Implementing an ATEX-certified motor thermal protection
With option +Q971, the drive provides ATEX-certified safe motor disconnection without
contactor using the drive Safe torque off function. To implement the thermal protection of
a motor in explosive atmosphere (Ex motor), you must also:
• use an ATEX-certified Ex motor
• order an ATEX-certified thermistor protection module for the drive (option +L537), or
acquire and install an ATEX-compliant protection relay
• do the necessary connections.
For more information, see:
Manual code
(English)
User's manual
3AXD50000030058
CPTC-02 ATEX-certified thermistor protection module, Ex II (2) GD (option +L537+Q971)
user's manual
Controlling a contactor between drive and motor
The control of the output contactor depends on how you use the drive, that is, which motor
control mode and which motor stop mode you select.
If you have the vector control mode and motor ramp stop selected, open the contactor as
follows:
1. Give a stop command to the drive.
2. Wait until the drive decelerates the motor to zero speed.
3. Open the contactor.
If you have the vector control mode and motor coast stop, or scalar control mode selected,
open the contactor as follows:
1. Give a stop command to the drive.
2. Open the contactor.
WARNING!
When the vector control mode is in use, never open the output contactor while the
drive controls the motor. The vector control operates extremely fast, much faster
than it takes for the contactor to open its contacts. When the contactor starts
opening while the drive controls the motor, the vector control will try to maintain
the load current by immediately increasing the drive output voltage to the maximum.
This will damage, or even burn the contactor completely.
Implementing a bypass connection
If bypassing is required, employ mechanically or electrically interlocked contactors between
the motor and the drive and between the motor and the power line. Make sure with
interlocking that the contactors cannot be closed simultaneously. The installation must be
clearly marked as defined in IEC/EN 61800-5-1, subclause 6.5.3, for example, “THIS
MACHINE STARTS AUTOMATICALLY”.
Guidelines for planning the electrical installation 91
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