HF Predator mod to parallel

[DPGBG]

Hello all. First time posting and impressed with the help on this forum.

I'm trying to re-wire a HF generator to parallel. I have tried many things I found on this site as well as others and I just cant seem to get it to work. I have the wiring diagram but not sure how to get it on this forum. If anyone can help I can e-mail it to you.

What I have tried was to switch the wires as explained in the 3000W Chinese Gensets Info. topic on this site. I do that and I get 20 volts across the two outputs. I also read that if you get 0 to 50ish volts to switch a set of leads. I didn't try this and I'm not 100% clear on which two leads to switch??

To try and explain without the diagram, I have 4 wires coming out of gen head. Coil 1 has Red and White. Coil 2 has white and black. Red and black are power and whites are neutrals. Coil 2 is the only coil that the AVR monitors.

So at the terminal block, I take coil 1 red and coil 2 white and put them together, and coil 2 black and coil 1 white and put them together. When metering across the two I get 20 volts.

I have been testing at the terminal block figuring if I can get it to 120 volts there then I will worry about the rest of the plugs and things down stream.

Any help would be greatly appreciated.
Thanks all..

[MEXICOWANDERER]

The SOLE way to utilize 180 degree opposed phases in a 4-wire generator (240 volt) is to use a transformer. 98% efficiency. Changing 3 phase to single phase 240 volts by using a Scott connection (equal 3 phase loading).

Apparently SOME HF generators are reconnectable. 240 to 120. Some ONAN generators came from the factory connected for 65 amperes @ 120vac. My expensive 5500 Yamaha diesel genset was not reconnectable.

Make certain what ever you buy is compatible with your model number and serial number HF generator. If it isn't it's transformer time.

Hint: Many higher powered generators use a PRIMARY exciter to initiate SECONDARY exciter voltage via a dedicated rotor and stator. The seondary exciter amplifies this into the big field winding within the big rotor and the product is dispensed via the secondary stator.

[MrWizard]

Explanation of problem

OEM configuration the AVR senses/sees 20vac ,
When the winding are phased parallel the AVR senses 100vac
AVR reduces from field voltage until it senses 20vac on the sense wires
Which makes the output approximately 24vac

Need 20vac for the AVR sense input to get 120vac on the phased output

[MrWizard]

He just came back to it
And resurrected it
When i saw it, i first thought new poster trying to do the same thing
then after posting and taking a second look
I realized
It is the OP coming back to his project

[Gdetrailer]

MrWizard wrote:
Just re read the earlier 2015 posts from DRPG And my self

THE parallel b wiring mod in my drawing is correct , it's all about where the avr gets its reference voltage

Suggestion, if it doesn't work
Put it back to stock, sell it, and buy a newer version replacement generator

I suspect that you are correct on where the AVR gets it's reference voltage. Good chance OP reversed the phasing on the AVR windings when paralleling.

In this case, the best way to figure out is to use a Oscope to make sure all windings are in the same phase (good chance wiring colors may be reversed from diagram)..

Most gens have only one AVR tap but your diagram shows 2 so one would have to select the correct AVR winding in the correct phase to make that work..

But, I believe the OP has long abandoned this thread and this project..

[MrWizard]

Just re read the earlier 2015 posts from DRPG And my self

THE parallel b wiring mod in my drawing is correct , it's all about where the avr gets its reference voltage

Suggestion, if it doesn't work
Put it back to stock, sell it, and buy a newer version replacement generator

[MrWizard]

If you search the Chinese 3000w generator thread
There is modification drawing and info for paralleling the windings
As MFG it is 240v center tapped for (2) 120 legs
The rewire is Not red with black, and the two whites
The the rewire mod is red wire connected with the white wire from the black leg,
And black wire connected with white wire from red leg
This puts the two windings in phase parallel,

(You need to think of this as two feeds laid out side by side, 1,2-3,4 You are going to pick up 3&4 and place them on top of 1&2, 3 goes on 1, 4 goes on 2)

The fact that 2 wires are white, mean nothing to the phasing mod, they are colored what they are for the workers , to make assembly easier and faster,

If MFG here in the states they would all be the same color and numbered

Either pair can be used as the hot and the other pair for neutral,
Then
You must correct the wiring down steam going from terminal block to the circuit breaker and outlet's because OEM wiring will now have hot and neutrals crossed connected, and a circuit breaker in the neutral circuit instead of the hot side,
get a new 25 amp breaker for the hot leg, run your new hot to 25a breaker then from breaker to the rwist lock outlet hot connection,
Run the new neutral to twist lock outlet neutral,

If you want to use the duplex outlets
Run hot wire from terminal block to 15amp breaker then to the duplex outlet,
New neutral to duplex outlet

There was a picture of this mod, some where in the 3000w thread, but it might not be there any more although the wiring instructions text is still there,

Hope this helps , should get you what you want to do
And when done correctly works perfectly, the avr now keeps even better voltage control

[Gdetrailer]

Long live the "zombie" thread back from the dead.. Well I guess it is pretty close to Halloween and perhaps need to play "Thriller" by Micheal Jackson to set the mood..

Last post was back in 2015, OP GAVE UP on this project.

And Seon, your "device" cannot and will not and will never work for what the OP was trying to do which was to REWIRE A OLD SCHOOL NON INVERTER GEN! The gen in question is a Harbor Freight 4kw 240/120V gen.. OP was trying to parallel the 120V windings to make it a 120V only gen..

OP was not able to make it work, I suspect the issue was coming from how the AVR was getting it's feedback voltage from the windings and it did not like it..

The device you posted is designed to connect two INVERTER GENS together, a feat which isn't so simple with old school non inverter gens.

[Seon]

DPGBG wrote:


I'm trying to re-wire a HF generator to parallel.

Parallel the Genny head windings, 120v only but more amps, same Watts

I didn't read all the replies but would this help?

https://www.harborfreight.com/rv-ready-30a-parallel-kit-for-predator-2000-inverter-generator-62564.h...

[Tom_M1]

You seemed to have missed the fact that the OP has only one generator. I don't understand why you are telling us about syncing two generators. The link to the YouTube video just before your message explained exactly what the OP was trying to do, why his approach did not work, and what was needed to make it work.

Here's the link again:
https://www.youtube.com/watch?v=zSpkvS3ha1Q

Here's a screen capture from the YouTube video:

[MEXICOWANDERER]

The sole way to utilize 180 degree opposed phases in a 4-wire generator (240 volt) is to use a transformer. 98% efficiency. Changing 3 phase to single phase 240 volts by using a Scott connection (equal 3 phase loading).

Isosynchronization 2 generators requires patience and 2 equal generators and two equal prime movers. Meaning load sharing. Inverter generators utilize 100% electronics to analyze unit loading by MEASURING PRIMARY FIELD CURRENT difference between the two generators of which both generators must be inverter units.

AMPLIFICATION
Balanced phase loading is easy with a transformer, insanely complicated to try and do it electronically.

A Hollywierd commercial maker wanted me to parallel a pair of 20 Kw mobile gensets of different manufacture. Freq droop between the 2 was 4 Hz at a 13 Kw load. No way Jose. The lead lag would produce 101% load on A with B 75% load.

The 3rd governor did the trick on the Ms. Kelley II to establish a paralleling station between the 2 40 Kw gen sets.

For single generator 4-wire output 240 volt generators use a transformer. For older 12 wire reconnectable generators like the Onan 6.5 NH units, follow rewire instrucions off the plate.

What did I miss?

[Tom_M1]

MEXICOWANDERER wrote:
You need to fully develop "load sharing" before thinking about frequency synchronization. If your true inverter prime mover senses frequncy inbalance, it shuts down. Good luck with that. If the HF had a truely accurate governor then you might have a chance with a paralelling system. The results do not match the cost of time and materials.

You missed the point. The OP has one generator and is trying to parallel the two 120 volt windings and increase the current output.

[MEXICOWANDERER]

You need to fully develop "load sharing" before thinking about frequency synchronization. If your true inverter prime mover senses frequncy inbalance, it shuts down. Good luck with that. If the HF had a truely accurate governor then you might have a chance with a paralelling system. The results do not match the cost of time and materials.

[Starcraft21SSO]

DPGBG wrote:

What I have tried was to switch the wires as explained in the 3000W Chinese Gensets Info. topic on this site. I do that and I get 20 volts across the two outputs. I also read that if you get 0 to 50ish volts to switch a set of leads. I didn't try this and I'm not 100% clear on which two leads to switch??

The AVR is holding the voltage down. What is happening is explained here:

https://www.youtube.com/watch?v=zSpkvS3ha1Q

[Gdetrailer]

cbeam2 wrote:
What about a parallel harness like they do with the Honda generators?

The only consumer gens which are designed to be paralleled are inverter types which A Honda 2000i is.

The gen the OP is dealing with is an old school non inverter gen.

This gen is designed to be able to supply 240V and 120V, The full wattage only available via the 240V connection..

The 120V connections only give you half the wattage.

This is due to the gen having a winding which is 240V and there is a center tap. The 120V is derived due to the center tap.

The problem the OP is having is they want ALL the wattage on one 120V output.

The only way to do this is to separate the windings of the gen head at the center tap.

Only then can the two 120V windings can be paralleled.

The problem is that the way the AVR is wired may be causing an issue since the AVR is sampling a small voltage from one of the windings..

This can be done in most cases but it is not easy or for the faint of heart.