Breaker Point High Quality

A contact breaker (or "points") is a type of electrical switch, found in the ignition systems of spark-ignition internal combustion engines. The switch is automatically operated by a cam driven by the engine. The timing of operation of the switch is set so that a spark is produced at the right time to ignite the compressed air/fuel mixture in the cylinder of the engine. A mechanism may be provided to slightly adjust timing to allow for varying load on the engine. Since these contacts operate frequently, they are subject to wear, causing erratic ignition of the engine. More recent engines use electronic means to trigger the spark, which eliminated contact wear and allows computer control of ignition timing.

breaker point

The contact breaker is operated by an engine-driven cam. On an engine with a distributor, the contact breaker can be found beneath the distributor cap. The position of the contact breaker is set so that it opens (and hence generates a spark) at exactly the optimum moment to ignite the fuel/air mixture. This point is generally just before the piston reaches the top of its compression stroke. The contact breaker is often mounted on a plate that is able to rotate relative to the camshaft operating it. The plate is most typically rotated by a centrifugal mechanism, thus advancing the ignition timing (making the spark occur earlier) at higher revolutions. This gives the fuel ignition process time to proceed so that the resulting combustion reaches its maximum pressure at the proper point in the crankshaft's rotation. [1]

A drawback of using a mechanical switch as part of the ignition timing is that it is not very precise, needs regular adjustment of the dwell (contact) angle, and at higher revolutions, its mass becomes significant, leading to poor operation at higher engine speeds. These effects can largely be overcome using electronic ignition systems, where the contact breakers are retrofitted by a magnetic (Hall effect) or optical sensor device. However, because of their simplicity, and since contact breaker points gradually degrade instead of catastrophically failing, they are still used on aircraft engines.

The breaker point ignition system circuit starts and ends with the battery. When the engine is running the battery is continuously being recharged by an alternator or, on older systems, a generator. Current flows from the positive terminal of the battery to the ignition switch and an ignition coil. The ignition coil is really a transformer that steps up the 12-volt current of the battery to somewhere in the neighborhood of 25,000 volts. In engines of medium to high compression this kind of voltage is necessary to reliably arc across the gap on a spark plug and make enough fire to ignite the fuel/air mixture in a cylinder.

The coil has two circuits in it; the primary, which runs from the positive coil terminal to the negative coil terminal; and the secondary circuit, which goes from the positive terminal on the coil to the ignition wire in the center of the distributor cap. The negative wire on the primary circuit runs from the coil to the base of the distributor and the breaker points inside. This may sound a little confusing, but it makes sense when you understand that the points act to open and close the ground circuit.

The breaker points open and close as the distributor shaft rotates. One half of the point set is fixed, the other half pivots and there is a rubbing block on the moveable half of the point set. The distributor shaft has lobes that contact the rubbing block. These lobes act as cams to push the points open, thereby breaking the electrical connection between the points. The points have a spring clip that acts to hold the points shut, and this spring causes the moveable point to snap back into contact with the stationary point mounted to the distributor plate when the cam rotates out of contact. If this is unclear, take the distributor cap off of a breaker point-equipped engine and rotate the engine manually, watching the parts move. The interplay will become obvious.

The spring clip is electrically insulated from the distributor body so that the primary circuit is grounded only when the points are closed. When the points are touching each other electricity runs from the battery, through the coil and to the engine block, which is grounded to the negative terminal on the battery. The current running through the windings in the ignition coil builds up a powerful electrical field that is unleashed when the points separate. No longer able to go to ground through the points, the electricity, which is seeking the easiest path to ground, rushes through the secondary circuit to the coil wire to the top of the distributor cap where it is transmitted to the distributor rotor.

Push down hard on the boots at the end of the spark plug wires to make sure that they are on securely. Take a glance at the points; if they look corroded replace them. Check the gap between the points (the space formed when the points are at their widest open setting) with a feeler gauge, getting the proper specification for the gap from a repair manual. A typical setting is 0.015- to 0.020-inch. Use a socket and a breaker bar to rotate the engine so that the points are at their widest gap. The gauge, either a wire type or feeler type, should just slide between the points without pushing them apart.

Rotate the engine until the points are closed. Use the multi-meter to test for a good connection between the points. A slight gap when the points are supposed to be closed will keep your machine from running.

Starting at the battery cables go around the circuit testing each wire and connection. Block the points open and place each probe on one of the points. If the light goes on you have found the problem. Look carefully to find the bare patch of insulation or missing rubber washer on the distributor wire.

The primary circuit carries low voltage. This circuit operates only on battery current and is controlled by the breaker points and the ignition switch. When the ignition key is turned on, a low voltage current from the battery flows through the primary windings of the ignition coil, through the breaker points and back to the battery. This current flow causes a magnetic field to form around the coil.

The secondary circuit consists of the secondary windings in the coil, the high tension lead between the distributor and the coil (commonly called the coil wire) on external coil distributors, the distributor cap, the distributor rotor, the spark plug leads and the spark plugs. As the engine rotates, the distributor shaft cam turns until the high point on the cam causes the breaker points to separate suddenly. Instantaneously, when the points open (separate) current flow stops through the primary windings of the ignition coil. This causes the magnetic field to collapse around the coil. The condenser absorbs the energy and prevents arcing between the points each time they open. This condenser also aids in the rapid collapse of the magnetic field.

As the distributor continues to rotate, electrical contact between the rotor and distributor cap terminal is broken, stopping the secondary flow. At the same time, breaker points close to the complete the primary circuit, allowing primary current to flow. This primary current will again create a magnetic field and the cycle is repeated for the next cylinder in the firing order.

The X-PROFILE series features a special construction, in both a Pyramidal and Chisel version. These styles provide self-sharpening of the point and a well-balanced wear right through the entire body of the tool. Unlike the standard tool shape, the grooves of the X-PROFILE allow the crushed particles to travel up the shank thus allowing for constant tool penetration. This eliminates the build up of dust so the tool resists overheating and maintains its strength.

Circuit breakersCircuit-breaker points represent the thresholds at which trading is halted market-wide for single-day declines in the S&P 500 Index. Circuit breakers halt trading on the nation's stock markets during dramatic drops and are set at 7%, 13%, and 20% of the closing price for the previous day. The circuit breakers are calculated daily.

CSD100 GE's new CSD100 is an advanced Controller Switching Device for high voltage AC circuit-breakers. The ability to migrate switching transients is becoming a key issue for today's grids as the generated stresses lead to power quality problems and accelerated aging. More Info

When a transformer is energised it may draw a large transient current from the supply connection point. This large current may lead to voltage dips in excess of allowed standards and limits. Due to this it has been common practice to install a Pre-insertion Resistor (PIR), that is placed in circuit during the transformer energisation to reduce the inrush current and thus voltage dip. However, a PIR requires an extra circuit breaker, has a significant footprint and can be expensive. The SynchroTeq is a controlled switching device that can provide equal or better inrush mitigation to that of a PIR without the need for an extra breaker or costly install.

Point-on-Wave switching has been around for a number of years, and has been more commonly applied to large grid connected transformers with IPO circuit breakers. However, with the release of the Vizimax SynchroTeq device, Point-on-Wave (PoW) switching is applicable to any size of transformer and can be used effectively on 3-pole operated circuit breakers.

When a transformer is de-energised, the magnetic core will contain a certain amount of residual magnetic flux. This residual flux is dependent on the voltage across the transformer at the time of de-energisation and can intensify saturation leading to a high transient inrush current and thus voltage dip on re-energisation. The possibility or magnitude of saturation and thus inrush current is dependent on the point of re-energisation (angle) in relation to this residual flux. 041b061a72