Danfoss VLT AutomationDrive FC 301 Series Design Manual page 161

Application Examples
10.1.1 Closed-loop Drive System
An adjustable frequency drive system consist usually of
more elements such as
•
Motor
•
Gearbox
•
Mechanical Brake
•
Adjustable frequency drive
•
Encoder as feedback system
•
Brake resistor for dynamic braking
•
Transmission
•
Load
Applications demanding mechanical brake control usually
need a brake resistor.
Motor
Encoder Mech. brake
Figure 10.5 Example of FC 302 Closed-loop Speed Control
MG33BF22
Design Guide
Brake resistor
Transmission
Gearbox
Load
Rev. 2014-04-04 All rights reserved.
10.1.2 Programming of Torque Limit and
Stop
In applications with an external electro-mechanical brake,
such as hoisting applications, it is possible to stop the
adjustable frequency drive via a 'standard' stop command
and simultaneously activate the external electro-
mechanical brake.
The example given below illustrates the programming of
adjustable frequency drive connections.
The external brake can be connected to relay 1 or 2.
Program terminal 27 to [2] Coast, inverse or [3] Coast and
Reset, inverse, and program terminal 29 to [1] Terminal
mode 29 Output and [27] Torque limit & stop.
Description
If a stop command is active via terminal 18 and the
adjustable frequency drive is not at the torque limit, the
motor ramps down to 0 Hz.
If the adjustable frequency drive is at the torque limit and
a stop command is activated, terminal 29 Output
(programmed to [27] Torque limit and stop) is activated.
The signal to terminal 27 changes from 'logic 1' to 'logic 0',
and the motor starts to coast, thereby ensuring that the
hoist stops even if the adjustable frequency drive itself
cannot handle the required torque (i.e., due to excessive
overload).
•
Start/stop via terminal 18
5-10 Terminal 18 Digital Input, [8] Start
•
Quickstop via terminal 27
5-12 Terminal 27 Digital Input, [2] Coasting Stop,
Inverse
•
Terminal 29 Output
5-02 Terminal 29 Mode, [1] Terminal 29 Mode
Output
5-31 Terminal 29 digital Output, [27] Torque Limit &
Stop
•
Relay output [0] (Relay 1)
5-40 Function Relay, [32] Mechanical Brake Control
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