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Selección de la potencia nominal

In document INSTALACIONES ELÉCTRICAS (página 136-140)

INSTALACIONES DE CONEXIÓN

4.2. Centros de transformación

4.2.3. Diseño del transformador de un centro de transformación

4.2.3.1. Selección de la potencia nominal

Question: Why would White develop the bishop to

a passive square when d3 is available?

Answer: In the main line of this chapter White usually goes for the set-up Bd3, e5 and Be4. In the 6

Be2 line White seeks a similar plan: Be2, Bf3 and e5.

Question: So are the two lines essentially equivalent?

Answer: I don’t think so. We can mess White up in this one, since his plan contains the seed of a few

flaws in both scenarios:

1. If we play 6 ... Nd7 and he responds with 7 Bf3, then we play 7 ... e5!, which throws a monkey wrench into the works of his plan.

2. If we play 6 ... Nd7 and he responds with 7 e5 we simply move our rook to b8. White’s problem now is his bishop sitting on f3 eats up the g1-knight’s best square. Also, Black generally castles kingside sooner or later in this line. If this is the case, then why did White aim his light-squared bishop in the opposite direction, and at a waste of time to boot?

6 ... Nd7!

Given the Tiger seal of approval as well. 6 ... b4 is the main move, but as Tiger points out in his Modern book, 7 Na4! is quite awkward for Black.

Question: Don’t you mean the other way around?

What does White’s knight do on a4?

7 Bf3

Question: What if White beats us to ... e5 by playing the move himself?

Answer: After 7 e5 we can play 7 ... Nb6! 8 Bf3 d5! (now White’s f3-bishop aims the wrong way) 9

b3 Nh6 (9 ... h5!? intending ... Nh6 next move is an untried option, and probably what I would play in the position) 10 g4!? f6 11 h3 Nf7 12 Qd2 fxe5 13 dxe5 e6 14 g5 Qe7 15 Qf2 Nd7 (15 ... Bf8! is a possible improvement; Black gets to roll his central pawns after 16 Nge2 c5) 16 Bxd5!? Nfxe5! (16 ... exd5 17 Nxd5! gives White a lot for the piece) 17 Bxa8 Nd3+! 18 cxd3 Bxc3+ 19 Ke2 Bxa1 20 Nf3 Bg7 and the game is up for grabs for either side, D.Marciano-B.Avrukh, Cappelle la Grande 1999.

7 ... e5!

Gumming up White’s e5 plan. 8 dxe5

White’s best plan may be to retain central tension. After 8 Nge2 Bb7 9 a3 Ngf6 10 0-0 0-0 11 dxe5 dxe5 Black completed his development with a good position, E.Aranovitch-E.Neiman, Cannes 2007.

White loses time with 9 Qd5?!. He is better off playing to d2 right away. After 9 ... Rb8 10 0-0-0 Ngf6 11 Qd2 Bb7 12 g4 b4 Black already had the initiative in a position which looks like a souring Open Sicilian for White, J.Hector-T.Hillarp Persson, Swedish League 2004.

9 ... Bb7 10 Nh3 Ngf6

Now ... b4 is in the air. 11 a3

The weaker 11 Nf2?! b4 12 Na4 gxf5! 13 exf5 e4 14 Be2 was Z.Lanka-P.Petran, Groningen 1991, and now Black can take over the game with 14 ... Nd5! 15 Qd2 Bc6.

11 ... Qe7

Black stands better after 11 ... gxf5! 12 exf5 e4 13 Be2 Qe7 14 0-0 0-0-0!. 12 g4 gxf5 13 gxf5 Nb6 14 Qe2

The trouble with 14 b3 Nfd7 is that White can’t castle long anymore, but perhaps this is how he should play.

14 ... Nc4 15 Bc1

White avoids 15 0-0-0?! Nxa3!. 15 ... Nd7

Better is 15 ... 0-0-0 16 b3 Na5!, intending ... Nc6 and ... Nd4, with the initiative. 16 b3 Nd6 17 Nf2 Rd8?!

I don’t think Black has anything to fear if he castles queenside. 18 Be3 Bf6!

A future ... Bg5 bishop swap would leave White with a remaining bad bishop. 19 Rg1 h6 20 0-0-0?!

It turns out White’s king is a lot safer in the centre or on the kingside. 20 ... Nc4!

The c4-square is the platform from which Tiger’s boorish knight insists on monopolizing the table conversation.

Exercise (critical decision): Black’s last shot was undoubtedly a surprise

for White and a much needed transfusion of reserves for Black’s attack. The question is should White accept the knight or not?

21 bxc4?

Answer: White had to suck it up and decline with 21 Kb1. Then I would even consider not taking the

pawn and going for the dark squares with 21 ... Nxe3! (White gets compensation in the line 21 ... Nxa3+ 22 Ka2 Bg5 since Black’s a3-knight remains out of play) 22 Qxe3 Qc5!.

21 ... Qxa3+ 22 Kd2?

The leaky quarters of the queenside grow unbearable for White’s clumsy king, while Black’s forces have the appearance of limitlessly multiplying. Admittedly the line 22 Kb1 Qb4+ 23 Ka2 Qxc3 24 Qd3 Qxc4+ 25 Qxc4 bxc4 seems unappealing for White; nevertheless, this is how he should play it.

22 ... Nb6+ 23 Nd5 Nxc4+ 24 Qxc4!?

Answer: Using a salad fork on your main course is inappropriate. This questionable show of force

goes way past inappropriate, as White hopes his soufflé rises twice! White’s once repressed queen vents her grievances with a passionate outpouring of emotion, as White throws away material as if it were a free and ever-replenishing commodity. He may have been better off trying the slightly less hopeless option 24 Ke1 Bxd5.

24 ... bxc4

Well, Adam Smith in The Wealth of Nations did warn of the societal dangers of wealth concentrated in the hands of a few.

25 Ra1 Qb4+ 26 Ke2 Bxd5 27 exd5 Bg5 28 Ne4 Bxe3 29 Rgb1 Qe7 30 Kxe3 Qh4 31 Rxa6 Qf4+ 32 Ke2 Qxh2+ 33 Ke3

The queen’s love for White’s king goes unreciprocated, as he continues to reject her advances. 33 ... Rg8!

Question: Why did Black deliberately walk into the knight fork?

Answer: The knight is White’s last truly dangerous piece, so Black would be happy to swap a rook

for it. 34 Nf6+ Kf8 35 Nxg8 c3! is quite awful for White, whose exhausted king, hoping to get a few hours of much needed sleep, too soon finds the morning light leaking through the shutters, waking him up.

34 Rh1 Qxc2 35 Rhxh6 Rb8 36 Nf6+ Kd8! 0-1

White’s knight nods, as if acknowledging a private meaning. The ‘hanging’ rook can’t be touched: 37 Nxg8 Rb3+ and the rook sends White’s king to eternity, wherever that is.

Summary

The 6 Be2 plan strikes me as over-clever and under-effective. We can mess White up by meeting it with 6 ... Nd7!.

In document INSTALACIONES ELÉCTRICAS (página 136-140)