Installation - Danfoss VLT HVAC Drive FC 102 Installation Manual

Safe Torque Off
Installation Guide

1 Installation

1.1 Safety and Installation Awareness
Before starting installation, familiarize yourself with all safety guidelines and precautions in this installation guide. Additional resour-
ces – including the Safe Torque Off Operating Guide (130R0544), which contains technical data and application examples – can be
downloaded at www.danfoss.com.
1.2 Qualified Personnel
Only qualified personnel are allowed to install, commission, and maintain Danfoss drives. Qualified personnel are trained individuals
who are familiar with and authorized to mount and wire the drive in accordance with pertinent laws and regulations. Also, qualified
personnel must be familiar with the instructions and safety measures described in this installation guide.
1.3 Safety Precautions
LACK OF SAFETY AWARENESS
This guide gives important information on preventing injury and damage to the equipment or the system. Ignoring this informa-
tion can lead to death, serious injury, or severe damage to the equipment.
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Make sure to fully understand the dangers and safety measures present in the application.
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Before performing any electrical work on the drive, lock out and tag out all power sources to the drive.
NO ELECTRICAL SAFETY
When Safe Torque Off (STO) is activated by removing the 24 V DC voltage supply to terminal 37, it does not provide electrical
safety. The STO function itself is not sufficient to implement the Emergency-Off function as defined by EN 60204-1. Using the STO
function to implement Emergency-Off may lead to personal injury.
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Emergency-Off requires measures of electrical isolation, for example, by switching off mains via an extra contactor.
RISK OF ELECTRICAL SHOCK
The Safe Torque Off (STO) function does not isolate mains voltage to the drive or auxiliary circuits. Only perform work on electri-
cal parts of the drive or the motor after isolating the mains voltage supply and waiting for the discharge time to elapse, as speci-
fied on the drive nameplate. Failure to isolate the mains voltage supply from the unit and waiting the time specified could result
in death or serious injury.
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Do not stop the drive by using the STO function. If a running drive is stopped by using the function, the unit trips and stops
by coasting. If this limitation is not acceptable, for example because it causes danger, use the appropriate stopping mode to
stop the drive and machinery before using the STO function. Depending on the application, a mechanical brake may be re-
quired.
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STO is suitable for performing mechanical work on the drive system or affected area of a machine only. It does not provide
electrical safety. STO must not be used as a control for starting and/or stopping the drive.
RESIDUAL ROTATION
The STO function can be used for asynchronous, synchronous, and permanent magnet motors. Two faults can occur in the power
semiconductor of the drive. When using synchronous or permanent magnet motors, a residual rotation can result from the faults.
The rotation can be calculated to angle = 360/(number of poles). The application using synchronous or permanent magnet mo-
tors must consider this residual rotation and ensure that it does not pose a safety risk. The situation is not relevant for asynchro-
nous motors.
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Installation
AN41701943885102-000101 / 130R1274 | 3