Thursday 7 November 2019

Electricity Supplies


By Jack Vaughan

Ted Barr’s survey of electrical generation in the area in the last Newsletter (November 2001 Vol.4. No.6. p.8) is comprehensive. I would only add one item – the so-called Woolwich Tramshed in Woolwich New Road.  In fact it never had a tram inside it but was part of the London Tramway support system. I recall it having large machines, presumably generators, or alternators and transformers and a balcony full of meters and control gear.

With the disappearance of the trams the building became redundant and a prime target for destruction by the Borough. A ’Tramshed supporters club’ was set up in 1978 to protect the shed which by then housed a theatre of some note. It’s bar became a popular lunchtime rendezvous, presided over by no less a person than the present Mayor of Greenwich, Councillor Malone. The bar offered two famous ales Fullers ESB and Everard's Tiger.  In 1981 the council; approved demolition of the tramshed as part of a comprehensive development of the whole town centre. A petition of 17,000 signatures was organised without avail and a protest movement was assembled under the name of ‘Save Woolwich Now’. Battle was joined.

To cut this long story short - in the end the property company in question wilted under the local objections and pulled out.  The present popular park square was the final somewhat desperate alternative, but the future of the Tramshed can never be taken for granted. Returning to Ted’s quest for information on the generation of Electrical Power in the Royal Arsenal: -  The Arsenal comprised four factories

Royal Gun Factory (1716)
Royal Laboratories (1696)
Royal Carriage Depot (since 1895)
MED (Mechanical Engineering Depot)

Each of them had its own generation plant until 1888, when responsibility passed to the Building Works Dept. For maintenance no doubt the four relied on the workshops of the MED.

Installation of overall electrical power came in 1891. Extensive changes were needed to all types of machinery and the new central power station was completed in 1908.  From then until 1938 is a story of constant expansion. Basic energy source was coal gas from the Arsenal’s own gas factory feeding a group of boilers which in turn supplied steam to three turbines. The early output was 300 volts DC later raised to 500 volts. A three-wire system was adopted, enabling lighting to use 250 volts DC and 500 volts DC for machine power. Alternating current was not supplied until after the Second World War.

By John Day

Ted Barr is asking about the electricity supplies in the Arsenal. I have an idea that I have already written that up for somebody, I can’t remember who but I can remember more than was in my apprentice screed. So here goes: -

The Central Power Station was situated on the south side of the road running along the river front roughly just east of the present Arsenal boundary. I had a fair bit to do with it; in the early thirties my father was one of the five station engineers who looked after it on shift work. When my father was on Sunday shift, I took him a hot dinner in a basket and spent the rest of the afternoon, till we both went home, investigating the building and its contents. Later, as an engineering apprentice, I spent a month, or so, as the station engineers assistant see Vol.1 No.5 of the Newsletter.  The building comprised, from north to south, the Electrical Shop  (headquarters for all electrical maintenance), the Pump House (supplying   hydraulic pressure around the manufacturing area), the Power Generating hall and, finally, the boiler house. Along the north wall of the electrical shop were two smaller shops, for magneto repairs and for accumulator repair and charging, the foreman's office and the stores. The magneto repair was for all the Arsenal vehicles and the accumulators were mainly for the Shelvoke & Drewery electric trucks (known as 'dillies'). The south side had the door into the pump house, an armature store and a rudimentary test area. The centre was taken up by benches, two lathes and a Drummond hand shaper.

The pump house, from west to east, housed a triple expansion, scotch crank, Worthington-Simpson pump (very rusty and obviously not steamed since WW1), two - or was it three?- electrically driven, three throw, single acting, horizontal pumps, the door into the generating hall and a couple of electric centrifugal pumps for odd duties and supplying the boiler feed water softening plant. The latter was in a tower at the eastern end of the pump house and, at times, saw apprentices swimming in the clear cool water.

The generating hall, again from west to east, had a space where heavy electrical things were dumped on delivery, the 6,000 KVA Metropolitan-Vickers turbine generating set, two triple expansion, Corliss valve, 1,450 HP engines direct coupled to DC generators and a Vickers-Howden, triple expansion engine with piston valves for HP and IP and slide valve for the LP, also coupled to a DC generator.  The gantry crane serving these was the slowest ever seen, wonderful for erecting steam plant but irritating when one just wanted to move some delivered goods. To the north of the Vickers-Howden were two rotary converters, essential since the western part of the Arsenal was still DC powered while the eastern part, probably from the Plumstead gate, was AC. On a balcony, jutting from the south wall, was the black slate switchboard and, at the west end, the shift engineer's office.  Going through the door by the turbine, on the right were two Babcock & Willcox boilers and on the left were four John Thompson boilers, all with chain grate stoking. Above them were the hoppers containing the pea size coal, feeding by gravity to the chain grates. The ash from below the boilers was taken out in long narrow trucks on the 18 inch gauge railway - that narrow gauge railway had to stay operative all the time the CPS was in use, since there was only room for the narrow trucks under the boiler house. They were towed by standard gauge engines, which could back up to the outside of the boiler house.  Electrical transmission from the CPS, or, in shut down and peak times, from Warren Lane substation (connected to the power station between the Arsenal and the Ferry), was by 6,600 volt buried cables to the various substation which contained transformers and switch gear and, apart from sub 4, were unmanned. Sub 4 had a workshop and restroom attached, since it acted as an outstation of the Electrical Shop providing trouble-shooting service for the AC area that included the woodworking shops, stores and the explosives pier. 

If there are errors in this please let me know, after all I am trying to remember how it was nearly seventy years ago.

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