Operation Principle; Without An Fso Module - ABB ACS880 Series User Manual

ATEX-certified motor thermal protection function with Pt100 relays (+L514+Q971) 31
The temperature measurement circuit of ABB motors has basic insulation. For information
on the insulation of the Pt100 relay, see the applicable relay data sheet.
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Operation principle

Without an FSO module

1. When the motor temperature rises, the sensor resistance increases linearly.
2. When the motor temperature exceeds the set operating temperature limit of the Pt100
relay, the relay indicates motor overtemperature through its output contacts.
3. The opening contacts of the extension relay(s) [-A81] ([-A82] and [-A83]) open the STO
circuit of the drive. This prevents the drive from generating the torque required to rotate
the motor.
4. The drive generates an STO indication (parameter 31.22).
5. If the extension relay(s) [-A81] ([-A82] and [-A83]) are wired to a digital input, the loss
of the signal triggers a motor overtemperature fault in the drive.
6. After the motor temperature has decreased to normal, the Pt100 relays reset
automatically.
7. The user must reset the drive faults either from the reset source defined by the user
(parameter 31.11) or locally with the drive control panel:
• the STO fault in the drive (if configured with drive parameter 31.22)
• the motor overtemperature fault in the drive (if configured).