398 View attachment 282399 View attachment 282400

This is enlightening.

All,

I apologize for the mumble-jumble of quotes here. I tried to organize them to fit my train of thought but I can not figure out how to go to the HTML to do it - all I seem to be able to find is the inserted quotes in non-HTML that doesn't allow me to structure them.

Anywho -

You all are missing something.

The generator the OP has is a rotary generator with a split phase output. That is - it is both 120v and 240v.

What you need to know about this is if you think about the alternator like a transformer - you have a center tap (your Neutral in a 4 conductor split phase circuit - what you have in your house if you look at the service entrance panel). You have 2 legs of 120v that, when the hots are connected in a circuit to neutral, get 120v. When you connect both hot legs in a circuit you get 240v.

The rating on the generator is the output of the entire alternator. Unfortunately, on this model generator - that means at 240v. Not 120v, per se.

In more detail - if you were to load balance the generator and draw power from BOTH legs of 120v then you could, in theory, get the rated output of the generator - but spread across 2 circuits, not one.

The OP's log splitter is demanding more power on one leg of the alternator than it can provide - one leg having 1/2 the rated power (again, the rating is for 240v - so 120v is 1/2 of 240).

There are rotary generators that have switches on them that divert the power between a 240v 4 conductor plug (like the L14-20 on the OP's gen) OR the 120v duplex outlets. What is special about these generators is that they switch the "split phase alternator" so that both halves of the alternator are phased together. When this happens the available amperage doubles on 120v.

Ohms law here - V=IR, P=VI

Where P = Power, in watts.

If your wattage is constant (5250w starting in this case) and you divide the voltage by 2 then for the equation to be true the amperage must double.

Since the OP's generator does not have a switch to select between the 240v L14-20 OR the 120v duplex then there isn't a way already there to phase the halves of the alternator, therefore the available power (wattage - but amperage is the more important number, as already discovered with the draw of the splitter motor) out of any of the 120v outlets is going to be 1/2 that of the generators' rating.

I'll throw out there the disclaimer here that when working on your own stuff you assume the risk with it.

Having said that, it has been mentioned in the thread that the alternator on the OP's generator has been used in a lot of generators. It is possible that the alternator has a split neutral and it makes its way in to generators that do have a voltage selector switch. IF this is the case there will be 2 neutral wires coming off the alternator. One neutral per half. If you have this set up - you can parallel the halves of the generator to get all the power out of the 120v side.

Doing the math here - if the gen is 5250 starting watts - that would be 21.875 amps @ 240v and 43.75 amps @ 120v. Just looking at those numbers I highly doubt the alternator has a split neutral - I can't imagine any generator with a 15 or 20a duplex for 120v being rated much over 20a on 120v.

However, it is worth a shot. If you have a 20a rated outlet then use a 20a breaker, don't over-size the breaker. For a running load under 20a it should hold on to a starting load higher than that (breakers are delayed - they can trip by heat or short circuiting - the higher amperage you draw over their rating the quicker they trip).

One last comment on the phasing of the alternator - the way you could do it (in theory - not sure if it is actually a split neutral or not) is one of the neutrals is going to be your hot, and the hot OF THAT HALF is going to be your new neutral. This is why you need a split neutral.

If you have a single wire neutral then there is no way to take the neutral of one half and turn it in to a hot. The alternator windings can't just be tapped in the middle with 1 lead, the alternator winding has to physically be 2 non-connected halves. You can always bond neutral of the halves to joint them externally to the alternator, but if they are connected inside you're hosed. I am not sure you could open up the alternator and disconnect them, but might be worth a shot if you aren't concerned with possibly messing it up to the point of it not going back together. Motors and alternators can usually be rebuilt so there is a good chance it would be possible.

Here is an example of a voltage selector switch. This is my old 2600w rotary.


20210608_143034.jpg


The mess of wires behind the panel is the circuitry. Looking at it is hard to make much sense of it, however the square on the bottom left is a rectifier. That is where the DC output gets its power from. Once you take those wires out - above it are the terminals and wires behind the voltage selector switch. Those wires come from the alternator (4 of them - 2 "hots" [end taps] and 2 "neutrals" [center taps]). The other wires go from the switch terminals to the breaker and all the outlets. If you follow the wires from the outlets and label them you get down to the alternator taps real quick ;)

20210608_144602.jpg



Cheers!
 
Last edited:

Supersurvey

Burning Hunk
Jan 25, 2015
234
New Jersey
Would a larger generator still have the same issues you describe?
 

rodneygt

Member
Jan 18, 2013
27
Thanks for the info FlyFish'n.

Supersurvey, I've seen videos on youtube of people running a similar spitter off of a generator but I think it was an 8000 watt generator.


By the way, after doing the things suggested and replacing the spliters cap, the splitter works better on the generator but it still sometimes won't start and is a little weaker than when on household current.
 

FlyFish'n

New Member
Oct 23, 2021
62
OH
Would a larger generator still have the same issues you describe?
Depends on who you are asking the question to in response to what issue.

All rotary alternator generators that provide 240v (some are 120v only - those dont meet tje following) are "split phase" alternators.

The question is whether there are 2 separate generator coils or if there is 1 center tapped.

As for generator capacity you need to figure out Amperage you need, not Wattage.

Split phase alternators are limited to Amperage across the whole alternator. If you have a 6kw gen, for example, it will allow 25 amps through the alternator.

25 amps at 240v is 6kw.
25 amps on either phase of 120 is 3kw.

If you could phase two separate halves of the alternator together you could stack the 2x 25 amp 120v circuits and get 50 amps. But I dont know of any commercially made alternators over about 4kw that are split in half.... The reason is a 30a twist lock outlet is the biggest you will typically see for 120v - RVs and boats use these. 30a at 120v is 3600w.

So figure out what the amperage is that you need and figure out if one half of a generator, if rotary, can handle it. If you need 25 amps you need a 6kw gen. If you need 18 amps you need a 4320w gen.

If you have an RV with 50a panel and you want to supply an honest 50a to it... RV panels are 120v only, not split phase. So you need a 12kw gen.

Again, once you get over about 3.5kw you wont see 120v only mode on a rotary gen.

There are inverter gens up to about 4.5kw that are 120v-only. Duromax makea a nice one that is multi-fuel (gasoline, propane, natural gas I believe).

Otherwise, if you go rotary and need the amps at 120v you are going to be drawing that on 1/2 of the alternator so the sticker wattage is going to have to double to get you the amps you need.