WEG S Series - Re-Impregnation; Insulation Resistance; Cooling System Maintenance; Radiator Maintenance

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40 l Installation, Operation and Maintenance Manual – Synchronous Motors – S Line – Brushless – Horizontal 11866576
7.4.2 Re-impregnation
If any layer of resin on the windings is damaged during
cleaning or inspection, such parts must be corrected with
adequate material (in this case, consult WEG).
7.4.3 Insulation resistance
The insulation resistance must be measured after the
completion of all of the maintenance procedures.
A
TTENTION
Before putting the motor back into operation,
it is essential to measure the winding
insulation resistance and ensure that the
measured values meet the specifications.
7.5 COOLING SYSTEM
MAINTENANCE
 The pipes of the air-air heat exchanger (if any) must be
kept clean and unobstructed to ensure a perfect heat
exchange. In order to remove the dirt accumulated in
the pipes, a rod with a round brush on the tip may be
used.
 In case of air-water heat exchangers, periodic cleaning
in the radiator pipes is necessary to remove all and any
incrustation.
NOTE
If the motor has filters in the air inlets and/or
outlets, they must be cleaned with
compressed air.
If the dust is difficult to remove, wash the
filters with cold water and neutral detergent
and dry them in the horizontal position;
In case the filters are impregnated with dust
containing grease, it is necessary to wash
them with gasoline, kerosene or another
petroleum solvent or hot water with P3
additive;
A
ll the filters must be dried after the cleaning.
Do not twist them;
Replace the filter if necessary.
7.6 RADIATOR MAINTENANCE
The degree of dirt in the radiator can be detected by the
increase of the temperature at the air outlet. When the
temperature of the cold air, under the same operating
conditions, exceeds the specified value, it can be
assumed that the pipes are dirty.
If corrosion is found in the radiator, it is necessary to
provide adequate protection (i.e., zinc anodes, cover with
plastic, epoxy or other similar products) in order to prevent
further damage to the parts already affected.
The external surface of all the radiator parts must be
always kept in good conditions.
Instructions for removal and maintenance of the
radiator
In order to remove the radiator for maintenance, use the
following procedure:
1. Close all the water inlet and outlet valves after stopping
the ventilation;
2. Drain the water through the radiator drain plugs;
3. Remove the heads, keeping the bolts, nuts, washers
and seals (gaskets) in a safe place;
4. Brush the inside of the pipes carefully with nylon
brushes in order to remove residues. If damages to the
radiator tubes are found during the cleaning, they must
be repaired;
5. Reassemble the heads, replacing the gaskets, if
necessary.
7.7 VIBRATION
Any evidence of increase in the unbalance or vibration of
the motor must be investigated immediately.
7.8 SHAFT GROUNDING DEVICE
The shaft grounding brush (if any) avoids the circulation of
electric current through the bearings, which is detrimental
to their operation. The brush is put in contact with the
shaft and connected by a cable to the motor frame, which
must be grounded. Make sure that the brush holder
fastening and its connection to the frame have been made
correctly.
Figure 7.1: Shaft grounding brush
Drying oil is used to protect the motor shaft against rust
during transportation. In order to ensure the proper
operation of the grounding brush, this oil, as well as any
residue between the shaft and the brush, must be
removed before starting the motor. The brush must be
constantly monitored during operation, and it must be
replaced by another one of the same quality (granulation)
at the end of its useful life.
7.9 EXCITER MAINTENANCE
7.9.1 Exciter
For the good performance of its components, the motor
exciter compartment must be kept clean. Perform periodic
cleaning in the windings following the procedures
described in section 7.2 of this manual.
7.9.2 Insulation resistance
Check the insulation resistance of the main and auxiliary
exciter windings periodically in order to determine their
insulation conditions, following the procedures described
in section 4.4.4 of this manual.
7.9.3 Diode test
Diodes are components that have great durability and do
not require frequent tests. If the motor presents any defect
indicating diode failure through the voltage regulator or an
increase in the field current for the same load condition,
then the diodes must be tested according to the following
procedure:
Shaft