Closed Loop Drive System; Programming Of Torque Limit And Stop - Danfoss FC 300 Design Manual

FC 300 Design Guide

Closed Loop Drive System

A drive system consist usually of more elements
as:
• Motor
• Add
(Gearbox)
(Mechanical Brake)
• FC 302 AutomationDrive
• Encoder as feed-back system
• Brake resistor for dynamic braking
• Transmission
• Load
Applications demanding mechanical brake control
will usually need a brake resistor.

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.
The example given below illustrates the programming of frequency converter connections.
The external brake can be connected to relay 1 or 2, see paragraph Control of Mechanical Brake. Program
terminal 27 to Coast, inverse [2] or Coast and Reset, inverse [3], and program terminal 29 to Terminal
mode 29 Output [1] and Torque limit & stop [27].
Description:
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, terminal 29 Output
(programmed to Torque limit and stop [27]) is activated. The signal to terminal 27 l changes from 'logic
1' to 'logic 0', and the motor starts to coast, thereby ensuring that the hoist stops even if the frequency
converter itself cannot handle the required torque (i.e. due to excessive overload).
- Start/stop via terminal 18
Par. 5-10 Start [8]
- Quickstop via terminal 27
Par. 5-12 Coasting Stop, Inverse [2]
- Terminal 29 Output
Par. 5-02 Terminal 29 Mode Output [1]
Par. 5-31 Torque Limit & Stop [27]
- Relay output [0] (Relay 1)
Par. 5-40 Mechanical Brake Control [32]
Application Examples
Basic Set-up for FC 302 Closed Loop Speed Control
MG.33.B7.02 - VLT is a registered Danfoss trademark
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