Fitting a working governor to a Cotswold Heritage beam engine.

[Jennifer Edwards]

Governor as purchased

Pulley flipped

Governor located in design position

Vertical view of pulley over pillow blocks


I have been building one of the Cotswold Heritage “Stothert and Pitt” beam engines and while I found it a very well designed engine, I was disappointed in the non-functional governor called for in the plans.

In an attempt to remedy this shortfall I picked up one of those ready built ball governors available in a few places on-line and stocked by a few of the dealers who make the model engineering show circuit.

I found that they are of the perfect height and scale to fit in the space designed for it with no modifications to the original design.

The only engineering problem was to figure out how to drive it.

The solution was so simple I thought I would share it here for other’s to see.

When placed with the steam outlet over the design hole under the Center of the entablature the pulley was too far outboard of the pillow blocks that were located to drive the original ornamental governor.

After thinking of about a half dozen crazy “Rube Goldberg” solutions it dawned on me that simply loosening the set screw on the governors pulley and flipping the pulley around it lined up perfectly in the Center of the pillow blocks designed for the purpose of driving the “stock” governor.

All I need do now is turn a matching pulley to fit between the pillow blocks and plumb the steam output thru the existing hole in the base and up thru the hole already located in the base to feed the steam chest.

I did not have to change the location or size of any of the forty or so holes on the base that I previously located, drilled, and tapped as per the blueprints.

The only change to the original design is that the steam input will now be on the side of the engine rather than thru the base.

When I finish assembling my engine I may have to experiment with either the governors spring tension or the pulley size to get the governor to perform properly.

It does not get any easier than this!

 

[gbritnell]

Hi Jennifer,
The governor on my Mary beam is functional but the engine runs at such a slow speed the governor never reacts. When I speed it up to an unrealistic speed (although not that fast) it will control the throttle. It's just more the fact that it looks interesting spinning while the engine is in motion.
gbritnell

 

[Jennifer Edwards]

Hi Jennifer,
The governor on my Mary beam is functional but the engine runs at such a slow speed the governor never reacts. When I speed it up to an unrealistic speed (although not that fast) it will control the throttle. It's just more the fact that it looks interesting spinning while the engine is in motion.
gbritnell

I loosened the spring to where it will govern at quite a slow speed. J am sure I will still need to dial it in once i get it assembled and begin testing.

 

[Jasonb]

Drive it with as large a pulley as you can fit in so that it runs as fast as possible.

 

[Jennifer Edwards]

Thanks Jason

I plan on starting with a 1:4 ratio, which is where I have set it up, that should give me what I am looking for.

These governors are surprisingly efficient and quite sensitive to adjustment, considering their small size.

Once the engine is finished hopefully it will be close and all I will have to do is “dial it in” adjusting the spring tension a bit.If I have it wrong I can always gear it up as you suggest.

As I have it set now it will fully close under 60 lbs. of steam at 180 rpm. That would equate to 45 strokes per minute at a 1:4 ratio.

Thanks again,
Jen