WEG M line Series, Инструкция по установке, эксплуатации и обслуживанию

Страница: 36 / 59

www.weg.net
36 l
Installation, operation and maintenance manual – Squirrel cage motor – M line – Vertical 11371757
6.3.5 Vibration
The motors are balanced at the factory in compliance
with the vibration limits established by IEC60034-14,
NEMA MG1 – Part 7 and NBR 11390 standards (except
when the purchase contract specifies different values).
The vibration measurements are carried out on the NDE
and DE bearings, in the vertical, horizontal and axial
directions. When the customer sends the half coupling to
WEG, the motor is balanced with the half coupling
mounted on the shaft. Otherwise, according to the
standards above, the motor is balanced with half-key
(i.e., the key slot is filled with a bar of the same width,
thickness and height of the key slot during the balancing
operation).
The maximum vibration levels attended by WEG for
motors in operation are informed in Table 6.1. These
values are generic and for guidance, and the specific
application conditions must always be taken into
account:
Table 6.1: Vibration (RMS)
Rated speed
(rpm)
Vibration Levels (mm/s RMS)
Frame < 355 355 to 560 > 630
600 ≤ n ≤ 1800
Alarm 4.5 4.5 5.5
Tripping 7.0 7.0 8.0
1800 < n ≤ 3600
Alarm 3.5 4.5 5.5
Tripping 5.5 6.5 7.5
The main vibration causes are:
Misalignment between the motor and the driven
equipment;
Improper fastening of the motor to the base, with
“loose shims
” under one or more motor feet, and
loose fastening bolts;
Improper or insufficiently rigid base;
External vibrations proceeding from other equipment.
ATTENTION
Operating the motor with vibration levels
above the values contained in Table 6.1 may
impair its useful life and/or performance.
6.3.6 Shaft vibration limits
In motors equipped with or prepared for the installation of
proximity sensors (normally used on sleeve bearings), the
surfaces of the shaft are prepared with special finishing in
the areas adjacent to the bearings, in order to assure the
correct measurement of the shaft vibration.
The shaft vibration measured in these motors must
comply with the IEC 60034-14 or NEMA MG 1 standard.
The alarm and trip values of Table 6.2 represent the
acceptable shaft vibration values for coupled electrical
machines according to the ISO7919-3 standard.
These values are generic and for guidance, and the
specific application conditions must always be taken into
account, especially the diametrical clearance between the
shaft and the bearing.
Table 6.2: Shaft vibration
Rated Speed
(rpm)
Shaft Vibration (μm peak-to-peak)
Frame
280 and
315
355 to
450
> 450
1800
Alarm 110 130 150
Tripping 140 160 190
3600
Alarm 85 100 120
Tripping 100 120 150
ATTENTION
Operating the motor with shaft vibration
values within the alarm or tripping range may
cause damages to the bearing shell.
The main causes for increase in shaft vibration are:
Coupling unbalance issues or other problems that may
also generate machine vibration;
Shaft shape problems in the measurement region,
minimized during manufacturing;
Residual magnetism or voltage on the shaft surface
where the measurement is done;
Scratches, dents or variations on the shaft finishing in
the measurement region.
6.3.7 Shutdown
In order to shut down the motor, proceed as follows:
Reduce the load of the driven equipment, if possible;
Open the main circuit breaker;
Switch on the high-pressure oil injection system (if
any);
After the motor stops completely:
Switch off the high-pressure oil injection system (if
any);
Switch off the oil circulation system of the bearings (if
any);
Switch off the hydraulic unit (if any);
Shut down the industrial water system (if any);
Switch off the forced ventilation system (if any);
Switch on the space heaters. They must be kept ON
until the next motor operation.
DANGER
Even after switching the motor off, while the
rotor is rotating, there is danger to life by
touching any of the motor active parts.
ATTENTION
The terminal boxes of motors equipped with
capacitors must not be opened before their
full discharge.
Discharge time of the capacitors: five
minutes after shutting down the motor.