Page 33
Drying with External Heat:
Place heat lamps, space heaters (in
addition to the ones already supplied) or a steam pipe near the
windings. Monitor winding temperatures. Raise winding temperature
gradual ly at a rate of 50° F (28° C) per hour up to 200° F (93° C).
Measure insulation resistance at 1-hour intervals. Typically the
insulation resistance will slowly drop while the temperature is coming
up, and then gradual ly increase and level out.
Drying with AC Current in the Armature:
Short circuit the generator
terminals. Provide DC excitation to the brushless exciter field winding.
Insert a current transformer and an ammeter to read full load current.
Run the generator at rated speed. Apply excitation to the exciter field
until rated current is developed. Monitor winding temperatures until
they stabilize. Continue running until insulation resistance values
level off. Monitor winding temperatures. Raise winding temperature
gradually at a rate of 50° F (28° C) per hour up to 200° F (93° C).
Measure insulation resistance at 1-hour intervals. Typically, the
insulation resistance will slowly drop while the temperature is coming
up and then gradually increase and level out.
Bearing Lubrication
Sleeve Bearings:
Lubricate the bearings in accordance with the
lubricating instructions attached to the generator and the bearing
lubrication instructions, which are provided in the manual package as
supplementary material.
Roller Bearings:
In applications where regreaseable bearings are used,
grease fill fittings and relief valves are incorporated into the bearing
housing. Lubricate the bearings in accordance with the lubricating
instructions attached to the generator.
Rectifier Tests
If a failure of a rectifier is suspected, remove the exciter cover. Remove
the nut and washer holding the rectifier in the heat sink, and remove
the diode lead wire. Lift the rectifier from the heat sink (see Figure
18 for an overview). Test the entire rectifier with an ohmmeter or test
lamp as follows:
Figure 18
Rectifier
Ohmmeter:
Connect the ohmmeter leads across the rectifier in one
direction. See Figure 19. Note the meter reading. Reverse the leads,
and note the meter reading. The meter should indicate a low resistance
when the leads are across the rectifier in one direction and a high
resistance when the leads are across the rectifier in the opposite
Negative
Positive
Positive
NOTE:
For specific lubrication instructions,
always refer to the bearing lubrication
sheet that came with your manual or the
lube plate on the generator.
Содержание 4P10
Страница 8: ...Page 8...