Only 60V from generator

ramloui

Hello all!
I hava a small generator (Hyundai HDD3500) that is only putting out about 55v per leg. I changed the AVR to no avail. I would really like to get it fixed because it is the only generator this size that can provide 240V which I can hook up to a Magnum PAE4024.

Thanks for your help!
Louis R.

BB.

Louis... Is this the genset?

https://www.amazon.com/Hyundai-HHD3500-3500-Watt-Portable-Generator/dp/B004647M2A

If so, then it has a 120 and a 120/240 VAC switch setting... Switch set correctly?

You are using the 120/240 13 amp twist lock receptical?

Are you measuring the "240 VAC" in the correct location? Twist lock:

http://www.generatorsforhomeuse.us/l14-30/




If you are measuring Y to X -- You should see your 240 VAC.

If the switch is in 120 VAC only, and you measure from Y to Neutral, or from X to Neutral, then you will (my guess) measure around 55-60 VAC (if it has a floating neutral).

If all is correctly setup and measured, then you may want to disassemble the electrical panel and look for loose/dirty/corroded connections.

-Bill

ramloui

Thanks for the response Bill!
Yup, that is the generator. The switch is indeed positioned toward the 240v side and I get the low voltage on either of the two (normally) 120V leg of the 240v outlet.

I had used the gen a few weeks earlier, no issues. Next time I took it out during a power failure at my home, connected to the manual transfer switch, the lights were dim, then bright for a few seconds, then dim again, and so on. My electronic devices were switching on and off on their own! I stopped everything. 

I did some research on the web, all I found was related to “no power” problems. AVR is inexpensive, so I thought I would replace it and see, but nope. Same issue.

One video suggested resistance measurements at different points and all readings seemed normal.

I ended up buying a new generator but the smallest I could find with 240V capability is 8000W (not a problem), but is far from portable at about 150# (that is a problem). Which is why I would really like to revive the 3500W gen.

Chers!
Louis R.

BB.

That you are seeing 1/2 the voltage sounds more like the 120/240 VAC switch is not working correctly...

I think there are two coils in the alternator... Put them in parallel and you get 120 VAC. Put them in series you get 240 VAC (and still get 120 from neutral to L1 or L2).

I guess it is still possible that the AVR is bad...

Wiring diagram (page 49 of file):

https://www.manualslib.com/manual/628654/Hyundai-Hhd3500.html?page=49#manual

Do you see 120 or 60 VAC on the 120 VAC outlet?

-Bill

ramloui

I did some more checking just now. At the 120V outlet, I get 57V at both top and bottom connections. On the 120/240V outlet, I get 120V across the 240V pins, and 57V between the hot and neutral (or ground) on both legs. I opened up the alternator cover and still measured 57V at each of the power terminals. I also measured 10.7VDC at the brushes if that means anything.

Cheers! 

Louis R.

BB.

A pretty nice generic debugging video:

https://www.youtube.com/watch?v=O_yy1SrAljQ

-Bill

NANOcontrol

It sounds like the generator is working with residual magnetism. Did you try it with a resistive load line a heater?  Did you check the brushes? A friend of mine is a contractor with many generators and these brushes wear out. And worse than that the plastic deforms from heat and they stick. They are really cheap and don't last long.  I've worked on diesel light tower generators and had to reflash the armature to get the magnetic field back.

RCinFLA

That generator has a 120vac only switch.  This allows you to get full generator power on 120vac only.  They use the 240vac socket outlets because it handles the greater current when run as 120vac only mode.

Make sure you did not accidentally put it is 120vac mode.