Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #11   Report Post  
Old September 6th 04, 02:56 PM
James
 
Posts: n/a
Default

The problem Is VERY LIKELY to be a combination of a worn drive plate
(between flywheel and generator drive shaft) and the resonance factor
mentioned here.


"BruceM" wrote in message
...
I would think that it is just simply a resonance factor.
Ever heard one of those old Cummins 160's?
Let them idle & they are as quiet & smooth as a church mouse. Increase the
revs very slowly & you'll find that at 1400, 1600, 1800 & 2000 revs they
just about shake out of the chasis. (truck)
Most diesels do it to a certain extent. Next time it does it, try

adjusting
your governer up or down a few revs & see how it goes.
My guess is that under that certain load, it hits the "rattle" speed.
Maybe if you can tweak it a weeny bit, it might not come down to that

rattle
speed under load?
BruceM


"Wayne.B" wrote in message
...
On Sun, 5 Sep 2004 09:49:03 +0200, "Steve Lusardi"
wrote:
My guess is that it is not electrical. I think your flex plate drive is
either loose or worn out. The alternator has bearings only on the

outboard
end. The engine rear main bearing acts as the other armature bearing.

This
mechanical connection is usually done through a flex plate which is

bolted
to the engine flywheel and a splined hub drives the armature or rotor.

To
check this, the alternator must be removed from the engine.


===============================================

Thanks, your assessment of not being electrical jibes with my
observations. What would explain the intermittent nature of the
vibration given a more or less constant electrical load? Is the flex
plate a coupling with a rubber hub?






  #12   Report Post  
Old September 6th 04, 03:51 PM
Wayne.B
 
Posts: n/a
Default

On Mon, 6 Sep 2004 21:44:37 +0930, "BruceM"
wrote:
I would think that it is just simply a resonance factor.
Ever heard one of those old Cummins 160's?
Let them idle & they are as quiet & smooth as a church mouse. Increase the
revs very slowly & you'll find that at 1400, 1600, 1800 & 2000 revs they
just about shake out of the chasis. (truck)


=========================================

The vibration in this case is way beyond anything normal, and the
generator is designed to run at a steady 1800 RPM regardless of load.

  #13   Report Post  
Old September 6th 04, 03:54 PM
Wayne.B
 
Posts: n/a
Default

On Mon, 6 Sep 2004 13:56:38 +0000 (UTC), "James"
wrote:
The problem Is VERY LIKELY to be a combination of a worn drive plate
(between flywheel and generator drive shaft) and the resonance factor
mentioned here.


============================

Thanks. Any idea how much work is involved in replacing the drive
plate?

  #14   Report Post  
Old September 6th 04, 08:00 PM
Steve Lusardi
 
Posts: n/a
Default

Wayne,
There are many different types.Some are rubber some are spring dampened,
like clutch plates. Others are just a splined hub with spring steel wings
that bolt at a large bolt circle. It is easy to disconnect the generator
from the engine, if it no longer is in the boat. The difficulty in the boat
is limited to the ease of access. On a shop floor, 15 minutes has the engine
and generator separated.
Steve

"Wayne.B" wrote in message
...
On Sun, 5 Sep 2004 09:49:03 +0200, "Steve Lusardi"
wrote:
My guess is that it is not electrical. I think your flex plate drive is
either loose or worn out. The alternator has bearings only on the outboard
end. The engine rear main bearing acts as the other armature bearing. This
mechanical connection is usually done through a flex plate which is bolted
to the engine flywheel and a splined hub drives the armature or rotor. To
check this, the alternator must be removed from the engine.


===============================================

Thanks, your assessment of not being electrical jibes with my
observations. What would explain the intermittent nature of the
vibration given a more or less constant electrical load? Is the flex
plate a coupling with a rubber hub?



  #15   Report Post  
Old September 7th 04, 12:50 AM
Wayne.B
 
Posts: n/a
Default

On Mon, 6 Sep 2004 21:00:43 +0200, "Steve Lusardi"
wrote:

On a shop floor, 15 minutes has the engine
and generator separated.


Thanks, mine is in a fairly accessible location.



  #16   Report Post  
Old November 12th 04, 07:57 PM
Terry King
 
Posts: n/a
Default

I'd try to divide some possibilities, hoping to conquer:

-- Determine if it's a loading or engine malfunction thing by very
carefully marking the governed throttle/injection pump actuator position
under 'normal' operation. If this suddenly moves under the fault
condition, the engine is getting more fuel then. If it doesn't then it's
not load or engine power related, and it's a looseness / shifting
mechanical thing. Maybe coupling, or worse, a loose flywheel.

-- IF it's an 'increased load' thing, two possibilities: (1) Sudden
added load as mentioned by others. Is There an ammeter on this rig??
(2) Sudden intermittent engine malfunction on one cylinder. Sticking
valve? Sticking Injector?

I'd bet on #2 as it would cause strong vibration due to uneven firing.

Keep eliminating 1/2 the possibilities and you'll find it....

--
Regards, Terry King ...On the Mediterranean in Carthage

  #17   Report Post  
Old October 14th 10, 04:45 AM
Junior Member
 
First recorded activity by BoatBanter: Oct 2010
Location: shenzhen China
Posts: 4
Send a message via MSN to placido Send a message via Skype™ to placido
Smile

Quote:
Originally Posted by BruceM View Post
I would think that it is just simply a resonance factor.
Ever heard one of those old Cummins 160's?
Let them idle & they are as quiet & smooth as a church mouse. Increase the
revs very slowly & you'll find that at 1400, 1600, 1800 & 2000 revs they
just about shake out of the chasis. (truck)
Most diesels do it to a certain extent. Next time it does it, try adjusting
your governer up or down a few revs & see how it goes.
My guess is that under that certain load, it hits the "rattle" speed.
Maybe if you can tweak it a weeny bit, it might not come down to that rattle
speed under load?
BruceM


"Wayne.B" wrote in message
...
On Sun, 5 Sep 2004 09:49:03 +0200, "Steve Lusardi"
wrote:
My guess is that it is not electrical. I think your flex plate drive is
either loose or worn out. The alternator has bearings only on the

outboard
end. The engine rear main bearing acts as the other armature bearing.

This
mechanical connection is usually done through a flex plate which is

bolted
to the engine flywheel and a splined hub drives the armature or rotor. To
check this, the alternator must be removed from the engine.


===============================================

Thanks, your assessment of not being electrical jibes with my
observations. What would explain the intermittent nature of the
vibration given a more or less constant electrical load? Is the flex
plate a coupling with a rubber hub?
hello friends, if you want to replace your diesel generator, maybe i can help you. welcome to browser our website www.emacsz.com
any items be of your interests, please contact me!
  #18   Report Post  
Old December 21st 10, 07:48 PM
Junior Member
 
First recorded activity by BoatBanter: Dec 2010
Posts: 5
Default

I suspect there are problems where the electric motor starts and pull a very heavy starting current. Try disconnecting Refrigerator, aircons, bilge pump, see if the problem will disappear. Most diesel to do a certain role. Next time you do, try to adjust as up or down a governor and a number of speed to see how things progress.
  #19   Report Post  
Old December 22nd 10, 10:51 AM
Junior Member
 
First recorded activity by BoatBanter: Dec 2010
Posts: 5
Default

The problem Is VERY LIKELY to be a combination of a worn drive plate
(between flywheel and generator drive shaft) and the resonance factor.
  #20   Report Post  
Old January 5th 11, 03:39 AM
Junior Member
 
First recorded activity by BoatBanter: Jan 2011
Posts: 5
Default

I have an 8KW Westerbeke diesel generator (about 12 years old) which has an odd vibration issue at times. This happens most often under moderate to heavy load and lasts for 15 to 20 seconds at a time. The vibration is so violent that the guages are impossible to read and it. So I just want to know what should be about this.


Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is Off
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Diesel Generator Vibration Issue Wayne.B Boat Building 10 November 12th 04 07:57 PM
UK red diesel costs. Ken Baker Cruising 19 June 8th 04 11:36 PM
Old diesel fuel - two questions Al Gunther Cruising 2 May 30th 04 01:15 PM
uk diesel costs Ken Baker Power Boat Racing 0 May 25th 04 02:41 PM
Diesel outboard? Jack Rye Cruising 4 August 28th 03 08:34 PM


All times are GMT +1. The time now is 11:49 PM.

Powered by vBulletin® Copyright ©2000 - 2022, Jelsoft Enterprises Ltd.
Copyright 2004-2022 BoatBanter.com.
The comments are property of their posters.
 

About Us

"It's about Boats"

 

Copyright © 2017