Balance in mechanical terms describes the relative weight of moving components that operate in relationship with each other. According to Newton, for every action there is an equal and opposite reaction. Consider a V-8 engine. At any one moment, there are eight pistons, and eight connecting rods moving together. The crankshaft is always designed so that at least two cylinders operate in opposition, in order to cancel vibrations within the engine. The moving mass of the opposing part, cancels the motion of its compliment, preserving Newtonian balance.

The closer in weight of all moving parts, the greater will be the vibration cancellation. The greater any mismatch in mass, the greater the vibration. The inertia of the heaviest part -- in the case of a flywheel, the heaviest section--- will pull the entire engine in the direction the heaviest part is moving.

It may be possible to balance an engine by taking all matching, moving parts and weighing them. Each part is machined until it weighs precisely the same as the lightest part. This reduces moving mass and vibration, making the engine more reliable at higher RPM. Engines that have been balanced can rev higher and make more power reliably.

Bal"ance (?), n. [OE. balaunce, F. balance, fr. L. bilan, bilancis, having two scales; bis twice (akin to E. two) + lanx plate, scale.]

1.

An apparatus for weighing.

⇒ In its simplest form, a balance consists of a beam or lever supported exactly in the middle, having two scales or basins of equal weight suspended from its extremities. Another form is that of the Roman balance, or steelyard, consisting of a lever or beam, suspended near one of its extremities, on the longer arm of which a counterpoise slides. The name is also given to other forms of apparatus for weighing bodies, as to the combinations of levers making up platform scales; and even to devices for weighing by the elasticity of a spring.

2.

Act of weighing mentally; comparison; estimate.

A fair balance of the advantages on either side. Atterbury.

3.

Equipoise between the weights in opposite scales.

4.

The state of being in equipoise; equilibrium; even adjustment; steadiness.

And hung a bottle on each side To make his balance true. Cowper.

The order and balance of the country were destroyed. Buckle.

English workmen completely lose their balance. J. S. Mill.

5.

An equality between the sums total of the two sides of an account; as, to bring one's accounts to a balance; -- also, the excess on either side; as, the balance of an account.

" A balance at the banker's. "

Thackeray.

I still think the balance of probabilities leans towards the account given in the text. J. Peile.

6. Horol.

A balance wheel, as of a watch, or clock. See Balance wheel (in the Vocabulary).

7. Astron. (a)

The constellation Libra.

(b)

The seventh sign in the Zodiac, called Libra, which the sun enters at the equinox in September.

8.

A movement in dancing. See Balance, v. i., S.

Balance electrometer, a kind of balance, with a poised beam, which indicates, by weights suspended from one arm, the mutual attraction of oppositely electrified surfaces. Knight. -- Balance fish. Zool See Hammerhead. -- Balance knife, a carving or table knife the handle of which overbalances the blade, and so keeps it from contact with the table. -- Balance of power. Politics, such an adjustment of power among sovereign states that no one state is in a position to interfere with the independence of the others; international equilibrium; also, the ability ( of a state or a third party within a state) to control the relations between sovereign states or between dominant parties in a state. -- Balance sheet Bookkeeping, a paper showing the balances of the open accounts of a business, the debit and credit balances footing up equally, if the system of accounts be complete and the balances correctly taken. -- Balance thermometer, a thermometer mounted as a balance so that the movement of the mercurial column changes the indication of the tube. With the aid of electrical or mechanical devices adapted to it, it is used for the automatic regulation of the temperature of rooms warmed artificially, and as a fire alarm. -- Balance of torsion. See Torsion Balance. -- Balance of trade Pol. Econ., an equilibrium between the money values of the exports and imports of a country; or more commonly, the amount required on one side or the other to make such an equilibrium. -- Balance valve, a valve whose surfaces are so arranged that the fluid pressure tending to seat, and that tending to unseat the valve, are nearly in equilibrium; esp., a puppet valve which is made to operate easily by the admission of steam to both sides. See Puppet valve. -- Hydrostatic balance. See under Hydrostatic. -- To lay in balance, to put up as a pledge or security. [Obs.] Chaucer. -- To strike a balance, to find out the difference between the debit and credit sides of an account.

Bal"ance (?), v. t. [imp. & p. p. Balanced (); p. pr. & vb. n. Balancing ().] [From Balance, n.: cf. F. balancer. ]

1.

To bring to an equipoise, as the scales of a balance by adjusting the weights; to weigh in a balance.

2.

To support on a narrow base, so as to keep from falling; as, to balance a plate on the end of a cane; to balance one's self on a tight rope.

3.

To equal in number, weight, force, or proportion; to counterpoise, counterbalance, counteract, or neutralize.

One expression . . . must check and balance another. Kent.

4.

To compare in relative force, importance, value, etc.; to estimate.

Balance the good and evil of things. L'Estrange.

5.

To settle and adjust, as an account; to make two accounts equal by paying the difference between them.

I am very well satisfied that it is not in my power to balance accounts with my Maker. Addison.

6.

To make the sums of the debits and credits of an account equal; -- said of an item; as, this payment, or credit, balances the account.

7.

To arrange accounts in such a way that the sum total of the debits is equal to the sum total of the credits; as, to balance a set of books.

8. Dancing

To move toward, and then back from, reciprocally; as, to balance partners.

9. Naut.

To contract, as a sail, into a narrower compass; as, to balance the boom mainsail.

Balanced valve. See Balance valve, under Balance, n.

Syn. -- To poise; weigh; adjust; counteract; neutralize; equalize.

Bal"ance, v. i.

1.

To have equal weight on each side; to be in equipoise; as, the scales balance.

2.

To fluctuate between motives which appear of equal force; to waver; to hesitate.

He would not balance or err in the determination of his choice. Locke.

3. Dancing

To move toward a person or couple, and then back.

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