Lucien's vintage fairground electrics thread

[DPG]

Lovely.

Just a shame the internet can't provide the steam rally smell and a pint or three of real ale.

 

[Lucien Nunes]

That was on the Saturday evening of the 50th anniversary show, which holds a Guinness World Record for the greatest number of steam-powered vehicles at an event (over 500). I did count the number of Showmans engines with their dynamos belted up that evening but can't remember now, I'm sure it was over 80. Some were powering rides, some powering organs, some were remaning free entities and just lighting their own canopies.

The Sunday was bizarre, there had been a storm overnight and heavy rain continued through the day. Half the exhibits were under wraps but Kat and I still had a load of muddy fun. One of the intrepid operators who was bracing the weather was David Downs who had his Tidman 3-abreast steam gallopers (G4) up and running. We walked up when no-one else was around and got an extra long and fast ride as the boiler had a full head of steam to be used up.

 

[pc1966]

Dolphin was one of the very last Special Scenics built by Burrell, with larger LP cylinder bore and 10 NHP rating. Nominal Horsepower (NHP) was an old method of describing the size of a steam engine based on piston speed and bore, but it is not an actual rating of power equivalent to BHP (brake horsepower) or watts. Dolphin is capable of

Just like the CV in the Citroen 2CV = chevaux-vapeur (so steam horses)

Quite a few countries had odd ways to tax vehicles based on the engine but for various reasons (probably simple but stupid) many based it on the engine size rather than actual output. As far as I remember the UK at one point had one on piston diameter which lead to long-stroke engines being common, if not terribly good, in 1940s cars (i.e. to get less tax band for a given displacement).

 

[Darkwood]

I have no pictures and modern tech' sees no need for such systems anymore but had a wire drawing machine that would pull a wire through several shaping dies, each die was proceeded by a motor and because each die was tensioned differently the motors all had to have automatic variable speed control, this was done with what are called dancers, the cable would loop around 3 pulleys, 2 fixed and a floating pulley, the floating pulley is attached to a variable resister as seen on the fairground photos which as the wire tightened or loosened would automatically change the speed demand on the following motor.
We usually had a master motor with user speed control and the rest were slave motors working off the dancers, effective but dated as you had to have a large DC gen' in the basement to tap a secondary supply of for your machines, wish I had the pictures, we had a lot of fun replacing the DC motors when the variable units failed with age, trying to match AC VSD's to seek a set point in torque feedback mode wasn't as simple as you might theorise unless you did the whole line, we hit many a tech' walls during the repairs, modern versions have several AC drives and are linked to each other in the controls still using dancers but using a linear transducer instead of a variable rotary resistor, the master speed control would maintain the master motor speed and drive control links would trim the voltage signal from each transducer return voltage, our issue was having an electrically isolated AC drive reacting to a line of DC motors, it was the reaction time of modern tech that often created a issue as it had no master analogue feedback and just looked at its own dancer, often we had to train the operator to manually ramp up speed in a certain way to allow a smooth start up, it was starting the lines that were the issue, many a snapped wire was done and with a 15minute set up time it was a long learning curve.