Motor Selection, Position/Speed Sensing; Motor Selection; Motor Protection; Motors With Holding Brake - Siemens SIMODRIVE 611 Planning Manual

Motor Selection, Position/Speed Sensing

3.1

Motor selection

The motor should be selected according to the mechanical and dynamic
response characteristics which it must fulfill. The motor overload capability
required depends on the magnitude and number of load peaks during the
operating time.
3.1.1

Motor protection

Motor protection circuit–breakers should be used to protect the motors which
only switch a signal contact when the motor is overloaded.
If the motor is isolated from the power module during operation with the drive
pulses enabled, there is a danger that the power module and control module
could be destroyed.
3.1.2

Motors with holding brake

Description The holding brakes mounted onto the motors are used to brake the motor at
standstill. It can also shorten the braking travel under emergency conditions.
However, the holding brake is not an operating brake.
Note
The motor holding brakes may only be actuated when the motor is at a stand-
still.
If the holding brake is actuated during operation or while the motor is rotating,
this results in increased wear and shortens the lifetime of the holding brake.
This means that holding brake failure must be taken into account when
engineering the drive system and a hazard analysis must be carried out.
Hanging loads
If holding brakes are used for hanging loads, this must be carefully analyzed as
there is a high potential danger.
Monitoring
By traversing to a defined endstop, a reference quantity is obtained to monitor
the braking travel. The measured braking travel is an indication of the brake
wear.
 Siemens AG 2001 All rights reserved
SIMODRIVE 611 Planning Guide (PJU) – 05.01 Edition
3
3
3-55