Flange Protection Removing; Insulation Resistance; Safety Instructions; General Considerations - WEG AG10 Serie Manual De Instalación, Operación Y Mantenimiento

4.4.1

Flange protection removing

1
Figure 4.3: Flange protection
Figure 4.3 legend
1. Flange
2. Flange protection
3. Grille
4. Screw
5. Clamp
ATTENTION
The protection (2) between the ventilation grille
(3) and the flange (1) is an integral part of the
package and must be removed when
installing the alternator, so as not to impair the
cooling during the operation. See the
procedure as follow:

Cut the clamps (5) that secure the
protection grille;

Remove the grille and flange protection;

Reinstall the ventilation grille, securing it
with the screws (4).

4.5 INSULATION RESISTANCE

4.5.1

Safety instructions

DANGER
To make the measurement of insulation
resistance, the alternator must be stopped and
unplugged from the load and the voltage
regulator unplugged.
The winding being tested must be connected
to the frame and ground for a period until
removing the residual electrostatic charge.
Failure to follow these procedures may result
in personal injury.
4.5.2

General considerations

When the alternator is not immediately placed into
operation, it must be protected against moisture, dirt and
high temperature, thus avoiding that the insulation
resistance
The insulation resistance of the windings must be
measured before entry into operation.
If the environment is too humid, it is necessary to check it
periodically during storage. It is difficult to determine rules
for the real value of insulation resistance of a machine,
since it varies with environmental conditions (temperature,
humidity), conditions of machine cleaning (dust, oil,
12638144 Installation, operation and maintenance manual – Synchronous Alternator – AG10 line - Horizontal l 23
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grease, dirt) and quality and conditions the insulating
material used.
The evaluation of the periodic monitoring records is useful
to conclude whether the generator is able to operate.
NOTE
The insulation resistance must be measured
using a MEGOHMMETER.
4.5.3

Measurement of the stator winding

The test voltage to the stator windings of the alternators
must be as Table 4.1 in accordance with standard IEEE43.
Table 4.1: Voltage for measurement of the insulation resistance
Winding nominal
voltage (V)
< 1000
1000 - 2500
2501 - 5000
5001 - 12000
> 12000
NOTE
The insulation resistance readings are taken
after the test direct voltage is applied for 1
minute.
Before measuring the stator winding, check:

If all load cables are disconnected;

If the voltage regulator is disconnected;

If the frame of the alternator and the windings not
measured are grounded;
 If the temperature of the winding has been measured;

If all temperature sensors are grounded;
The measurement of the insulation resistance of the stator
windings must be made in the main terminal box.
The meter (megohmmeter) must be connected between
the frame of the alternator and the winding. The frame
must be grounded and the three phases of the stator
winding remain connected to the neutral point, as shown
Figure 4.4.
Figure 4.4: Measurement in the three phases
Whenever possible each phase must be insulated and
tested separately. The separate test allows the
comparison between the phases. When a phase is tested,
the other two phases must be grounded on the same
grounding of the frame, as shown Figure 4.5.
Figure 4.5: Measurement in separate phases
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Insulation resistance test
continuous voltage (V)
500
500 -1000
1000 - 2500
2500 - 5000
5000 - 10000
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