Danfoss VACON NX, Application Manual

Page: 308 / 360

-
0-2
3
4
No brake-off control
Brake-off ctrl, 2 limits
Brake-on/off crtl, 1 limit
0-2
3
4
No brake-off control
Brake-off ctrl,
torque limit
0-2
3-4
AND
OFF-
DELAY
COUNT
ON-
DELAY
COUNT
ID346
ID348
ID315
ID346
0-2
3
0-2
3
0-3
4
ID316
ID347
0-3
4
≤
3
4
Run state
No Run request
AND
OR
TRUE
f
out
≥ ID347
TRUE
Motor torque ≥ ID349
Brake-on ctrl, 2 limits
No brake-on control
Brake-on/off crtl, 1 limit
No brake-on control
OR
f
out
Fault
NOT
Reversing
No run request
OR
B
ra
ke
-o
ff
co
n
tr
o
l
B
ra
ke
-o
n
co
n
tr
o
l
Brake off
Brake on
e
3
0
b
h
0
8
5
.1
0
Illustration 98: Brake Control Logic
When using the Master Follower function, the follower drive opens the brake at the same time with the Master even if the Follower's
conditions for brake opening have not been met.
10.621 Parameters of Motor Thermal Protection (IDs 704–708)
The motor thermal protection prevents the motor from becoming too hot.
The AC drive can supply a current that is higher than the nominal current. The high current can be necessary to the load, and it must
be used. In these conditions, there is a risk of a thermal overload. Low frequencies have a higher risk. At low frequencies, the cooling
effect and the capacity of the motor decrease. If the motor has an external fan, the load reduction at low frequencies is small.
The motor thermal protection is based on calculations. The protection function uses the output current of the drive to know what is
the load on the motor. If the control board is not energized, the calculations are reset.
The motor thermal protection can be adjusted with parameters. The thermal current IT specifies the load current above which the
motor is overloaded. This current limit is a function of the output frequency.
The thermal stage of the motor can be monitored on the control panel display. See the User Manual of the product.
When using long motor cables (maximum 100 m) with small drives (≤1.5 kW), the motor current that the drive measures can be
much higher than the actual motor current. It is because there are capacitive currents in the motor cable.
C A U T I O N
MOTOR DAMAGE HAZARD
If the airflow is blocked, the function does not protect the motor, and the motor can become too hot.
Make sure that the airflow to the motor is not blocked.
AB296635287482en-000301 / DPD00903 308 | Danfoss A/S © 2023.02
Parameter Descriptions
VACON® NX All-in-One
Application Guide