Safety Precautions - Siemens BG 71 Serie Instrucciones

In the case of converter-fed motors, high-frequency current or voltage
harmonics in the motor cables can give rise to electromagnetic interference.
That is why the use of shielded cables is recommended.
Before commissioning, check that:
- The minimum insulation resistances are adhered to
- The rotor turns freely without rubbing
- The motor is properly assembled and aligned
- The transmission elements are correctly adjusted (e.g. belt tension) and
the transmission element is suitable for the given operating conditions
- All electrical connections, mounting screws and connecting elements
are properly tightened and fitted
- All protective conductors are properly installed
- Any auxiliaries that may be fitted (brakes) are in working order
- Touch protection guards are installed around moving and live parts
- The maximum speed n (see rating plate) is not exceeded.
max
NOTE: The maximum speed n
permitted for short periods. It should be kept in mind that motor noise and
vibration are worse at this speed, and bearing life is reduced.
It is not possible to formulate a complete check list. Other checks
may also be necessary!
3 Maintenance

Safety precautions

Before starting any work on the motor or
other equipment, particularly before opening
covers over live or moving parts, the motor
must be properly isolated from the power supply. Besides the
main circuits, any additional or auxiliary circuits that may be
present must also be isolated.
The usual "5 safety rules" (as set forth in DIN VDE 0105) are:
- Isolate the equipment
- Take effective measures to prevent reconnection
- Verify equipment is dead
- Earth and short-circuit
- Cover or fence off adjacent live parts
The precautions listed above should remain in force until all
maintenance work is finished and the motor has been fully
assembled.
Any repair work must be carried out in Siemens workshops or by
an officially appointed expert.
Grease change, type of grease
Under normal operating conditions, with horizontally mounted motors and
coolant temperatures of up to 40 °C, the grease should be changed at
intervals of:
• approx. 20,000 operating hours for speeds of 1500 rev/min
• approx. 10,000 operating hours for speeds of 3000 rev/min
Irrespective of the number of operating hours, the grease should be
renewed every 3 years because of ageing.
In the case of motors operating under special conditions, such as vertical
motor position, frequent operation at maximum speed n
sudden load changes and frequent reversing operation, the grease should
be changed at considerably more frequent intervals than at the operating
hours stated above.
Type of grease for standard machines: UNIREX N3 (Esso); synthetic
greases must conform to DIN 51825-K3N.
Special greases are indicated on the rating plate.
Avoid mixing different types of grease!
6
is the highest operating speed
max
, heavy vibration,
max
ENGLISH
Dismantle the motor to the extent necessary.
NOTE: Notice the cover plate arrangement when changing the bearings!
Pull off the rolling-contact bearings with a suitable device.
Clean the journal! Clean the bearings and pack with fresh grease.
Pack the bearing cavities flush with grease! The cover plate or endshield
is kept free of grease to prevent overgreasing.
Heat bearings evenly to about 80 °C and press on. Heavy blows (such as
with a hammer, ...) should be avoided.
Any worn sealing elements (such as shaft sealing ring, etc.) should also
be renewed.
If springless radial shaft sealing rings are used, the replacement sealing
rings must also be of the springless type.
The areas next to flameproof gaps, e.g. at the locating edges and the shaft
gland, must not be altered.
Regreasing device
In the case of motors with regreasing device, take note of the information
given on the rating plate! During regreasing, the rotor should turn so that
the new grease is distributed in the bearings.
Plastic fans
For motors with frame sizes from 71 to 160L, the fans are axially attached
with a featherkey and a snap ring.
The fans of frame sizes 180M and 200L have a cast-on feather key and
two cast-on tabs which snap into the ring groove on the shaft to prevent
axial movement.
Before the fan is pulled off the shaft, these two tabs must be disengaged
and held temporarily in that position, e.g. by inserting packing. In the disc
at the root of the blades, there are two openings for the claws of an
extractor whose central screw should press against the hub. On delivery,
these openings may be covered by a film of plastic.
A suitable device should be used for pulling the fan off and pressing it back
on. Hammer blows must be avoided.
Siemens AG