MGM BA Serie Empleo Y Mantenimiento página 8

The operations which must be carried out periodically in order to ensure the correct functioning of the MGM brake motor
are listed further on. The frequency of inspection depends on the particular motor duty ( number of start/stop, applied
moment of inertia, environment conditions and so on). Generally it's advisable to proceed to the first inspection
after few weeks of working and to draw up a periodical maintenance plan. Anyway it's recommended to provide
inspections at least twice a year. For specific information pls contact the M.G.M. motori elettrici S.p.A.
organization.
- Periodically check that the motor operates correctly without noise or strange vibrations and that the openings for
ventilation are not obstructed.
- Verify that all motor and brake supply terminals are property tightened to the terminal board as well as the earthing
terminal to the motor frame.
- As a result of normal wear of the brake disc lining, check that the air gap does not exceed the values shown on
table 1. The airgap must be as indicated on the table. Don't exceed this range to avoid any damage on the brake
assembly. Please note that the brake linings wear is greater during the run-in. ( few thousands stops). For the air gap
adjustment, follow the instructions given into the paragraph "Air Gap Adjustment".
- Check the wear on both friction surfaces of the brake disc (on one side only for BAPV series) to be sure that
their thickness is not less than 2 mm. Verify also that there are no damages on disc surfaces and, in particular, in the
hub toothing. (For replacement, refer to the paragraph "Brake Disc Replacement"). Moreover check that no play should
be between the brake disc and the brake disc hub in correspondence of the hub nails.
- Verify periodically that the braking torque is suitable. If needed, proceed to its adjustment as stated in the paragraph
"Braking torque adjustment".
- Verify regularly the brake adjuster (19-42) wear conditions and their steady fastening on the rear cover brake surface
(17).
- All brake assembly components, in particular the brake disc (23, 39-41 for BAF series, 45 for BAPV) and the
brake adjusters (19, 42 for BAF-BAPV series) are subject to wear. In consideration of the motor safety role, it's
needed to replace them periodically. The replacement frequency comes from the motor duty (number of
start/stop, applied moment of inertia, environment conditions and so on), we recommend however to replace
them at least every 18 months.
- Periodically check and verify the shaft splines wear, exactly where the disc slides. If the shaft splines has a
visible wear it's necessary to replace the rotor shaft (1).
Braking Torque Adjustment
The brake torque is proportional to the springs (18) compression, which can be varied by operating on the locknuts (20).
The compression of the springs must be as uniform as possible. On the table 2 and 3 the standard compression values
(H std) of the brake springs are shown. The corresponding brake torque of the standard compression values stated on
the table are less than the maximum braking torque stated on the motor nameplate, especially for AC brake assembly.
Please verify that the braking torque is suitable for your application.
If the brake coil (25) isn't able to call the brake moving element (24) back with a quick stroke and keep it attracted without
vibrations, verify the exact air gap adjustment and, if this inconvenience still persists, loosen the locknut (20) and try it
again until desired functioning is obtained.
Some types of motors ( BA series 160÷225) can have 3 or 6 springs(18). Pay attention to the different adjustment of the
spring compression to reach the brake torque value required.
After every intervention pls verify that the braking torque is the one required..
Never exceed the maximum braking torque value stated on the motor name plate. It's recommended to avoid adjusting
the braking torque to values lower than 40% of the maximum value. For any clarifications, please contact the M.G.M.
motori elettrici S.p.A. organization.
Brake Disc Replacement
Please verify that the type of brake disc is suitable for the application and in particular verify if it's need to be used a K
brake disc (e.g. liftings, safety applications, cranes and so on). For further details pls contact MGM motori elettrici SpA.
Loosen the rear nut (27), remove the end cover (26) and unscrew the locknuts (22). Take off the brake coil (25) from the
brake adjusters (19 o 42), remove the nuts (20-21) and the springs (18). Remove the brake moving element (24) sliding
it through the brake adjusters (19 o 42). Take off the old brake disc (23) and put in the new one.Verify that the new brake
disc is properly inserted in the correct way. For re-assembling, proceed backwards. The new brake disc must be