Lenze DSD - Manual (Page 327)

Lenze · Drive Solution Designer · Manual · DMS 4.2 EN · 12/2013 · TD23
327
11 Drive Dimensioning
11.3 Mechanical brake selection
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11.3.1 Spring-applied brake (BFK)
Three-phase AC motors can be equipped with a spring-applied brake. After switching off the supply
voltage, the spring-applied brake is activated (closed-circuit principle). For an ideal adaptation to
the application, several braking torques and control variants are available for every motor frame
size. Brakes in the long-life design are equipped with stronger brake mechanics and are suitable for
applications with very high operating frequencies.
The very short operating times of the brake are realised through DC switching of the voltage. For in-
terference suppression purposes, a spark suppressor is required which also increases the service life
of the relay contacts.
• Asynchronous servo motors of the MQA series can be configured with spring-applied brakes of
the BFK460/BFK458 series.
• For each motor frame size, two brakes of different frame sizes can be selected (this option is
generally possible but not in every case).
• Three-phase AC motors can be configured with spring-applied brakes of the BFK458 series.
• For each motor frame size, two brakes of different frame sizes can be selected (this option is
generally possible but not in every case).
11.3.2 Permanent magnet holding brake (PMB)
Permanent magnet holding brakes are backlash-free and can also hold the deenergised drive at a
defined position. After switching off the supply voltage, the permanent magnet holding brake is ac-
tivated (closed-circuit principle).
The very short operating times of the brake are realised through DC switching of the voltage. For in-
terference suppression purposes, a spark suppressor is required which also increases the service life
of the relay contacts.
Surface-ventilated servo motors (IP 54) are equipped with permanent magnet holding brakes.
• For motors of the MCS series two types of brakes (in the case of MCS 06/19 only one type) with
different frame sizes are offered to be able to provide the required braking torque for different
applications.
• For motors of the MCA series only one frame size per motor is offered.
• If the safety factor must be increased for e.g. a hoist drive, a bigger motor can be selected to be
able to mount a bigger brake.
Features
Design
• Standard: 1 × 10 6 switching cycles, repeating
1 × 10 6 switching cycles, reversing
• Long-life: 10 × 10 6 switching cycles, repeating
15 × 10 6 switching cycles, reversing
Control • DC supply
• AC supply via rectifier in the terminal box
Enclosure • Without manual release IP 55
• With manual release IP 54
Friction lining • Asbestos-free, with low rate of wear
Options • Manual release
• UL/CSA-approved
• Low noise