B&R 8LS 3 Series, Руководство пользователя

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Installation conditions
268 8LS...-3 user's manual V2.50
The following points must be observed:
• The opposite side of the mounting flange is not permitted to be thermally insulated. Heat from the motor
must be allowed to dissipate sufficiently.
•
Air circulation must not be impeded. There must be sufficient cooling air on the motor housing.
• Exceeding the specified maximum values for motor temperature is not permitted.
It is important to note the following:
• Power or heat from the motors is dissipated via the mounting flange and surface of the motor housing.
• The motor can heat up due to external heat sources.
Caution!
Personal injury and damage to property due to failure or overheating of the drive.
If the maximum permissible operating temperature is exceeded, a drive defect with consequential dam-
age is very probable.
The cause of a defect could insufficient lubrication due to overheating, for example.
•
For safety reasons, switch off the machine if the maximum permissible temperature is exceed-
ed.
•
Ensure unobstructed air circulation and cooling so that no heat accumulation can build up in
the drive or machine.
4.2 Load capacity of the shaft end and bearing
8LS three-phase synchronous motors are equipped with grooved ball bearings that are sealed on both sides and
lubricated. Radial and axial forces (F
r
, F
a
) applied to the shaft end during operation and installation must be within
the specifications listed below. Bearing elements are not permitted to be subjected to shocks or impacts! Incorrect
handling will reduce the service life and result in damage to the bearings.
Radial force
The radial force F
r
on the shaft end is a function of the loads during installation (e.g. belt tension on pulleys) and
operation (e.g. load torque on the pinion). The maximum radial force F
r
depends on the shaft end type, bearing
type, average speed, the position where the radial force is applied and the desired service life of the bearings.
Axial force, shift in shaft position caused by axial force
The axial force F
a
on the shaft end is a function of the loads during installation (e.g. stress caused by mounting)
and operation (e.g. thrust caused by slanted tooth pinions). The maximum axial force F
a
depends on the bearing
type and the desired service life of the bearings. The fixed bearing is secured on the B-side flange with a retaining
ring. The floating bearing on the B-side flange is preloaded with a spring in the direction of the A-side flange. Axial
forces in the direction of the B-side flange can cause the spring bias to be overcome, which shifts the shaft by
the amount of axial backlash in the bearing (approx. 0.1 - 0.2 mm). This shift can cause problems on motors with
holding brakes or all motors with inductive encoder systems. As a result, no axial force in excess of the calculated
values is permitted in the direction of the B-side flange when using these motors. (See "Determining permissible
values for F
r
and F
a
".)
Axial loads are not permitted on shaft ends of motors with holding brakes. It is especially important to prevent axial
forces in the direction of the B flange since these forces can cause the brake to fail!
Determining permissible values of F
r
and F
a
For information about determining permissible values of
Fr
and
Fa
, see th diagrams in chapter Technical data (section
"Maximum shaft load" for the respective motor).
The permissible values in the diagram are based on a mechanical bearing lifespan of 20,000 h (bearing lifespan
calculation based on DIN ISO 281).