The Institution of Certificated Mechanical and Electrical Engineers, South Africa

Welcome to another edition of the Western Cape News Bulletin.
There is a new Built Environment Professions Bill (B53-2008) introduced in the National Assembly which is up for comment at
present. It has far reaching effects on the engineering profession as it stands now, and comment is called for via an advert in the papers (copy in the edition). Any submissions are required to be lodged by 12 noon on 18 July 2008 and public hearings will be conducted at Parliament on Tuesday 12 August and Wednesday 13 August 2008. If anyone would like to see a copy of the Bill, please email me – at chris@boron.co.za and I will forward a copy to you. The Institution is intending to submit necessary comment by 18 July 2008.
Further we have a continuation of the article on the electrification of Cape Town part 5 which is the last information part and the normal question and answer for GCC preparation. Also a couple of articles courtesy of SafeNet which normally make interesting and thought provoking reading. I trust that you will find the content of this news bulletin interesting
enough to pass on to your colleagues and friends.
Chris Schnehage
Tel: 083 326 8023

Local Branch News

Activities of the branch since last news bulletin were as follows:

On 15 May a large group of us did a visit and a tour of the RMS St. Helena when she was in the harbour. It certainly was an enlightening visit.
On 24 June we presented a talk on the different methods available to engineers to save power and to reduce the cost of power in installations. Also a very interesting talk attended by 22 members and guests alike.

The line up for the next few months is as follows:

15 July 2008 – visit to Ankerlig OCGT
August 2008 – COATEC – hard chrome and metal covering.
September 2008 – talk on earth fault protection
October 2008 – visit to SAPPI plant in Montague Gardens
November 2008 – Visit to Syncorp in Epping

Should any member have an interesting visit at your factory or work place, please let us know so that we can arrange such a visit. Or alternatively, if you have an idea for a talk that we could arrange, please let us know and we will attempt to find someone to present.
Later on in the year we intend to host a 1 day seminar titled “Occupational Health and Safety – Where do you fit in?” We would greatly like to hear from members whether you have something specific you would like to hear about or could contribute to the broad subject on the table. This far we have heard nothing from members. Would there be an interest out there?
We look forward to seeing you at one of our functions.
Ciao for now!
Chris Schnehage
Tel: 083 326 8023

Visit to RMS St Helena

On the 15th May 2008, the Institution of Certificated Mechanical and Electrical Engineers was permitted to visit the RMS St Helena in Table Bay Harbour by courtesy of the ships agents Andrew Weir Shipping. The 6,767 gross tonnes vessel is part passenger, part cargo specially built for regular runs in the South Atlantic between Cape Town and the islands of St Helena and Ascension as well as occasional voyages to Tristan da Cunha, Tenerife and Great Britain.
Built in Aberdeen in 1989 for St Helena Line Ltd. of Sutton Surrey. UK. She entered service in 1990. Length 105 metres. Beam 19.2 metres. Maximum Draft 6.016 metres. Normal Maximum speed 14.5 knots. Passenger capacity 128 persons.
The visit, led by WC Branch Chairman Chris Schnehage, was enthusiastically supported and a full complement of visitors went aboard. We were delighted that Mike Jaffe was with us to add some comments along the way because he had travelled to St Helena Island on the vessel. Some visitors were contemplating a voyage on the ship and surely after this visit they have already signed up! We were ushered down to the engine room by an Engineer who was born on the island.
We had a comprehensive tour of the machinery spaces. Main engine room - housing the twin six cylinder turbo-charged Mirrlees-Blackstone diesel engines, which run on Heavy Fuel Oil (HFO) when under power or gas-oil while idling. There are waste heat boilers attached to the engine exhausts. Auxiliaries’ room houses twin Ruston diesel alternators to provide electrical power. These can be synchronised if required. Twin Compair air compressors housed in acoustic enclosures, refrigeration equipment for both cargo and ship use, evaporators (to make potable water and sewage treatment equipment. The aftermost machinery space houses the hydraulically operated steering gear mounted directly on the rudder pintle. We spent time in the control room where there is comprehensive monitoring equipment and control gear. Generally the main engines run at constant speed and vessel speed and direction is controlled via variable pitch on the screws (propellers). In the event of a main engine being shut down for any reason with the ship under way, there is a clutch on each reduction gearbox which allows disconnection of the drive and by feathering the propeller pitch the affected propeller is then able to rotate freely and thus considerably reduce drag.
We then ascended to the uppermost level to visit the bridge from where we were able to see the navigation and communication equipment. We were also able to look down on cargo loading into the two holds on the fore-deck. The ship has powerful derrick cranes because at her ports of call at St Helena and Ascension Islands she has to unload her cargo into barges for ferrying to the sea wall, because there are no harbours. We returned via the accommodation spaces where we were shown the cabins for passengers, playroom, lounge which also has a library corner and the after-deck with swimming pool. Those of us who have previously interacted with `the Saints’ as the population of St Helena are affectionately known were once again charmed by their friendliness and by their unique accent. Altogether a very instructive and enjoyable visit. http://www.rms-st-helena.com . This comprehensive web-site includes an excellent video of a journey on the ship and tour of St Helena island.

GCoC Examination Q&A: Plant Eng. June 2008 [2.1] (Compulsory)

Question:
A standby 3 phase alternator has a rated voltage of 3 300 Volts (line). The stator winding is star connected and has a resistance of 0.37 Ω per phase and a synchronous impedance of 4.3 Ω per phase. Calculate the voltage regulation of a load having power factors of: 2.1.1) Unity; 2.1.2) 0.8 lagging.
Answer:
Please download the pdf version to view the worked answer.

GCoC Examination Q&A: OHSAct. June 2008 [5 & 10]

Question 5.1
In terms of the FR, every employer shall provide sanitary facilities at the workplace in accordance with the National Building Regulations, provided that where less than 11 persons are employed on one premises, the employer may make arrangements that the employees use closets and washbasins on an adjoining premises. Under what conditions may you make such an arrangement? (3)
Answer: 2(2)(a); 2(b)(i)(ii)

Question 5.2
When must an employer prohibit smoking, eating and drinking at the workplace? (4)
Answer: 5(1)(a)(b)(c)(d); 6(a)(b)

Question 5.3
In terms of the MH I R, an employer shall notify the chief Inspector, provincial director relevant local government in writing, of the erection of any installation which will be a major hazard installation, prior to commencement of the erection thereof. This notice shall include a risk assessment of the risks associated with the major hazard installation. Name THREE items that must be included in the assessment. (3)
Answer: 5(b)(i)(ii)(iii) up to (xii)

Question 10.2
In DMR, name FIVE design requirements for a lifting machine. (5)
Answer: 18(1)(a)(b)(c); 18(2)(a)(b)

Question 10.3
What must be provided on a jib crane with a lifting capacity of 5 000 kg or more, at minimum jib radius?(4)
Answer: 18(11)

Electricity in Cape Town

Part 5 of the extract from a document titled “A historical Record commemorating the Centenary of the City of Cape Town Electricity Undertaking 1895 to 1995” by Denis Palser

Athlone Power Station - First Stage: Initial (1957)

2 - Turbo-alternator sets; Oerlikon Engineering Company, Switzerland.
Twin cylinder, impulse type, with single exhaust.
12 000 V, 50 Hz, three-phase, 3 000 rpm. 30 000 kW.
3 - Boilers. Chain-grate stoker-fired type.
John Brown Land Boilers (Africa) (Pty) Ltd.
Stop valve steam pressure 635 psig at 915°F (490°C).

The first boiler underwent final inspection by the Inspector of Machinery on 26 October 1960, and a provisional permit was granted to raise pressure and steam the boiler. Soon afterwards, on 8 November 1960, the first turbo-alternator was run up and connected to the system for testing purposes, but because of balancing and adjustment problems this unit only became available for regular operation on 11 January 1961. The second turbo-alternator was placed in commercial operation soon after the first.
First Stage: Optional (1958)

1 - Turbo-alternator set. Oerlikon Engineering Company, Switzerland.
Twin cylinder, impulse type, with single exhaust.
12 000 V, 50 Hz, three-phase, 3 000 rpm. 30 000 kW.
1 - Boiler. Chain-grate stoker-fired type. John Brown Land Boilers (Africa) (Pty) Ltd.
Stop-valve steam pressure 635 psig at 915°F (490°C).

Station total installed generating capacity 90 000 kW. This third turbo-alternator was placed in commercial operation later in the year, soon after the second, thereby making available a total of 90 MW of extra generating capacity on the Council system. Initially this plant was operated daily on a two-shift basis only, but the following year, 1962, it was run on a continuous three-shift basis throughout the year to meet the increased nightload on the Council's stations. The power station was officially opened by the Mayor, Councillor A H Honikman, on 15 August 1962, and named the Athlone "A" power station.
Second Stage: Initial (1963)

1 - Turbo-alternator set. Oerlikon Engineering Company, Switzerland
Twin cylinder, impulse type, with single exhaust
12 000 V, 50 Hz, three-phase, 3 000 rpm.
30 000 kW.
2 - Boilers.
Chain-grate stoker-fired type. John Thompson Africa (Pty) Ltd.
Stop-valve steam pressure 635 psig at 915°F (490°C).

By the end of 1963 a fourth turbo-alternator and fifth boiler had been commissioned, further raising the available capacity of the station to 120 MW.
Second Stage: Optional (1964)

1 - Turbo-alternator set.
Oerlikon Engineering Company, Switzerland.
Twin cylinder, impulse type, with single exhaust.
12 000 V, 50 Hz, three-phase, 3 000 rpm. 30 000 kW.
1 - Boiler. Chain-grate stoker-fired type.
John Thompson Africa (Pty) Ltd.
Stop-valve steam pressure 635 psig at 915°F (490°C)
Station total installed generating capacity 150 000 kW

Third Stage (1965)

1 - Turbo-alternator set.
Single cylinder type. Hitachi, Japan.
12 000 V, 50 Hz, three-phase, 3 000 rpm. 30 000 kW.
1 - Boiler.
Chain-grate stoker-fired type.
John Thompson Africa (Pty) Ltd.
Stop-valve steam pressure 635 psig at 915°F (490°C).
Station total installed generating capacity 180 000 kW

This sixth turbo-alternator and eighth boiler went into commercial operation on 1 April 1967, some ten years after the first contracts were placed. The station was now fully equipped to its ultimate generating capacity of 180 MW.

Steenbras Power Station

4 - Reversible Pump-Turbine Motor-Generator sets.
Pump-Turbines: Francis type. Escher Wyss Ltd, Switzerland.
Motor-Generators: Salient-pole, synchronous type. Siemens Ltd, West Germany.
12 000 V, 50 Hz, three-phase. 45 000 kW.
Station total installed generating capacity 180 000 kW

The station was formally opened by the Mayor, Alderman Ted Mauerberger, on 8 August 1979. Among the distinguished guests present was Dr H Olivier, the President of the South African Institute of Civil Engineers, who unveiled a presentation plaque marking the Institute's recognition of the civil engineering works associated with the scheme as the most outstanding civil engineering project completed during 1978. Steenbras power station has the distinction of being the first hydroelectric pumped- storage installation to be built and commissioned in South Africa, and probably also the very first on the African continent.