Pilz PMCtendo SZ.41/0/1/2/7/K/H/60/00 - Manual (Page 16)

Operating Manual PMCtendo SZ 
1002405-EN-03
16
3 Description
As the servo motors can be quickly and actively braked by appropriate setpoint settings
at the servo amplifier, the built-in brakes function as a holding brake. Additional brakes
must be provided for braking when the motor is turning, e.g. for an emergency stop.
3.8.2 Brake test and grinding
If a brake does not perform any friction work over an extended period of time, its friction
factor may change due to accumulations of flash rust or vapors resulting from high motor
temperatures. It is also possible that a slight material distortion may be noted as the re-
sult of major temperature fluctuations.
To ensure the functional safety of brakes, including the case of gravity-loaded vertical ax-
es, the brakes must be subjected to brake tests at regular intervals.
Testing brakes
Load the brake with 1.3 times the load torque. Make certain that the suspended load of
a vertical axis is already exerting torque on the motor when it is at a standstill.
Regrind the brake
If the tested braking torque differs from the required value, a brake can be reground.
To do this, run the motor at maximum 20 rpm.
Release and close the brake once per second so that the motor is required to work
against the closed brake for about 0.7 seconds.
Repeat these steps in the reverse direction of rotation after about 20 cycles. If the nom-
inal holding torque of the brake is still not correct after this regrinding, repeat the entire
process. If the nominal holding torque of the brake has still not been reestablished after
grinding five times, check for other factors that could be responsible for the deviating
nominal holding torque of the brake, for example if the wear limit has been reached.
Depending on the relevant servo inverter types, the grinding routine can also be auto-
mated. For further details see the corresponding documentation.
3.9 Motor shaft and bearings
The servo motors have a smooth shaft end (DIN 6885) on the drive side. With a friction
connection, torque transfer must be achieved through surface pressure. This guarantees
a safe, backlash-free force transfer.
The bearings are designed as ball bearings with permanent lubrication and non-contact
seals.