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 > 170VAC coming from my Onan generator

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SHRED

Encinitas, California

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Posted: 02/19/21 09:15am Link  |  Quote  |  Print  |  Notify Moderator

It's a 1995 4000 BGE.

I posted earlier but wanted to focus in on this problem.

I tested the lead coming into the breaker switch and it was a consistent 170 VAC.

What should I check next and how?
Regulator?

Thanks


1995 Lazy Daze 23.5' TK

Gjac

Milford, CT

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Posted: 02/19/21 09:19am Link  |  Quote  |  Print  |  Notify Moderator

Does your genset seem like it is running at a higher rpm than normal? You can buy cheap HZ meter plug it into your 120 v socket and adjust the speed to read the correct HZ at the proper rpm.

enblethen

Moses Lake, WA

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Posted: 02/19/21 09:19am Link  |  Quote  |  Print  |  Notify Moderator

Governor! Does the genset sound like it is running overly fast?
If you can see and get to the throttle linkage see if it is moving.


Bud
USAF Retired
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2003 Chev Ice Road Tracker


Dusty R

Charlotte Michigan 48813

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Posted: 02/19/21 11:22am Link  |  Quote  |  Print  |  Notify Moderator

Gjac wrote:

Does your genset seem like it is running at a higher rpm than normal? You can buy cheap HZ meter plug it into your 120 v socket and adjust the speed to read the correct HZ at the proper rpm.


Look and see what the output voltage is supposed to be. At that voltage it is also running at 60 HZ, this has to do with the building of the generator.

So using a decent volt meter will do.

If there is an adjustment on the governor I would try slowing the engine down while watching the output voltage, setting it at or a whisker over.

Jetstreamer

Milwaukee, Wisconsin

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Posted: 02/19/21 11:35am Link  |  Quote  |  Print  |  Notify Moderator

Check the batteries and verify your meter is reading correctly by checking voltage from home source.
Just saying cause I had this happen to me once.

MEXICOWANDERER

las peƱas, michoacan, mexico

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Posted: 02/19/21 12:15pm Link  |  Quote  |  Print  |  Notify Moderator

You need to seek and record the MODEL and the SERIAL NUMBER of your generator then post it. Some generators are volts per Hertz (speed sensitive)

And DO NOT TRUST a critical finding like this to a single measuring instrument.

SHRED

Encinitas, California

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Posted: 02/19/21 12:28pm Link  |  Quote  |  Print  |  Notify Moderator

MEXICOWANDERER wrote:

You need to seek and record the MODEL and the SERIAL NUMBER of your generator then post it. Some generators are volts per Hertz (speed sensitive)

And DO NOT TRUST a critical finding like this to a single measuring instrument.


MODEL: 4BGEFA26100M

SERIAL: D953355775

dougrainer

Carrolton, Texas

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Posted: 02/19/21 12:29pm Link  |  Quote  |  Print  |  Notify Moderator

AC Output
Voltage Too Low
Or Too High
Noisy Generator
Possible Cause
1. Open circuit breaker
2. Open circuit between brush
block an CR4 rectifier
3. Brushes stuck in holder or
not making good contact with
slip rings
4. Defective CR4 bridge
rectifier
5. Open, grounded, or short
circuit in rotor, stator, or
transformer
1. Engine governor incorrectly
adjusted
'2. Open diode in CR4 bridge
rectifier
*3. Brushes worn or not making
good contact with slip
rings
4. If generator frequency is
within specified limits but
voltage is incorrect,
transformer is incorrectly
connected or defective.
'5. Open, grounded, or short
circuit in rotor, stator,
or transformer
'causes low AC output voltage
1. Loose brush holder
2. Worn generator end bearing
3. Rotor and stator rubbing
together due to: a) varnish
lumps, orb) rotor
misaligned with crankshaft
Corrective Action
1. Locate cause of overload
and correct as required.
Reset breaker
2. Check for continuity and
correct if circuit is open
3. Release brushes if jammed
in holder. Clean slip
rings if dirty.
4. Test rectifier and replace
if defective
5. Test each component for
open, grounded, or shorted
windings and replace if
defective.
1.
2.
3.
$.
5.
Refer to Governor
section
Test CR4 rectifier and
replace if defective
Check length of brushes
and replace if worn
excessively. Clean or
replace slip rings.
Adjust tap connections on
transformer secondary
windings to obtain correct
voltage. Replace
transformer if voltage cannot
be corrected with adjustments.
Test each component for
open, grounded, or shorted
windings and replace if
defective.

SHRED

Encinitas, California

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Posted: 02/19/21 03:00pm Link  |  Quote  |  Print  |  Notify Moderator

dougrainer wrote:

AC Output
Voltage Too Low
Or Too High
Noisy Generator
Possible Cause
1. Open circuit breaker
2. Open circuit between brush
block an CR4 rectifier
3. Brushes stuck in holder or
not making good contact with
slip rings
4. Defective CR4 bridge
rectifier
5. Open, grounded, or short
circuit in rotor, stator, or
transformer
1. Engine governor incorrectly
adjusted
'2. Open diode in CR4 bridge
rectifier
*3. Brushes worn or not making
good contact with slip
rings
4. If generator frequency is
within specified limits but
voltage is incorrect,
transformer is incorrectly
connected or defective.
'5. Open, grounded, or short
circuit in rotor, stator,
or transformer
'causes low AC output voltage
1. Loose brush holder
2. Worn generator end bearing
3. Rotor and stator rubbing
together due to: a) varnish
lumps, orb) rotor
misaligned with crankshaft
Corrective Action
1. Locate cause of overload
and correct as required.
Reset breaker
2. Check for continuity and
correct if circuit is open
3. Release brushes if jammed
in holder. Clean slip
rings if dirty.
4. Test rectifier and replace
if defective
5. Test each component for
open, grounded, or shorted
windings and replace if
defective.
1.
2.
3.
$.
5.
Refer to Governor
section
Test CR4 rectifier and
replace if defective
Check length of brushes
and replace if worn
excessively. Clean or
replace slip rings.
Adjust tap connections on
transformer secondary
windings to obtain correct
voltage. Replace
transformer if voltage cannot
be corrected with adjustments.
Test each component for
open, grounded, or shorted
windings and replace if
defective.


I didn't see "regulator" in there.

I'm getting to the point where professionals need to look at this mess I think.

I did unhook the ATSwitch and the breaker on the genset didn't trip off which was my original symptom.
Now I'm thinking the high voltage may have damaged the ATS.

* This post was edited 02/19/21 03:52pm by SHRED *

time2roll

Southern California

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Posted: 02/19/21 03:41pm Link  |  Quote  |  Print  |  Notify Moderator

SHRED wrote:

I didn't see "regulator" in there.


Might interchange the word governor since it regulates engine speed.

1. Engine governor incorrectly
adjusted


Yes get it in to a pro for best results.


2001 F150 SuperCrew
2006 Keystone Springdale 249FWBHLS
675w Solar pictures back up

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