Renewing Alternator Brushes

Renewing Alternator Brushes

Here you can get How to Renewing Alternator Brushes.

Unlike dynamo brushes, alternator brushes normally last for several years. Electrical arcing between brushes and commutator, a major cause of dynamo wear, is way less common. Alternators carry only the sector current of two or 3 amps. The brushes are in touch with slip rings , which have a smaller, smoother surface than a dynamo commutator. The slip rings are solid rather than segmented, as during a dynamo. the click over the segments is another cause of brush wear during a dynamo.

The brushes are longer than those on a dynamo. Some alternator brushes are marked with a wear limit, but generally they ought to be renewed when worn about halfway down. Before starting work, check which make of alternator is fitted to your car. The maker’s name should be marked thereon — the kinds used most are illustrated in this section.

Depending on the sort of alternator and regulator, worn or damaged brushes or slip rings could also be indicated by the ignition red light not coming on, not going out, or simply staying dim. Check to find the cause of the matter (See Testing an alternator and checking output ). Before doing any electrical work other than circuit testing on the alternator, disconnect the battery. Generally you would like to require the alternator out of the car to replace brushes. Remove it within the same way as a dynamo (See the way to fix a dynamo ).

The way during which the brushes are fitted varies according to the make or model. On some alternators the comb holder can be removed from outside. On others the top cover must be removed. Guidance for various types is detailed below. Slip rings are seldom worn or scored enough to wish serious repair or renewal. If they’re slightly damaged, smooth them within the same way as a dynamo commutator (See Replacing dynamo brushes ), although there are not any insulation strips to chop back. take care , however, because the metal on the connection is way thinner than on a commutator. Usually, it’s only necessary to wash an error ring in position. Use a cloth or soft brush damped with denatured alcohol. Clean the comb housing and guides at an equivalent time within the same way. The brushes must slide freely into their holders. Carefully massage any high spots on them with a fine file. Always fit the right sort of replacement brushes and comes (check with the car handbook); confirm all connections and terminals are tight.

Renewing Lucas ACR brushes

Take off the molded cover at the rear of the alternator; it’s held by two recessed bolts. Use a box or socket spanner size 4BA, or an equivalent size. Locate the cable connections to the comb terminal strips, and note where each of the four leads goes, in order that you’ll replace them correctly. Remove the four terminal-retaining screws and disconnect the leads.

Some units even have a regulator field link. Loosen the bolt holding the link in order that you’ll push it aside. You can renew the brushes without removing the brush box, but you want to take it off to show the slip rings for cleaning. Take out the 2 screws holding the brush box and lift it off. The regulator earth lead could also be secured by one among the screws; note how it fits. Remove the brushes from the box complete with their terminal strips and comes . there’s a little spring fitted to at least one side of the inner brush; note which side it’s for reassembly. Clean the brush housings and insert the new brushes. Reassemble the unit in reverse order of dismantling, ensuring that each one connections are correct and secure.

Renewing Lucas AC brushes

Take out the screws securing the brush box and take away the box complete with the brushes. To remove the brushes from the box, use a small screwdriver to press each spade terminal downwards and inwards towards the brushes.

Pull out the brushes and clean the brush housings. Clean the slip rings also. To fit new brushes, insert each spade terminal from the rear of the box – the brush end. Use long-nosed pliers to tug the spade through from the opposite end until the retaining tag locks. Refit the box. Brush-wear limit: A minimum of 4 in. (5 mm) should be protruding from the housing, or the brushes should get replaced.

Renewing typical Motorola brushes

The brush box is under a cover plate at the rear of the alternator, held on by two screws. Take out the screws and carefully lift up the cover plate without straining the wires attached inside. Note how the spade connectors of the leads are fitted before removing them. Remove the two screws securing the brush box and lift the box clear.

The brushes are fixed by a screw or a bolt. they’re easily damaged lookout when removing or replacing them; don’t use force. Clean the brush housings and insert new brushes. Clean the slip rings before replacing the box, leads and cover plate.

Checking the alternator output leads

Check that all connections are secure. Start the engine and connect a voltmeter or tester across the battery terminals.

Have a helper rev up the engine from idling speed. If the voltage does not rise (or the tester lamp or headlamps don’t brighten) as engine speed increases, alternator output is just too low or isn’t reaching the battery . check that the alternator is actually turning. Switch off the engine and check the strain on the drive belt. make sure wiring to the alternator isn’t broken or disconnected.

If these checks don’t reveal a fault, disconnect the battery earth terminal and check the alternator leads with a voltmeter. There is one thick output cable from the alternator to the starter solenoid, and a smaller lead or leads. Some or all of the leads may be connected by a multi plug.

If the heavy cause the starter is separate (not on a multi plug), you are doing not need to disconnect it, and you’ll test it any time the battery is connected, using a test lamp. It should be permanently live. Disconnect the smaller leads and/or the multi plug. If the alternator has an external transformer , there’ll be separate connections to it; don’t undo these connections, albeit you’ve got to unfasten the regulator and move it aside.

Reconnect the world terminal on the battery, and turn on the ignition. Test the alternator leads by connecting each successively with the voltmeter to an earth. If there are any leads which fit on to terminals marked with an earth symbol or E, N, —, or D, don’t test them. they’re earth connections. All the positive leads should give readings of battery voltage.

If there’s a small lead marked ‘Ind’ for the ignition red light , and it alone remains dead when the ignition is switched on, the light mat have blown or be disconnected. If the other wire which need to be live isn’t , check it for a loose connection, or a breakage or faulty insulation causing a brief circuit. If all the wires are live and there’s still a fault within the charging system, it’s probably within the alternator or the regulator. Take the car to an auto-electrician. Disconnect the world terminal on the battery before reconnecting all the leads. confirm everything is reconnected securely and properly before starting the engine.


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