AI and AO (or AI, DI and +10 V) as PTC motor temperature sensor interface
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.
To comply with the drive safety standard IEC 61800-5-1:
If the motor temperature sensor has double or reinforced insulation vs. the motor
windings, you can connect it directly to the drive IO interface. This section shows
two connection alternatives for the direct I/O connection. If the sensor does not
have reinforced insulation, you must use another type of connection to comply
with the safety standard. See Implementing a motor temperature sensor
connection (page 60).
See the firmware manual for information on the related Motor thermal protection
function, and the required parameter settings.
PTC connection 1
1…3 PTC sensors can be connected in series to an analog input and an analog
output. Make sure that the voltage does not exceed the maximum allowed voltage
over the sensor. The analog output feeds a constant excitation current of 1.6 mA
through the sensor. The sensor resistance increases as the motor temperature
rises, as does the voltage over the sensor. The temperature measurement function
calculates the resistance of the sensor and generates an indication if
overtemperature is detected. Leave the sensor end of the cable shield unconnected.
110 Electrical installation – North America
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