Safe Torque Off Operation (Fc 302 Only); Liability Conditions; Additional Information; Installation Of External Safety Device In Combination With Mcb - Danfoss VLT AutomationDrive FC 300 Design Manual

Product Introduction
3.12.2 Safe Torque Off Operation (FC
302 only)
The Safe Torque Off function of FC 302 can be used for
asynchronous, synchronous, and permanent magnet
3 3 motors. It may happen that 2 faults occur in the frequency
converter's power semiconductor. When using synchronous
or permanent magnet motors, this may cause a residual
rotation. The rotation can be calculated to Angle=360/
(Number of Poles). The application using synchronous or
permanent magnet motors must take this into consid-
eration and ensure that this is not a critical safety issue.
This situation is not relevant for asynchronous motors.

3.12.3 Liability Conditions

Liability conditions
The user is responsible for ensuring that personnel know
how to install and operate the Safe Torque Off function by:
•
Reading and understanding the safety regulations
concerning health and safety/accident prevention
•
Understanding the generic and safety guidelines
given in this description and the extended
description in the Operating Instructions VLT®
Frequency Converters – Safe Torque Off.
•
Having a good knowledge of the generic and
safety standards for the specific application
The user is defined as integrator, operator, service, and
maintenance staff.

3.12.4 Additional Information

For more information regarding Safe Torque Off, including
installation and commissioning, refer to the Operating
Instructions VLT® Frequency Converters – Safe Torque Off.
3.12.5 Installation of External Safety Device
in Combination with MCB 112
If the ex-certified thermistor module MCB 112, which uses
Terminal 37 as its safety-related switch-off channel, is
connected, then the output X44/12 of MCB 112 must be
AND-ed with a safety-related sensor (emergency stop
button or safety-guard switch) that activates Safe Torque
Off. This means that the output to Safe Torque Off
terminal 37 is HIGH (24 V) only if both the signal from MCB
112 output X44/12 and the signal from the safety-related
sensor are HIGH. If at least 1 of the 2 signals is LOW, then
the output to Terminal 37 must be LOW, too. The safety
device with this AND logic itself must conform to IEC
61508, SIL 2. The output connection of the safety device
with safe AND logic to Safe Torque Off terminal 37 must
be short-circuit protected. Illustration 3.40 shows a Restart
54
®
VLT AutomationDrive FC 300 Design Guide 90-1200 kW
input for the external Safety Device. This means that in this
installation, set [7] or [8] 5-19 Terminal 37 Safe Stop. Refer
to the MCB 112 Operating Instructions for further details.
Hazardous
Area
PTC
Sensor
Terminal 37 Safe Stop
Illustration 3.40 Illustration of the Essential Aspects for
Installing a Combination of a Safe Torque Off Application and
an MCB 112 Application
Parameter settings for external safety device in
combination with MCB 112
If MCB 112 is connected, then additional selections ([4]–[9])
become possible for 5-19 Terminal 37 Safe Stop (Terminal
37 Safe Torque Off).
Selections [1]* and [3] 5-19 Terminal 37 Safe Stop are still
available but are not to be used as those are for instal-
lations without MCB 112 or any external safety devices. If
[1]* or [3] 5-19 Terminal 37 Safe Stop should be selected by
mistake and MCB 112 is triggered, then the frequency
converter will react with an alarm "Dangerous Failure
[A72]" and coast the frequency converter safely without
automatic restart.
Selections [4] and [5] 5-19 Terminal 37 Safe Stop are only
selected when MCB 112 uses the Safe Torque Off. If
selections [4] or [5] 5-19 Terminal 37 Safe Stop are selected
by mistake and the external safety device triggers Safe
Torque Off, the frequency converter reacts with an
alarm "Dangerous Failure [A72]" and coasts the frequency
converter safely without automatic restart.
MG34S202 - Rev. 2013-08-19
Non - Hazardous Area
PTC Thermistor Card
MCB112
X44/ 1 2 3 4 5 6 7 8 9
Digital Input
e.g. Par 5-15
12 13 18 19 27 29 32
Par. 5- 19
Safety Device
SIL 2
Safe AND Input
Safe Output
Manual Restart
10 11 12
33 20 37
DI DI
Safe Stop