Motive DELPHI ATDC Ex 2GD, Manual Addendum

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Manual Addendum DELPHI ATDC Ex 2GD
pag 8/20
REV.03
Electrical and thermal protections
Protections must be chosen based on the specific running conditions, according to standards EN60079-14 and
EN61241-14.
External protections:
•
Protection against overcurrent and short-circuits; this protection can be made with the magnetothermic circuit
breaker or with fuses; these must be calibrated on the motor current.
•
Protection against overload by thermal relay that controls a power line contactor upstream the motor.
•
If the application requires, protection against excessive speed of the electric motor, for example if the mechanical
load may drive the electric motor itself and thereby create a hazardous situation.
•
If special conditions or synchronised operation with other machines or parts of machines require it, protection
against power failures or dips by means of a minimum voltage relay that controls an automatic power knife switch.
Internal protections:
The electrical protections on the motor power supply may not be sufficient to protect against overloads.
Connecting built-in protections on the windings solves this problem:
•
PTO bimetallic probe (normally-closed electromechanical device that becomes open when the threshold
temperature is reached).
The reset of this cut-out must be performed manually only, and not automatically. The user, in compliance with the
norms, must use a tripping relay out in compliance with IEC 61508 standard (Fail Safe type).
Motive Delphi-Ex motors, up to size 132 included, are equipped as standard with 3 PTO 130°C bimetallic probes.
•
PTC thermistor (device that suddenly changes positively its resistance when the threshold temperature is reached).
Motive Delphi-Ex motors, from size 160 included, are equipped as standard with 3 PTC 130°C thermistors.