Aaron b 5/10
P&S 8/10
Time to wrap this up, I think.
1: C. Glower.
The glower is the bit that glows. It's almost too obvious. It was also sometimes called the filament but the term 'glower' was specifically associated with the ceramic rod that becomes conductive and incandescent when preheated with a voltage across it.
2: A. 19/12.
At that time, wire sizes were often given in SWG. 19/12 meant a cable having 19 strands of 12SWG wire. The lower the SWG number, the larger the wire (like AWG but different definition). 19/12 is about 0.16 sq. ins compared to about 0.12 for 37/16. The four cables in the question are in decreasing order of CSA. Many of the familiar imperial strand diameters were derived from SWG sizes e.g. 22SWG became 0.029", 20SWG became 0.036", 3/.036 was just a renaming of 3/16 etc.
3. C. Casing and Capping.
Wooden compartment trunking. An art form but so much work for even the simplest installation. Conductors of opposite polarity were not permitted to share a groove or cross in contact, so simply making a branch was a woodworking project.
4. D. Hiss when moistened.
The tinned copper wire fuse had not yet been standardised on, there were also soft-wire and weighted fuses and various patented designs. But any of them working at above boiling point was likely to oxidise and deteriorate in air.
5. D. c.p.
Most lights were at first described by their output in candle-power. Only later, once the efficacy was fairly standard amongst metal filament lamps, at about 1/2W per cp, did the wattage start to denote the size. Working in CP one could compare the light output of different kinds of light source, which cannot be done by power rating. Recently we have seen a return to light output being quoted, using lumens.
6. B. Sausage lamp.
Although heating elements were one of the widest applications of electricity in the 20th century, they got off to a slow start because until the invention of nichrome wire, there wasn't really a satisfactory alloy that had a usefully high resistance and could withstand high temperatures in air without oxidising. A high-wattage filament running at a low temperature inside a lamp was a reasonable solution at the time. Radiant heating made a comeback 50 years later with silica-tube elements.
7. C. Shunt wound.
A shunt-wound dynamo has a near-level output characteristic with a bit of internal resistance. A compound type can have a completely level characteristic which is desirable for direct running but not needed for charging. The compound machine is prone to having its residual magnetism reversed by the battery discharging into it through the series field if the voltage drops e.g. due to engine stalling, therefore less practical for a simple charging plant.
8. C. B.L.
Before lamps all had caps, one of the earliest means of attaching them to the wiring was to arrange two live hooks, over which the looped readout wires of a bottom-loop lamp would be hooked. A spring pushed the lamp away from the hooks to keep the wires in tension. Within a decade, this had fallen out of favour and the two popular types of cap, BC and ES, had become standard.
9. D. Teaser.
Some of the earliest polyphase systems, e.g. as developed by Nikola Tesla, used two phases. Not to be confused with split-phase or 2-out-of-3-phase, the two phases were 90 electrical degrees apart. This had the advantage of constant power (and hence constant torque) in motors as with 3-phase, but did not offer the economy of line plant. There were two approaches to 2-phase, one had equally-rated phases, the other had a main phase and a teaser that was only intended to be used as the second phase for motor load.
10. B. Conspicuous Mark.
There was no concept at the time of a standard for a maintenance-free connection, but it was an idea that troubled engineers from the early days. Soldering was considered to be a very permanent choice, but the insulation applied might not endure as well as the cable insulation. People jumped through many hoops to make as near a maintenance-free joint as possible, including building-up and vulcanising a rubber casing around every soldered joint. But still, there was a reluctance to hide it away without leaving an Evident Evangelist to show its location.
I should really post some pictures of some of this stuff but I'm not near any books right now. Thanks to all who participated, hopefully it provided a moment's amusement.
