Sparks Electrical News April 2015

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sparks
ELECTRICAL NEWS april 2015
MAY FEATURES
Energy management, load management,
load shedding, load control devices, meters,
transducers, lamps, lighting control, timers,
water heating, time-of-use tariffs, power
factor correction, relays, heating, ventila-
tion, air conditioning, control gear, alterna-
tive energy.
Enclosures, earth leakage devices, circuit
breakers, fuses, surge and lightning protec-
tion, metering switches, dimmers, sockets,
disconnectors, Certificate of Compliance,
testing and measuring instruments, tools
and accessories, cabling glands, flameproof.
ENERGY EFFICIENCY
DISTRIBUTIONBOARDS, SWITCHES,
SOCKETSANDPROTECTION
This publication is distributed to electrical contractors,
wholesalers, distributors, OEMs, panel builders, Eskom,
mining electricians and consulting engineers (electrical)
as well as libraries, members of IESSA and public utilities.
Sold 51, free 6 754, total 6 805 per month.
Editor:
Erika van Zyl
Consultant:
Ian Jandrell PrEng, BSc(Eng), GDE, PhD, FSAIEE, MIEEE
Production & layout:
Colin Mazibuko
Advertising:
Carin Hannay
Managing member:
Jenny Warwick
Publisher:
Karen Grant
Published monthly by:
Crown Publications cc
P O Box 140
Bedfordview, 2008
Tel: (011) 622-4770
Fax: (011) 615-6108
e-mail:
Website:
Printed by:
Tandym Print
The views expressed in this publication are not
necessarily those of the editor or the publisher.
Bright Sparks
March solution
Amixed collection
Tommy's collection of pets was his pride and
joy. He had snakes, several birds, rabbits and
also some cats. Altogether his entire collec-
tion of animals had 15 heads, six wings and
38 legs.
Howmany snakes did he keep?
In this diagram, the moves have been abbreviated to
show that all you have to do is move the top two coins
(which you know takes three moves); thenmove the
third coin (one move); and finally, move the top two
coins again (another three moves).
Now the pattern is easier to see. Tomove four coins,
you first move the top three coins (sevenmoves). Then
move the fourth coin (one move) and thenmove the
top three again (sevenmore moves) – a total of 15
moves. The number of move required for four coins is
one more than double the number required for three
coins. By the same pattern, the number of moves
required tomove five coins would be 15 + 1 +15 = 31
A tower of coins
The simplest way to solve this puzzle is to solve the
same puzzle with fewer coins, and then work up to
four coins.
Tomove one coin takes of course, just one move
Tomove three
coins takes
sevenmoves
like this
Tomove two
coins takes three
moves like this
people on the move
28
Voltex
Jacques vanWyngaard,
sales manager,
Free State Admin
branch.
ifmelectronic SA
Albert Louw,
product specialist, mobile
control systems,
Centurion.
Cornel Swart,
field sales engineer,
Centurion.
Stuart Munstermann,
field sales engineer,
Durban branch.
Royal HaskoningDHV
Salani Sithole,
managing director,
South African operations.