On board generator putting out 155 volts?

[KanzKran]

Originally Posted by fishmaine

Per twin boat above, turning out the idle adjustment screw on the carburetor may decrease the motor RPM which would typically cause a direct decrease in the output voltage level. I adjusted the idle in this manner to reduce the RPMs but there was no change...the generator still produced exactly 155 volts (although turning in the idle screw slightly did increase the voltage a little bit to about 160 volts)

Have you checked output frequency? That unit, according to the specs and manual, is a constant-speed design with the usual two windings for 120/240V output, or connected in parallel for 120V only. Engine speed is mechanically governed at 2571 rpm, with a speed increasing belt drive to a 3600 rpm generator. So if the voltage is way off, it's either a bad or loose neutral (if 120/240V), or the regulator is shot.

[Domo]

Are those Canadian volts? If so, that's about 120 USVAC.

[Domo]

Are those Canadian volts? If so, that's about 120 USVAC.




BTW - the Voltage Regulator is what regulates the voltage (hence the name). The motor RPM is what regulates the power capable of being delivered. That's why you hear the motor rev up to deliver more power when your A/C (or other load) kicks on, however the voltage stay constant (yes, within design tolerance and phase of the moon changes).

[fishmaine]

Hi all....I need to be on the road shortly so to resolve this issue quicker I went in to a local RV tech and he was able to quickly confirm that the voltage regulator on the generator was bad....his meter was reading $155 volts also. He also confirmed that our automatic transfer switch (ATS) was defective by connecting the shore power lines to the generator input site on the ATS and running 120 shore power through the generator side of the ATS...again no power in the RV. This confirmed that the ATS was not switching and damaged inside somehow...possibly by high voltage from the generator or maybe from the fact that the ATS had a slowly developing manufacturers defect (it was recalled several years ago - I have the IOTA 50-ITS 50R). The end result is that I will be buying and installing both a new Generac voltage regulator and a new automatic transfer switch. I am planning on getting the ESCO LPT50BRD ATS which is the historically recommended replacement for the IOTA. Both the voltage regulator and ATS are available on Amazon.....VR is $119, ESCO ATS is $177. Thanks once again for all your valuable help. The tests I conducted per your input gave me the knowledge to proceed with the repairs!

[twinboat]

Originally Posted by Domo

Are those Canadian volts? If so, that's about 120 USVAC.




BTW - the Voltage Regulator is what regulates the voltage (hence the name). The motor RPM is what regulates the power capable of being delivered. That's why you hear the motor rev up to deliver more power when your A/C (or other load) kicks on, however the voltage stay constant (yes, within design tolerance and phase of the moon changes).

Wrong.
Most gasoline powered RV generators are constant speed units. What you hear is the load increasing, not the RPMs.

Portable, inverter type generators varry engine speed depending on load.

Check out the specs below for a very popular Cummins-Onan 4000 watt RV generator.

It turns at 3600 RPMs for 60 Hertz.
It turns at 3000 RPMs for 50 Hertz.

If the generator speed changed up and down the HZs would be all over the place.

Check it out.

[Domo]

Originally Posted by twinboat

Wrong.
Most gasoline powered RV generators are constant speed units. What you hear is the load increasing, not the RPMs.

Portable, inverter type generators varry engine speed depending on load.

Check out the specs below for a very popular Cummins-Onan 4000 watt RV generator.

It turns at 3600 RPMs for 60 Hertz.
It turns at 3000 RPMs for 50 Hertz.

If the generator speed changed up and down the HZs would be all over the place.

Check it out.Attachment 232786

Well, thanks for the update!

[KanzKran]

Originally Posted by twinboat

Wrong.
Most gasoline powered RV generators are constant speed units. What you hear is the load increasing, not the RPMs.

Portable, inverter type generators varry engine speed depending on load.

Check out the specs below for a very popular Cummins-Onan 4000 watt RV generator.

It turns at 3600 RPMs for 60 Hertz.
It turns at 3000 RPMs for 50 Hertz.

If the generator speed changed up and down the HZs would be all over the place.

Check it out.Attachment 232786

What he said about frequency.

Same as induction motors, frequency times 120 divided by number of poles is generator speed (60Hz x 120 / 2 = 3600 rpm). Most small generators are 2-pole, so they spin at 3600 rpm for 60Hz output (3000 rpm for 50Hz). Larger diesels are usually 4-pole, so they spin at 1800 rpm, and really large ones may be 6- or 8-pole and turn proportionately slower. Power plants at hydrodams have as many as 64 poles which would require 112.5 rpm to generate at 60Hz.

[twinboat]

There are some RV generators sets that belt drive the generator end.
Doing that, they can slow the engine RPMs down for less noise, but still turn the head at 3600 RPMs for 60 HZs. Very common in the gas, 2 cylinder, vertical engine models.

[lwmcguire]

Onan QD 8000 is a variable speed

Are there any inverter gas or propane generators in rvs?

[twinboat]

Originally Posted by lwmcguire

Onan QD 8000 is a variable speed

Are there any inverter gas or propane generators in rvs?

We haven't seen fuel injected, gas generators in RVs yet. Carburators died in the early 80s.

Inverter generators of that size don't seem to be out there yet, although Honda has a eu7000 portable now.

[Trickdog]

I have the same model. You need to check HZ first before trying to adjust the voltage regulator according to the manual. You should be reading around 60HZ with the generator loaded if possible. You can get a decent meter on Amazon that will read HZ. Then there is a small adjustment screw on the voltage regulator. Mine would not adjust and had to buy a new one. Was around $200 if I remember correctly. I will see if I can find the manual and send it to you (PDF).

[Trickdog]

Originally Posted by Trickdog

I have the same model. You need to check HZ first before trying to adjust the voltage regulator according to the manual. You should be reading around 60HZ with the generator loaded if possible. You can get a decent meter on Amazon that will read HZ. Then there is a small adjustment screw on the voltage regulator. Mine would not adjust and had to buy a new one. Was around $200 if I remember correctly. I will see if I can find the manual and send it to you (PDF).

I PM'ed you with my email address. I can send you the service manual not the owners manual for your generator model. Handy to have.

[153stars]

Just in case someone is searching later with bad neutral. That will read high one leg low other, but still 240v across hot legs,
like 100v + 140v or 80v + 160v ect. = 240v