torque (current) might be insufficient to holding the load at zero speed. When the STOP condition is present, the motor is ramping down to zero
speed (mechanical brake is still open), and at the set value (rpm) engages (closes down) the mechanical brake.
-
Par. 2-22
Activate Brake Speed [Hz]
. Linked to par. 2-21
Activate Brake Speed [RPM]
. Automatically adjusted according to the par. 2-21 value.
-
Par. 2-23
Activate Brake Delay
. The shaft is held at zero speed with full holding torque. This function ensures that the mechanical brake has
locked the load before the motor enters coast mode.
-
Par. 2-24
Stop Delay
. Allows successive starting without applying the mechanical brake (e.g., reversing).
-
Par. 2-25
Brake Release Time
. The time needed by the brake to be open/closed.
In closed-loop structure, the parameter dependency is:
-
Par. 5-40
Function Relay
or par. 5-41
On Delay, Relay
-
Par. 1-72
Start Function
: Hoist Mechanical Brake
-
Par. 2-25
Brake Release Time
-
Par. 2-26
Torque Ref
. Sets the torque to be applied against the closed mechanical brake before release.
-
Par. 2-27
Torque Ramp Time
-
Par. 2-28
Gain Boost Factor
. Compensates the “push back” when the speed controller takes over the torque controller.
9.1.9 Automatic Motor Adaptation (AMA)
AMA is an algorithm to measure the electrical motor parameters on a motor at standstill. This means thatAMA itself does not supply any torque.
AMA is useful when commissioning systems and optimizing the adjustment of the adjustable frequency drive to the applied motor. In particular, this
feature is used where the default setting does not apply to the connected motor.
par. 1-29
Automatic Motor Adaptation (AMA)
allows a choice of complete AMA with determination of all electrical motor parameters or reduced AMA with
determination of the stator resistance Rs only.
The duration of a total AMA varies from a few minutes on small motors to more than 15 minutes on large motors.
Limitations and preconditions:
•
For the AMA to determine the motor parameters optimally, enter the correct motor nameplate data in par. 1-20
Motor Power [kW]
to
par. 1-28
Motor Rotation Check
.
•
For the best adjustment of the adjustable frequency drive, carry out AMA on a cold motor. Repeated AMA runs may lead to a heating of the
motor, which results in an increase of the stator resistance, Rs. Normally, this is not critical.
•
AMA can only be carried out if the rated motor current is minimum 35% of the rated output current of the adjustable frequency drive. AMA can
be carried out on up to one oversize motor.
•
It is possible to carry out a reduced AMA test with a sine-wave filter installed. Avoid carrying out a complete AMA with a sine-wave filter. If an
overall setting is required, remove the sine-wave filter while running a total AMA. After completion of the AMA, reinsert the sine-wave filter.
•
If motors are coupled in parallel, use only reduced AMA if any.
•
Avoid running a complete AMA when using synchronous motors. If synchronous motors are applied, run a reduced AMA and manually set the
extended motor data. The AMA function does not apply to permanent magnet motors.
•
The adjustable frequency drive does not produce motor torque during an AMA. During an AMA, it is imperative that the application does not
force the motor shaft to run, which is known to happen with, e.g., wind milling in ventilation systems. This disturbs the AMA function.
9.1.10 Smart Logic Control Programming
A new useful facility in AutomationDrive FC 300 is the Smart Logic Control (SLC).
In applications where a PLC is generating a simple sequence, the SLC may take over elementary tasks from the main control.
SLC is designed to act from event sent to or generated in the adjustable frequency drive. The adjustable frequency drive will then perform the pre-
programmed action.
FC 300 Design Guide
9 Application Examples
MG.33.BC.22 - VLT
®
is a registered Danfoss trademark
9-5
9