Implementing a motor temperature sensor connection
WARNING!
IEC 61800-5-1 requires double or reinforced insulation between live parts and
accessible parts when:
• the accessible parts are not conductive, or
• the accessible parts are conductive, but not connected to the protective earth.
Obey this requirement when you plan the connection of the motor temperature
sensor to the drive.
You have these implementation alternatives:
1. If there is double or reinforced insulation between the sensor and the live parts of
the motor: You can connect the sensor directly to the analog/digital input(s) of the
drive. See the control cable connection instructions. Make sure that the voltage
does not exceed the maximum allowed voltage over the sensor.
2. If there is basic insulation between the sensor and the live parts of the motor: You
can connect the sensor to the analog/digital input(s) of the drive. All other circuits
connected to the digital and analog inputs (typically extra-low voltage circuits) must
be:
• protected against contact, and
• insulated with basic insulation from other low-voltage circuits. The insulation
must be rated for the same voltage level as the drive main circuit.
Note: Extra-low voltage circuits (for example, 24 V DC) typically do not meet these
requirements.
Make sure that the voltage does not exceed the maximum allowed voltage over the
sensor.
As an alternative, you can connect the sensor with basic insulation to the
analog/digital input(s) of the drive, if you do not connect any other external control
circuits to the drive digital and analog inputs.
3. You can connect the sensor to the drive via an option module. The sensor and the
module must form a double or reinforced insulation between the motor live parts
and the drive control unit. See Connecting motor temperature sensor to the drive
via an option module (page 76). Make sure that the voltage does not exceed the
maximum allowed voltage over the sensor.
4. You can connect a sensor to a digital input of the drive via an external relay. The
sensor and the relay must form a double or reinforced insulation between the motor
live parts and the digital input of the drive. Make sure that the voltage does not
exceed the maximum allowed voltage over the sensor.
Guidelines for planning the electrical installation 75
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