Thermal Overload Protection For Rotors Rpttr (Ansi 49R) - ABB RELION REX640 Technical Manual

Protection and control

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Table of Contents

1MRS759142 F

Technical data

Table 484: MPTTR Technical data

Characteristic

Operation accuracy

Operate time accuracy

Thermal overload protection for rotors RPTTR (ANSI 49R)

Identification

Function description

Thermal overload protection for ro-

Function block

Figure 244: Function block

Functionality

The thermal overload protection for rotors RPTTR protects the rotor of the

induction motor from overheating. RPTTR models the rotor thermal behavior on the

basis of the measured load current and voltage and disconnects the motor when

the thermal content reaches 100 percent. The rotor thermal overload conditions are

Overload current > 1.2 × Operate level temperature

Technical Manual

Values (Range)

Depending on the frequency of the measured

Current measurement: ±1.5% of the set value

or ±0.002 × I

0.01...4.00 × I

±2.0% of the theoretical value or ±0.50 s

identification

Protection functions

Thermal level of protec-

ted object (1.00 is the

operate level)

(at currents in the range of

identification

ANSI/IEEE C37.2

device number