Differences
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techtalk:ih:elec02a [2018/12/16 23:36] hippysmack |
techtalk:ih:elec02a [2018/12/16 23:47] hippysmack |
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| {{ :techtalk:ih:elec:generator_drawing_2_by_sifty.jpg?direct&400|}} | {{ :techtalk:ih:elec:generator_drawing_2_by_sifty.jpg?direct&400|}} | ||
| - | Field winding resistance: \\ | + | **Field winding resistance**: \\ |
| Placing the leads across the A and F terminals will give you the effective resistance of the field windings (2 windings in series). \\ | Placing the leads across the A and F terminals will give you the effective resistance of the field windings (2 windings in series). \\ | ||
| The armature circuit is not included as in a healthy generator there is no return path via ground to the meter. \\ | The armature circuit is not included as in a healthy generator there is no return path via ground to the meter. \\ | ||
| This should be around the 5.8 ohm mark, a higher figure indicates a possible open circuit, and a lower figure may mean a winding is shorting out somewhere. | This should be around the 5.8 ohm mark, a higher figure indicates a possible open circuit, and a lower figure may mean a winding is shorting out somewhere. | ||
| - | Armature resistance: \\ | + | **Armature resistance**: \\ |
| Placing one lead on a good, clean ground point on the case (shiny metal) and the other on the A terminal, will follow the path through the armature to ground. \\ | Placing one lead on a good, clean ground point on the case (shiny metal) and the other on the A terminal, will follow the path through the armature to ground. \\ | ||
| This should be very low, typically less than 0.6 ohms but can vary as it depends on the brush/commutator condition. | This should be very low, typically less than 0.6 ohms but can vary as it depends on the brush/commutator condition. | ||
| - | Total resistance: \\ | + | **Total resistance**: \\ |
| Placing the leads on a good ground point and the F terminal effectively measures the field plus armature circuits in series (from the F terminal, through the field windings, then through the armature to ground). \\ | Placing the leads on a good ground point and the F terminal effectively measures the field plus armature circuits in series (from the F terminal, through the field windings, then through the armature to ground). \\ | ||
| As a quick check, this result should be very close to the values of the previous tests added together. | As a quick check, this result should be very close to the values of the previous tests added together. | ||
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| {{ :techtalk:ih:elec:generator_drawing_3_by_sifty.jpg?direct&400|}} | {{ :techtalk:ih:elec:generator_drawing_3_by_sifty.jpg?direct&400|}} | ||
| With the brushes out there are a couple of further tests available: ((photo by sifty of the XLFORUM http://xlforum.net/forums/showthread.php?t=1592463&page=42)) \\ | With the brushes out there are a couple of further tests available: ((photo by sifty of the XLFORUM http://xlforum.net/forums/showthread.php?t=1592463&page=42)) \\ | ||
| - | Winding insulation: \\ | + | **Winding insulation**: \\ |
| Placing one lead on a clean ground point of the casing, and the other on either terminal (do both) should give a very high reading (ideally in the Mega-ohms range). \\ | Placing one lead on a clean ground point of the casing, and the other on either terminal (do both) should give a very high reading (ideally in the Mega-ohms range). \\ | ||
| This indicates the windings are not shorting to ground anywhere. | This indicates the windings are not shorting to ground anywhere. | ||
| - | Winding current: \\ | + | **Winding current**: \\ |
| Connecting the battery through the multimeter in the Amps scale should result in a DC current of around 2 amps. \\ | Connecting the battery through the multimeter in the Amps scale should result in a DC current of around 2 amps. \\ | ||
| Ohms law states V = IR, so with 12V and a resistance of around 6 ohms I = V/R which gives the 2 amps (will vary in practice as your winding resistance and battery voltage will differ). \\ | Ohms law states V = IR, so with 12V and a resistance of around 6 ohms I = V/R which gives the 2 amps (will vary in practice as your winding resistance and battery voltage will differ). \\ | ||
| - | Motor test: \\ | + | **Motor test**: \\ |
| This is probably the best indication, as a generator that will motor with voltage applied indicates all is well with the commutator / brush assembly. \\ | This is probably the best indication, as a generator that will motor with voltage applied indicates all is well with the commutator / brush assembly. \\ | ||
| Jumper leads from a good battery were used and a short piece of wire (applied +12V to the A terminal, and -12V to the case and F terminal simultaneously). \\ | Jumper leads from a good battery were used and a short piece of wire (applied +12V to the A terminal, and -12V to the case and F terminal simultaneously). \\ | ||
