Electric with Acetylene Standby

[island]

In the Welcome Forum Eddystone stated he is seeking to obtain an electric/acetylene autochanger. As he describes, this device was used for an electric light and would automatically change to acetylene when the bulb burned out.

I am not familiar with such a device. I did find on the web that Donaghadee light on the northeastern coast of Ireland had one of these installed in October 1934 when this light was automated. A standby acetylene light was “fitted to the lamp changer” and would operate automatically if the electric lamp failed or electric supply failed. The acetylene light was discontinued in 1967 when a standby generator and a two-bulb lamp changer were installed.

This question comes to mind. What caused the acetylene light to come on when the power failed?

I am assuming the acetylene pilot light ran continuously but some device existed to cause the main acetylene supply valve to open when the electric power failed. A heat sensing device, perhaps, activated the acetylene lamp when no heat was present from the electric light bulb.

Also, were any U.S. lighthouses ever equipped with acetylene standby lamps?

[Optics]

The acetylene - electric changer is shown below. The two electric bulbs are on a rotary changer and when one filiment fails they rotate and bring the second bulb into position at the focal point of the lens. All this time the acetylene pilot has been on in case the second filiment burns out. When both filiments are burned out a solenoid activates and the whole metal arm pivoted on the left in the photo moves up bringing the acetylene burner up to the left into the focal position. When the pivot arm raises it also activates the flow of acetylene to the burner fully powering the acetylene burner.

These changers were used widely in Europe, but I am unsure if any were ever used in the US.

[island]

This certainly was an innovative device. So what powered the repositioning of the Acetylene lamp if the electric power supply failed?

[Terry_Pepper]

I will hazard a guess (and its just a guess) that the assembly was spring-loaded, and was held in place by a solenoid which operated in an extended position whenever power was present. With a loss of power, the solenoid would retract, releasing the mexchanism to snap the acetylene unit into position.

[Optics]

I agree with Terry. I too am not absolutely sure, but I think the solenoid was maintained in the on position so that a power failure would allow the solenoid to relax and that would allow the assembly to raise and turn on the acetylene.

[island]

So this was similar to the operation of the electric lamp changers used in the U.S.

"With one type, the operating lamp is held in place by a holding coil in series with the filament, when the filament burns out the holding coil is de-energized, permitting the carrriage to change position by a spring arrangement bringing the spare lamp into position. Others, upon opening of the filament circuit, released a spring operated mechanism which serves to bring the spare lamp into position."

One thing always seems to lead to another. In the process of searching the AToN manual for the lamp changer information I discovered that AGA sun valves were used for electric lamps. The S-20 was used with acetelyene and the SR-20 for electric.

David