Lenze i700 User Manual

Lenze · i700 servo inverter · reference manual · DMS 3.0 EN · 06/2016 · TD06 164
5 Motor control & motor settings
5.16 "Short-circuit braking" function
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5.16 "Short-circuit braking" function
The control modes for synchronous motors provide the opportunity to use "short-circuit braking" for
the braking process.
Short-circuit braking can be
• parameterised via bit 6 in the Lenze control word (0x2830
or 0x3030 for axis B) or
• as response to light errors. Response of the device in the event of an error
( 279)
Cases of application
• for short-circuit braking via bit 6:
• The braking energy cannot be converted into heat in a brake resistor.
• An external control wants to request short-circuit braking as e.g. an error has been detected
in the encoder system which does not permit braking via quick stop.
• for short-circuit braking as response to light errors:
• Due to an encoder error, no quick stop is possible anymore.
Functional description
The effect of the short-circuit braking on the deceleration behaviour depends on the motor features,
the effective cable length, the mass inertia and the initial value of the speed (application point).
Primarily, short-circuit braking can be used to convert a part of the kinetic energy into heat energy
which serves to unload external brake assemblies and limit position dampers.
 Stop!
In some constellations, it is not possible to decelerate the motor speed of a synchronous
motor to zero by means of "short-circuit braking". The braking effect cannot be
compared to the "quick stop" function where the motor is energised under optimal
conditions!
 Note!
The short-circuit current is set freely according to the motor voltage (k
E
* speed) and the
internal resistance of the system. Thus, it is mandatory that the ampacity of the i700
servo inverter is oriented towards the short-circuit current to be maximally expected.
Guide value: I
max_device
(3 s) ≥ 1.5 * I
max_motor
(according to the data sheet/catalogue)
In case of a deviating assignment, a rating based on the currently possible parameters
(max. speed, max. motor current, field weakening, etc.) is required!

Lenze i700 Specifications

General

Control Type	Vector control, V/f control
Safety	STO (Safe Torque Off)
Protection Class	IP20
Frequency	50/60 Hz
Communication Interfaces	CANopen
Cooling	Air cooled
Protection Features	Overvoltage, Undervoltage
Ambient Temperature	-10°C to +45°C
Frequency Range	0 Hz to 300 Hz
Supply Voltage	3-phase AC