c200 alternator problem

[robm255]

hi guys bit new to this
a friend of mine diagnosed and refitted an alternator for me on a c200 kompressor, while he was doing this a spanner got caught between the terminal of the alternator and the bulkhead (he hadnt disconnected the battery) causing a lot of sparks.
After a trip to the shop where the alternator was refurbished they said no current was going to the alternator and that a fuse must have blown.
I have checked all the fuses in the boot, under the bonnet and behind the panel on the drivers side but these appear fine

Any other suggestions would be welcome please

 

[television]

202 or 203 car

 

[BlackC55]

Have a look under the drivers side carpet. There is a large positive cable under there and maybe a big fuse.

 

[robm255]

not sure if its a 202 or 203 i know its on a 53 plate if thats any help ?
will look under the drivers carpet and let ya know

 

[Aussie Nick]

I think you have damaged the alternator. Will probably need to replace damaged internal parts. I think it is the Diodes,but someone may be able to be more specific.

 

[television]

Have a look where BlackC55 said

your car is a 203 for ref

 

[Aussie Nick]

I don't think it is a fuse. You indicated "a lot of sparks". If this was a fuse problem there would have been a short period of arcing causing a spark which would have destroyed the fuse. A lot of sparks suggests that there was no fuse. I have seen Johnson Marine engines where the owner has miswired the battery running positive to negative and vice versa for the positive terminal. In all these cases the miswiring causes the destruction of the diodes in the alternator and damages the powerpack. There was a case where an acquaintance miswired a diesel excavator causing the consequent damage to the alternator.
Further it is trite practice that when any welding is carried out, even on the bucket of an excavator the first rule of practice is to disconnect the battery terminals and the alternator terminals before commencing the welding. In this case, in my view, the arcing caused by the spanner coming into contact with the alternator terminals causing the sparks is the equivalent to miswiring the battery.

 

[panason1c]

...."a spanner got caught between the terminal of the alternator and the bulkhead "...


I think it unlikely that the alternator is damaged.......... even though the live wire was connected to the alternator the 'short' was between the live and directly to earth via the bulkhead....and not through the alternator as it was not 'in circuit'.

Take Blackc55's advice and look for a (large) blown fuse.

 

[mattkh]

Further it is trite practice that when any welding is carried out, even on the bucket of an excavator the first rule of practice is to disconnect the battery terminals and the alternator terminals before commencing the welding.

Hi
Thanks I have learnt today. I only heard about the battery terminal.

 

[Aussie Nick]

Thats ok Matt . I am glad someone has got something out of the discussion.
The Panasonic/Television, view, inter alia, is that it must be a fuse related problem. In particular Panasonic's assertion :

"even though the live wire was connected to the alternator the 'short' was between the live and directly to earth via the bulkhead....and not through the alternator as it was not 'in circuit'." was the last remark on the issue.

I would respectfully assert that this suggestion in my view is in error. If the positive live terminal of the alternator is brought into contact with the bulkhead then the alternator positive terminal is in circuit with the negative terminal of the battery which is connected to the bulkhead.The net effect, in my submission, is that this activity has been known to cause damage to alternators through cold hard experience.

I understand that member Black has suggested that there may be a fuse under the carpet. I do not believe that the manufacturer would place a fuse in such an inaccessible place, especially where being in close proximity to flammable substances, such as the carpet and underlay, this may cause the occurrence of ignition by virtue of the failure of the fuse. I am not saying this is probable, as the function of the failure of the fuse is to ensure that the overheating feed wire does not continue to overheat. However, for political reasons, I do not believe that the manufacturer would locate a fuse under the carpet.

If there is a failed Fuse it is in the order of 40 amps and located in the engine compartment.

I do not know exactly who is right or wrong here but certainly, I think the debate is valuable for anyone tinkering with the battery and the electrical systems. Most certainly it is priceless to anyone contemplating welding some Tigerteeth to their Excavator bucket ( Four in One, of course ) and no doubt there are countless members here who fall into that category.

Incidentally, I know of a Chevrolette Mercruiser which totally survived a very short miswire of the battery.The miswire breaking only the radio fuse but in that case there were no sparks . The positive terminal wire did get a mite hot though.

 

[sl63amg]

Confused, what exactly is the fault? does the engine now start? if so what is the battery charging at, you can check this by putting the ignition on position 1 press the reset button on the cluster 3 times very quickly,start the engine and the cluser will display battery voltage, should be at least 13.4 volts after a few moments.If it is the alternator and the alternator is a bosch unit you can replace the electric pack on the back seperatly

 

[robm255]

The engine starts fine but there is no increase in voltage across the battery (currently readind 11.97 volts) when engine ticking over indicating a alternator problem. I have looked under thye carpet as suggested but there is no fuse and i have checked all the fuses in the engine bay and non have blown.

I have also had a ohm meter from the terminal at the back of the alternator to the positive of the battery and got no reading indicating an open circuit

 

[robm255]

Its Fixed !!!!!

finally found the fuse its in the wiring loom and you cant replace it !!! mercede's can do it for you for £1000 + vat + fitting !!!
I have bridged it with a new piece of cable and fitted a 80amp fuse and the car is now working perfectly thanks for your help guys

 

[panason1c]

Glad you got it sorted...Spot on diagnosis by blackC55.........