2.1.5 Avoid unintended start
While the frequency converter is connected to mains, the motor can be started/stopped using digital commands, bus commands,
references or via the Local Control Panel.
• Disconnect the frequency converter from mains whenever personal safety considerations make it necessary to avoid unin-
tended start.
• To avoid unintended start, always activate the [OFF] key before changing parameters.
• Unless terminal 37 is turned off, an electronic fault, temporary overload, a fault in the mains supply, or lost motor connection
may cause a stopped motor to start.
2.1.6 Safe Stop Installation
To carry out an installation of a Category 0 Stop (EN60204) in
conformity with Safety Category 3 (EN954-1), follow these in-
structions:
1. The bridge (jumper) between Terminal 37 and 24 V DC must be
removed. Cutting or breaking the jumper is not sufficient. Re-
move it entirely to avoid short-circuiting. See jumper on illus-
tration.
2. Connect terminal 37 to 24 V DC by a short-circuit protected ca-
ble. The 24 V DC voltage supply must be interruptible by an
EN954-1 Category 3 circuit interrupt device. If the interrupt de-
vice and the frequency converter are placed in the same instal-
lation panel, you can use an unscreened cable instead of a
screened one.
Illustration 2.1: Bridge jumper between terminal 37 and 24
VDC
The illustration below shows a Stopping Category 0 (EN 60204-1) with safety Category 3 (EN 954-1). The circuit interrupt is caused by an opening door
contact. The illustration also shows how to connect a non-safety related hardware coast.
Illustration 2.2: Illustration of the essential aspects of an installation to achieve a Stopping Category 0 (EN 60204-1) with safety Category
3 (EN 954-1).
VLT HVAC Low Harmonic Drive Operating In-
structions
2 Safety
MG.16.A1.02 - VLT
®
is a registered Danfoss trademark 9
2
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