Harbor Freight Gen Head

[DRJensen]

HF has a 10kw/7.2kw gen head on sale right now, does anyone have any experience with these? Are they any good or comparable to an ST head? I am under the impression that an ST head is for continuous use for years  and these HF and other heads you see might be for backup only and will play out if used for extended periods. Northern tool has one also and it looks better just from the pictures but it is right at $900 for it as the HF one is $299.99!!!

[Tom Reed]

That's a 2 pole 3600 rpm head. I have not heard good things about them.

[DRJensen]

 ,,, thats what I was a fraid of. Golden rules is you normally get what you pay for. Thanks for the reply.

[mr.fixit]

I have one and works good.It came with the rear plastic cover broken from shipping so I called them and they are sending that and the capacitor out no charge.
I will let you know if they come.

As far as working,I have used it approx. 2 -3 hrs. and so far so good.It's connected to my Xantrex 6048 inverter and the inverter syncs up fine with it.
The previous head I had was a Mc-allte 5000 watt and had issues with low voltage until I replaced the capacitor,then it was ok.But the inverter would spit it off when a heavy load first came online.

I paid $500 for the McAlte so could almost buy 2 of the HF heads.

If you do get the HF head,check the wire connections under the end cover.Mine had a plastic 4 wire connector with 1 wire not pushed in completely.Come to think of it,the Mc-alte head had a loose wire in it too.Gotta double check everything.

[Henry W]

They are not as bad as some people think. If members or others want to make them more reliable. Replace the capacitor with a higher quality one and have an extra set of diodes on hand. I had one and I looked at it close enough to see that quality was pretty good. the windings and bearings looked good. For the price they can be picked up just buy 1 or 2 spares and members or others will be set.

What kills generator head is dis-reguarding the power factor that the generator head is rated for. The Harbor Freight generator head is rated for 10kw surge and 7.2kw continuous for so many hours. I don't know how many. Mc-Allte rates their lighter 2 pole units the same way. So if members or others want the Harbor Freight Gen Head units to last on a power factor of .8 than limit the Harbor Freight Gen Head to 5000 watts and it should do fine. Motor starting is another factor that is over-looked. Look at the LRA Label (Locked Rotor Amps) LRA is the max amps a locked compressor or motor will draw. it is best to keep below the LRA Rating. So when members or others figure out max load, RLA has to be included when sizing a Generator Head. This is the reason I am going with a 27.5 - 33Kw generator head on my next build.

The Harbor Freight Gen Head should last fine and be more efficent if they are limited to 4000 - 5000 watts anyways. Members and others could double the life (and longer) of many generator heads if they follow what I written.

Hope this helps.

Henry

[Tom Reed]

It is my understanding that the inverter/chargers have a terrible PF. I've read several reports of the HF heads dieing after a few hours of battery charging. Also reports of bearing issues. I am a HF fan and buy lots of toolz from them. My philosophy is if I use a cheap tool enough to break it or wear it out the purchase of a good one is then justified.

[Henry W]

This is why I de-rate generator heads. $500 and $700  brushless Mc-allte generator heads will have the same issues as the cheap Harbor Freight generator heads. They are pretty much designed the same. About bearings. It is not hard to replace the bearings in the Harbor Freight head. Plus higher quality bearings are inexpensive. I know an OEM for Mc-allte, and on projects in the works I will use them because of my cost. But for do it your selfers that want to save dollars the Harbor Freight unit can be updated with better bearings and capacitor and an extra set of spare diodes for around $100.00. That is still much cheaper than a Do it your selfer purchasing a Mc-allte 6.8kw head. As I said before the copper windings on the stators and rotors looked good on the Harbor Freight units. So, it is possible to save at least a couple hundred dollars after the upgrades on a Harbor Freight unit, and have a unit perform just as good or better than a comparable priced Mc-allte unit that is rated at lower watts.

De-rate a Harbor Freight unit and do some proper power management and they will most likely last last as long or better than some 3000 to 5000 watt high dollared units.

Henry

[Henry W]

Now if your thinking of making a 10kw generator than I would look at an ST head. But I would still would de-rate any ST. For 10Kw output I would look at a 15Kw.

I have a Nice ST-10. It is an earlier unit that can be set up for 50 or 60 Hz. it weighs over 320 lbs. It looks like it is built better than the ST-12 I had.

The ST-10 will be de-rated to around 7Kw. I don't expect any problems with it, but you never know. The bearings should be replaced with higher quality bearings down the road.

Henry

[BruceM]

Good points, Henry.  The ST heads often need new diodes, doghouse replacement, and new bearings within the first hundred hours, and they need an AVR, in my opinion. 

If I was starting over I'd give the HF 10KW unit a serious look, for my 2.5 KW application.

[mike90045]

It is my understanding that the inverter/chargers have a terrible PF.

And some have .9 PF on the charger.  My Xantrex XW does.

[Tom Reed]

It is my understanding that the inverter/chargers have a terrible PF.

And some have .9 PF on the charger.  My Xantrex XW does.

Yea, that XW is one of the best.

[Seafarer12]

Power Factor can be corrected if you know if its a leading or lagging power factor. Utility companies use capacitor banks most of the time to correct power factor since most loads are inductive.

[DRJensen]

Ok my ST head would not develop voltage any more, I purchased the Harbor Freight gen head with the 20% coupon online and it was shipped to the house for 275.00. The fan melted the first run so I took that off and also replaced the flimsy plug/gauge panel with a 12x12 carlon pvc box and mount two 4 inch fans forcing air thru the gen head, so far so good. The only concern is that it will not maintain 120 VAC or 240 VAC when loaded @ 3000 watts. It drops to around 110 or 220, I don't think it will hold if I loaded it more. It has a plastic capacitor 45uF 450volt, would a higher quality and/or different value make a difference in output voltage. So far this is the only issue I have with it. It is much quieter and has less vibration than the ST head. It runs hotter than the ST but that is to be expected with it's compact design. I hope someone can advise me on the capacitor as I really don't understand how this brushless unit works . I had a 5500 watt portable unit once that would maintain 240 vac with our electric water heater appling the load. Thanks for looking and have a good day.

[mr.fixit]

I replaced mine with a 40 uf and it maintains voltage better.
Surplus center is where I got mine.
Keep in mind the cap is located such that the cooling fan pulls air across it to keep it cool.

I replaced the plastic end cover on the head with a metal breaker box and left enough space along side for the cap to get all the airflow that the cooling fan draws in.

[buickanddeere]

 As previously stated. Just because the nameplate states 10Kw doesn't mean that 10Kw continuous load is a good idea. I would not continuously loading a discount or consumer grade generator beyond 7.5kw .