Examen De Fin Module Courant Alternatif Électromécanique des Systèmes Automatisées-ESA-OFPPT-PDF
Examen De Fin Module Courant Alternatif
Plan to replace the obsessional screws, cable glands of the cable entries in the terminal block plate.
Provide a box for storing small parts.
When disassembling, mark the shims intended to align the motor General control of an engine
Check for visible damage:
- Deteriorated collector: furrow at the location of the brushes, heating follow-up, brush deposits.
- Deformed or detached fan cover;
- Cracked obsession legs or damaged obsession lady of the hour.
- No accumulation of dust, filaments, shavings and other materials on the carcass or around the fan inlet
- No significant consumption on the lifting eye rings / bolts
- No excessive vibrations
- No loose fasteners
- Cables and earths in good condition
- Motor tightness and cable gland in good condition
- Adequate insulation resistance. It is important to carry out this check after an extended shutdown period.
- Possible lubrication, particularly for 2-pole motors (3000TM) of high power.
- General condition of the engine, child alignment and its transmission components (pulley, pinion, chain, belt).
- Standard wear thermal weakness of the winding wires, especially on the elbows. This thermal weakness occurs after ten years of use in discontinuous administration following expansion and retraction under the effect of thermal varieties.
Run the engine empty with the fundamental and check the absence of abnormal braking for small models.
Standard rotor control of the manifold slats
The two test probes are affixed to the ohmmeter:
· On two close lamellae: a resistance of a few 1/10 ohms must be measured, carry out this check on each pair of lamellae by rotating the rotor at the fundamental.
· On two opposite strips: a few ohms must be measured. This value must decrease when the measurement is made on strips from in addition to in addition to close together.
A rotor winding cut can be due to a bad weld at the connection of the lamella with the winding wire. A solder can be apparently perfect but mask a pocket of resin or insulating oxide which surrounds the copper of the wire.
Demagnetization of rotor magnets (lasting magnet)
It may happen that a magnet loses its magnetic properties. It must then be replaced.
Brooms and brush springs (formerly carbon brushes)
Do not hesitate to regularly change the brushes as soon as they decrease significantly in volume or turn blue. A broom must be checked every 1000 hours. The length of the brushes must not fall under the effect of wear below 1/3 of its initial length. On some brushes a mark indicates the level of wear. The brushes are always changed by full set.
In preventive maintenance, it is necessary to check that the edges of the child brooms free from chipping, from burns, signs of abnormal wear.
The pressure of the brush holder springs must be 160 to 200 g / cm2
The springs must be checked and changed every 3 or 4 brush exchanges every two years. Standard strong temperature points show it that the springs lose their hardness.
Each time the brush is replaced, the brushes must be run in to form the collector.
1. Place the broom in child housing
2. Sandpaper the rough part facing the broom to be shaped
3. Replace the brush holder springs to ensure pressure of the brush on the abrasive
4. Go back and forth with the sandpaper
5. Check the shape of the broom
6. Pass a blow gun upset (compressed air)
7. Proceed with reassembly
Dynamic running-in of the brushes must then be carried out at 1500 visits / min for at least 3 hours by supplying the motor with a reduced reduced pressure so that it does not run out. A CC soldering station can very well be used.
It must be checked at each visit and cleaned if any brooms have left black follows. Do not use rough cloth leaving conductive dust. Sandpaper does the job perfectly.
A dirty collector manifests itself by a trail of sparks during child operation.
If it shows signs of wear, disassemble the rotor and correct the manifold.
Collectors can be amended:
· On visit at 1500rpm most extreme. Pay attention to the centering which must be within 1 or 2/100 mm.
· On a wheel grinding machine with passes from 2 to 3/100 mm? take the same centering precautions as above.
· With abrasive stones mounted on the collector in place
After the amendment of the collector, it is especially necessary to scrape the spaces between the lamellae of the collector with a special tool. This precaution avoids:
- premature wear of the brushes
- the jumping of the brushes on these insulating slats which causes significant sparks and decreases the power of the motor while reducing child uptime
On the strength power collectors, it will not be necessary to scrape but rectify the bury of the lamella spaces with a milling machine to a depth of 1 to 1.5mm and chamfer the edges of the blades. The chamfer will be 2 mm at 45 °.