40
Technical Information
Commutation with a Sine Wave
Sine wave commutation means that the rotating
magnetic field is always ideally positioned to the
armature. This minimizes torque variance even
when the motor is rotating very slowly. The
motor is also very quiet.
Current Controller and Current Limiting
The 3564K024B C comes equipped with a
current controller which makes torque limiting
possible.
It is possible to program 2 values for current.
1.) Peak Current
ASCII Command: LPC8000
➔
Limits peak current
at 8000 mA
The current will be limited at this value as long
as the calculated thermal current model remains
noncritical.
2.) Continuous Current
ASCII Command: LCC2800
➔
Sets continuous
current to 2800 mA
If the thermal model goes critical the motor
will automatically switch from the peak to the
continuous current value.
Diagram 13: The I2t current limiting
Operating Mode of the Current Controller
When the power is turned on to the motor,
the current controller sends the value for peak
current as the command current value.
With increasing load the current will increase
until the peak current has been reached.
The current controller then limits the current
at the peak level.
An approximate thermal model is calculated
directly from the actual current through the
motor during operation. If the thermal model
rises above a critical value the controller will
automatically limit the current to the lower
continuous current value. The current limiting
will switch back to the peak value only after the
motor temperature has fallen below the critical
value. This protects the motor from overheating
but also allows for extreme loading over short
periods of time for extremely dynamic
applications.
