Bosch DOK-MOTOR-MCL Series, Project Planning Manual

Page: 79 / 196

7 Accessories and options
7.1 Hall unit
7.1.1 General information
To drive synchronous motors, an absolute position information regarding pole
pair or pole pair width is necessary to recognize the position of the perma‐
nent magnets to the motor windings. Only in connection with an electric com‐
mutation offset angle, which must be determined at initial start-up, it is possi‐
ble to impress the voltage with correct phase position to the magnetic field via
the controller so that the motor can develop its force.
When using an incremental length measuring system, a commutation of the
axes has to result from every step up of the phases of the drive device. This
is done by a drive-internal procedure. After this, a force processing of the mo‐
tor is possible.
The commutation is determined automatically during the phase
step up by the Hall unit. Therefore, no power switch-on (no motor
movement) is necessary.
The Hall unit offers special advantages, for example at commutation of linear
motors ...
●
in Gantry arrangement,
● on vertical axes,
● in mechanical safe state,
● which are not allowed to be driven during the commutation process for
safety reasons.
7.1.2 Hall unit functional princple
The Hall unit (analog or digital) serves for motionless commutation of ironless
linear motors in connection with an incremental measuring system. On
IndraDrive Cs, the motor is automatically commutated from phase switch into
operating mode. Therefore, no power motion is necessary. The motor can be
stalled, for example, or be at the travel length end (end stop).
Rexroth linear motors of MCL020 ... 070 series can be ordered with or with‐
out Hall unit (see chapter 6.1.2 "Type code primary part MCP" on page 63 )
according to the motor type code.
Independend from the origin order design, the primary parts of
020 ... 070 series can be upgraded or modified with a Hall unit
which can be ordered separately.
DOK-MOTOR*-MCL********-PR05-EN-P Bosch Rexroth AG 77/193
Rexroth IndraDyn L Ironless Linear Motors MCL
Accessories and options