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[oldiron]

 A question for those with familiarity of marine steam engines operating on barring (jacking or turning) gear. I'm involved in the preservation of the exCPR vessel SS Keewatin. It contains a 3200 HP quadruple expansion engine Clyde built in 1907.
 As part of the museum experience we have the barring gear rigged to turn over by electric motor to move the main engine for public viewing. We are having some question as to what to expect to realistically see in main engine RPM when operating this way. Initially the museum was hoping for 2 to 3 RPM. However we don't come anywhere close to that and we don't want to damage equipment by over speeding the turning gear. Research seems to say something in the order of 1/10RPM.
  Does anyone have any feel for what to expect?

thanks

John

[derekwarner]

Hullo oldiron....this will be a very interesting thread.........
The barring gear worm wheel [vertical shaft axis] & worm [horizontal shaft axis] is shown below in the bottom RH quadrant if the picture
I assume the geared electric drive is just FWD of the worm shaft
Do the museum authorities understand that to turn a cold engine, steam preheat may have been required together with full lubrication pumping available to all engine components?.....
In an engine such as this, the baring gear would have had a number of uses.....however the principal function would have been to turn an engine for maintenance purposes ie., to gain better access to a shaft journal
Is there any original maintenance documentation for the engine available?.......Derek
 

[oldiron]

Derek

  I'm a licensed steam engineer myself with a substantial amount of experience on reciprocating engines. We have the oiling situation in hand and gone over very thoroughly. Warming the engine would be a benefit, but is not possible as the boilers were removed fourty years ago. The engine turns quite freely as the prop is disconnect from the shaft so we don't have its drag.
  A 35 horsepower motor is attached to the barring gear arrangement and the steam engine has been removed. The electric motor drives through a three belt pulley drive system and works very well. the motor is controlled by a variable speed three phase electronic motor controller.
  All works, however, we are in discussion about the expected speed of the main engine. I feel the main engine RPM is very low (fractional RPM?), however, the museum is looking for more. Since we don't want to damage any equipment that's why I'm trying to get a handle on the expected speed from the steam driven barring gear.
  No there is no engineering paper work available for this vessel.

John

[BarryM]

John,
I envy your task. My steam experience of recips. was confined to their use as auxiliaries and I'm happier with turbines. However, digging out my old copy of 'Sotherns', I found a reference to a turning engine for a 1500 IHP reciprocating engine. This quotes a figure of 1 rev/6.5 minutes, i.e. glacially slow!
I suppose it comes down to whether you are looking for something factually correct or a speed which demonstrates the action of the engine. I have seen a small triple expansion in a museum rotating at about 10 RPM to better explain the valve and piston action.
Regards,
Barry M

[oldiron]

John,
I envy your task. My steam experience of recips. was confined to their use as auxiliaries and I'm happier with turbines. However, digging out my old copy of 'Sotherns', I found a reference to a turning engine for a 1500 IHP reciprocating engine. This quotes a figure of 1 rev/6.5 minutes, i.e. glacially slow!
I suppose it comes down to whether you are looking for something factually correct or a speed which demonstrates the action of the engine. I have seen a small triple expansion in a museum rotating at about 10 RPM to better explain the valve and piston action.
Regards,
Barry M

  Barry

  Thanks, that's very helpful and lines up with what little other info I've found on the subject. Yes, I agree, it is glacially slow. When we first put power to our barring gear one of the lads said its moving. I had to look real close at the crosshead beside me to see any motion. As we increased the motor revs we, of course, so more motion in the engine.
  The whole idea of the exercise is to give the public some idea of what this looks like in motion since, lets face it, the vast majority of people in this day and age have no idea what a steam engine is or how it works (at least in this country). However, in doing this we don't want to damage the barring gear mechanism in the process by over speeding it. After all, it is 1907 technology.

Here's a link to the vessel's web site: http://sskeewatin.com/

John

[oldiron]

For interest, here's a pic of your's truly buried in the valve gear doing cleanup last winter.


John

[GAZOU]

Hello

if I may say so,
the speed of the video is very nice!
it perment a novice to see the breakdown of movements.
I think she should not tire mechanics.
the few I've seen mechanical turn turning more slowly. too slowly.

Congratulations for your dedication 

[BarryM]

John,
A very interesting website and the speeded-up 'Bringing Her Home' video is good fun. If the aim is to demonstrate valve movement etc., I think you are going to have to bypass the turning gear and arrange a slow-speed drive direct to the flywheel or similar. That will give the effect without over-stressing the original turning-gear - but I suspect that you are already coming around to that?
Best of luck with the restoration.
Barry M

[Seacommander]

Hello,

Looks a fine set!

I don'd know the answer to your question, however, the SS Great Britain, at Bristol has a dummy engine which turns to 'give the effect' and very realistic as well.

May be you could approach them for advice....

Great project - very best of luck

Cheers

Mark 

[oldiron]

Hello,

Looks a fine set!

I don'd know the answer to your question, however, the SS Great Britain, at Bristol has a dummy engine which turns to 'give the effect' and very realistic as well.

May be you could approach them for advice....

Great project - very best of luck

Cheers

Mark

Mark

 Thanks for the lead. Worth looking at.

John

[superqualicast]

Its really a good project. I would like to best wishes for this project.

[oldiron]

Its really a good project. I would like to best wishes for this project.

Thanks very much

John