Installation requirements:
The overall electrical safety of the adjustable frequency drive requires special installation considerations regarding:
• Fuses and circuit breakers for overcurrent and short-circuit protection
• Selection of power cables (line power, motor, brake, load sharing and relay)
• Grid configuration (grounded delta transformer leg, IT,TN, etc.)
• Safety of low-voltage ports (PELV conditions).
Consult the relevant clauses in these instructions and in the VLT HVAC Drive
Design Guide
for information about the installation requirements.
2.1.6 Installation at High Altitudes (PELV)
Installation at high altitude:
380–480 V: At altitudes above 9842 ft [3 km], please contact Danfoss regarding PELV.
525–690 V: At altitudes above 6,600 feet [2 km], please contact Danfoss regarding PELV.
2.1.7 Avoid unintended start
While the adjustable frequency drive is connected to line power, the motor can be started/stopped using digital commands, bus com-
mands, references or via the Local Control Panel.
• Disconnect the adjustable frequency drive from line power whenever personal safety considerations make it necessary to
avoid an unintended 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 line power supply, or lost motor
connection may cause a stopped motor to start.
2.1.8 Safe Stop of the Adjustable Frequency Drive
For versions equipped with a Safe Stop terminal 37 input, the adjustable frequency drive can perform the safety function
Safe Torque Off
(as defined by
draft CD IEC 61800-5-2) or
Stop Category 0
(as defined in EN 60204-1).
It is designed and approved suitable for the requirements of Safety Category 3 in EN 954-1. This functionality is called Safe Stop. Prior to integration and
use of Safe Stop in an installation, a thorough risk analysis on the installation must be carried out in order to determine whether the Safe Stop functionality
and safety category are appropriate and sufficient. In order to install and use the safe stop function in accordance with the requirements of Safety Category
3 in EN 954-1, the related information and instructions of the VLT HVAC Drive
Design Guide
must be followed! The information and instructions of the
Instruction Manual are not sufficient for a correct and safe use of the safe stop functionality!
VLT HVAC Drive High Power Instruction Man-
ual
2 Safety
MG.11.F3.22 - VLT
®
is a registered Danfoss trademark
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