🍒 トロント行き格安航空券・LCC・飛行機チケットの最安値・相場を比較・予約(東京発)【トラベルコ】

And remember, if the pulley is smaller the alternator will rotate faster than normal, so you may want to limit engine revs a little to avoid over-revving the alternator. Without the warning it may need to be revved to several thousand rpm to start, and new alts out of the box may not do that. Most of the other bulb holders on CB 4-cylinder cars only need one wire as they can pick up an earth from being plugged into to metal panel or instrument case. So some care needs to be taken to determine just which type of wiring, plug and alternator you have when making changes, even swapping alternators which take the same plug. So if the engine is running and the charge does fail at some point, then you have a very good chance that the warning light will come on and tell you about it. This passes a high current through the control box and dynamo which will burn them out in quite a short time. Tip: If you carry an alternator as a spare at any time, then it's a good idea to make sure it already has a pulley fitted. If it is larger then it will rotate slower, so you may find the engine needs to be revved a bit higher before it starts charging, will stop charging sooner as the revs fall, and it may not charge at idle. Change to LED? On these you must have a large gauge brown wire on the output spade at the very least, and a smaller gauge at least on the sense terminal. But LEDs are much more sensitive to small voltages and will glow when incandescents wouldn't, including when there is no actual fault as such. The ignition warning light always had two wires connected to it which must be insulated from earth as at various times one side receives 12v from the ignition switch and the other side 12v from the alternator or control box. It's battery voltage which is important, and any volt-drop between there and the green circuit is down to ageing connections, and the best alternator in the world isn't going to cure them, although it may cover them up. However JCR Supplies shows this diode pack which is the 3-wire battery-sensing type, and I have seen the harness plug on a 78 which does match that. Only just though, as the harness plug has to be wiggled off at an angle. Hence a shorter alt that would fit directly in front of the rocker cover. This would give increased current carrying capacity and lower volt-drop now cars had electric cooling fans, offsetting the loss in voltage caused by the regulator sense terminal moving from the solenoid back to the alternator again, and despite the three wires is effectively a '2-wire' system. However they say it is for an 18ACR, which other sources indicate should be machine sensing. Clausager says the exact change point is unavailable, but thinks it was from June 76, borne out by the Parts Catalogue which shows the 18ACR being used before September The schematics get confusing here, with UK from the WSM and 'later' models for both UK and North America indicating it had reverted to machine-sensing with two thick brown wires from the two large output spades to the solenoid. This latter condition is a fault and incidentally the main purpose of the light which should be investigated before you get stranded. The warning is also part of the on-board diagnostics, and current can flow in either direction under various conditions. It was only during a discussion with someone about alternators for a V8 conversion that it became clear - the Lucas alts are too long to fit in the factory position as the rocker cover is in the way! Various other bulb holders also had two terminals at various times - Mk1 indicator tell-tales for the same reason as the ignition warning light, V8 and RB indicator tell-tales and main-beam warning lights as they are fitted to a plastic panel and so need a wired earth.{/INSERTKEYS}{/PARAGRAPH} If it's a different size then check now by trial-fitting that it is compatible with your fan-belt! Although this effect is not an issue with dynamos there is another aspect relating to the warning light acting like a pair of balance scales. Because an incandescent bulb is relatively insensitive to small voltages it will not glow, unless there is a fault resulting in a bigger difference in voltage then there should be. This residual magnetism results in a dynamo output of a couple of volts, which is passed through low-resistance windings on the cut-out and current regulator relays in the control box to the field winding. It is this feature that gives rise to the "won't switch off! You may also note that when you switch off the ignition but while the engine is still spinning the ignition warning light glows again until the engine stops. Mounting Front: With the top front mounting bolted to an ear on the water pump, there is an adjuster link on the lower front mounting. Turn all the electrical loads on you possibly can, alternator plugged in, engine running at a fast idle, then connect a voltmeter between the two large spades. {PARAGRAPH}{INSERTKEYS}The problem is that people fit voltmeters wired to the green circuit, which can be a couple of volts lower than the solenoid i. But another view has it that even idiots should be able to understand when a warning light comes on, whereas you need intelligence to understand a gauge. Dynamos are self-priming as below. The short answer is no. However someone else said that he has heard the oil warning light provided in lieu of an oil pressure gauge referred to as the 'idiot' light, because only idiots ignore it when it comes on then seize their engine. And to beat it to death, put a bullet in its brain, and hang, draw and quarter it, there are additional changes to the above in the Parts Catalogue: The original 16ACR as detailed above - part No. Early blocks only had two for the dynamo, whereas later blocks have one pair for a dynamo and another pair further forwards for an alternator. This is irrespective of whether there is 0v on both circuits ignition off, engine stationary or 12v actually around 14v when charging on both circuits ignition switched on and engine running and charging. If there is zero volts between the two large spades, then you probably have a machine sensing alternator. If it's the same size then all well and good. If your spare alt has a pulley, then compare the size with what's on the car. Prior to the 77 model year both dynamo and alternator used a flat link 12H67 or 2A and a pillar 2A on the engine front cover. In fact it usually releases at idle, lighting or flickering the warning lamp. Alternatives May I have found a Metro A 45 amp is a direct replacement on my roadster, however the pulley is slightly larger but the standard fan belt still fits so rotates slower, which reduces output, but it's good enough to carry as a 'get you home' spare. October Click the thumbnail for details on converting between 4-wire, 3-wire and 2-wire alternators. If in doubt as to which you have, it may be possible to determine by voltage measurement. An LED only glows with current flowing in one direction - unless you go to the bother of installing it with a full-wave bridge rectifier. If by looking at the two large spades on the alternator you can see they are clearly connected together, then you have a machine-sensing alternator and can use either or both large spades for the output. After-market adapters are available to mount an alternator to an early block which only has the rear-most pair of bosses. However Googling 12G shows a flat link, albeit curved with a curved slot, so the pillar is still needed. This is a 3-wire alternator, but can be used with a 2-wire harness by connecting the third spade to the output spade in the alternator plug. As stated above the warning light on alternator-equipped cars is used as a primer to start it charging, using the current through the incandescent bulb. The final variation was the 18ACR. Clausager states that a new version of the 16ACR with modified regulator and surge protection was provided in March Possibly because of problems with low battery voltage, in the alternators seem to have reverted to battery sensing again Clausager states the 17ACR was fitted from February 73 now with an additional thin brown in the alternator plug wired back to the solenoid as before, and this seems to have remained the case up to and including the 77 model year at least. This voltage now causes the dynamo to output its full voltage, which operates the cut-out relay to connect the dynamo output to the battery so charging it. They also show one with the two large spades i. If this did not happen the battery would rapidly discharge through the dynamo, which would be acting like a motor trying to turn the engine. However for on a different link was used - 12G, which the Parts Catalogue and a couple of supplier drawings seems to show is cranked, without the pillar. But if the two are clearly insulated from one another, then you have a battery sensing alternator. If both circuits have the same voltage then there is no potential difference across the bulb and it will not light. Because it has connections to both the ignition supply and the alternator or control box the bulb holder is a special in that it always has two terminals which are insulated from the body of the bulb holder so cannot short to an earthed metal panel. Even some suppliers will tell you not to fit one in this position. If you can measure any voltage between the two may only be in the order of tenths of a volt then you probably have a battery sensing alternator. See ignition schematics for more info. I don't know, but it seems to be an Americanism that is, it's Americans that seem to use the term, not that Americans are idiots as one seemed to think I meant The only thing I can think of is a point of view that says "Only an idiot would need a warning light telling them the ignition was on. For completeness my 75 V8 AC-Delco uses the same plug, both large spades are output terminals, however only one is wired as per the factory schematic with a heavy gauge brown, the other is unused and has allowed me to use it as a direct output to the cooling fan relay. These are available from various Mini parts suppliers including Moss , and given that the Metro item seems to be a direct replacement, these Mini items may be as well if you have additional loads and need a higher output. If changed to an LED the current is reduced to a fraction of its previous value and won't allow it to start charging at the normal point. If the two circuits show a potential difference i. A '2-wire' alternator i. Why 'Idiot' light? The cut-out relay has a normally open contact which disconnects the dynamo when the engine is stopped, or the output voltage drops below a certain level. With the exception of RHD cars from on with the ignition relay, the white for the warning light always comes off the ignition switch. This was the case in the 5-pin 2-plug 16ACR from 69 to Initially the 3-pin single-plug alternators used machine sensing i. So maybe, in terms of the ignition warning light, only an idiot ignores it until the battery goes flat, and as Jochen Beyer has pointed out the ignition warning light also lets you know your fan-belt has broken before you boil your coolant out. On alternator-equipped cars the warning light acts as a priming system to start it charging from about rpm. V8s and RB 4-cylinder cars have the other warning lights with two wires as well as they are fitted in plastic panels so need a wired earth. Rear: Both dynamo and alternator use their own versions of an angle bracket to attach a single mounting point on the rear end-plate to two bosses on the block. The cut-out relay has two windings, one of which ensures the relay releases as the voltage falls. The large nut is very tight and makes it very difficult if not impossible to remove the pulley from a failed unit as there is no easy way of holding the rotor still except perhaps by wrapping a fan-belt right round the pulley and gripping it firmly. Or simply provide large gauge brown wires to both large spades to cover both eventualities, and get the benefit of a lower volt-drop under high-current conditions if you have a machine sensing alternator. This is a '2-wire' alternator. The initial excitation for the dynamo field always comes from its own residual magnetism, which is why you have to 'flash' the field terminal to battery when you install a new dynamo or when you are converting from one polarity to another. It wasn't a problem for Costello as he swung the alternator out from the engine, but the factory fitted the MGB V8 filter high up on the inner wing which precluded that. Note that the lamp-holder is unique in that it has two wires - one to each side of the bulb - and the body of the holder should not be connected to earth like the panel and main-beam lamps are.