17.13 Closed-loop Drive System
A closed-loop drive system usually consists of the
following:
•
Motor
•
Frequency converter
•
Encoder as feedback system
•
Mechanical brake
•
Brake resistor for dynamic braking
•
Transmission
•
Gear box
•
Load
Applications demanding mechanical brake control typically
needs a brake resistor.
Motor
Gearbox
Load
Transmission
Encoder
Mech. brake
Brake resistor
130BA120.10
Illustration 17.7 Basic Set-up for FC 302 Closed-loop Speed
Control
17.14 Programming of Torque Limit and
Stop
In applications with an external electro-mechanical brake,
such as hoisting applications, it is possible to stop the
frequency converter via a standard stop command and
simultaneously activate the external electro-mechanical
brake.
shows the programming of these frequency
converter connections.
If a stop command is active via terminal 18 and the
frequency converter is not at the torque limit, the motor
ramps down to 0 Hz.
If the frequency converter is at the torque limit and a stop
command is activated, the system activates terminal 29
Output (programmed to
[27] Torque limit & stop
). The signal
to terminal 27 changes from logic 1 to logic 0 and the
motor starts to coast, ensuring that the hoist stops even if
the frequency converter itself cannot handle the required
torque, for example due to excessive overload.
To program the stop and torque limit, connect to the
following terminals:
•
Start/stop via terminal 18
parameter 5-10 Terminal 18 Digital Input
[8] Start
•
Quick stop via terminal 27
parameter 5-12 Terminal 27 Digital Input
[2]
Coasting Stop, Inverse
•
Terminal 29 Output
parameter 5-02 Terminal 29 Mode
[1] Terminal 29
Mode Output
parameter 5-31 Terminal 29 Digital Output
[27]
Torque limit & stop
•
Relay output [0] (Relay 1)
parameter 5-40 Function Relay [32] Mechanical
Brake Control
12
13 18
37
32
27
19
29
33 20
+24 V
P 5-10 [8]
P 5-12 [2]
P 5-02 [1]
P 5-31 [27]
GND
P 5-40 [0] [32]
Rela
y 1
01 02 03
-
+
130BA194.11
External
24 V DC
Mechanical brake
connection
Start
I
max
0.1 Amp
Illustration 17.8 Stop and Torque Limit Terminal Connections
Application Examples
VLT
®
Parallel Drive Modules
158
Danfoss A/S © 6/2016 All rights reserved.
MG37N102
17
17
Summary of Contents for VLT 380-500 V
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