R
C
221
222
421
428
324
325
321
313
314
315
IVT
44,7V
ICT
1:10
0V
120V 50/60Hz
230V 50/60Hz
RXTTE4
IEC13000028-1-en.vsd
IEC13000028 V1 EN-US
Figure 29.
Voltage injection unit RXTTE4 with its main internal
components
Rotor earth fault protection can be
integrated in the IED among all other
protection functions typically required for
generator protection. How this is achieved
by using COMBIFLEX injection unit
RXTTE4 is described in Instruction
1MRG001910.
SEMOD175176-2 v5
Table 2. Rotor earth fault protection based on General current and voltage protection (CVGAPC) and RXTTE4
Function
Range or value
For machines with:
• rated field voltage up to
350 V DC
• static exciter with rated supply
voltage up to
700 V 50/60 Hz
Supply voltage 120 or 230 V
50/60 Hz
Operate earth fault resistance
value
Approx. 1–20 kΩ
Influence of harmonics in the DC
field voltage
Negligible influence of 50 V, 150
Hz or 50 V, 300 Hz
Permitted leakage capacitance
(1–5) μF
Permitted shaft earthing
resistance
Maximum 200 Ω
Protective resistor
220 Ω, 100 W, plate
(the height is 160 mm (6,2
inches) and width 135 mm (5,31
inches))
External resistor for RXTTE4
GUID-53080A2D-E836-4827-AD3D-8BD2C1E388D0 v2
The external resistor is used when either there is a need to
minimize physical exposure of the field circuit or when high
harmonic content of the total injection current can cause
overheating of the built-in RXTTE4 resistor. The external
resistor is delivered mounted on an insulated plate with
overall dimensions; (the height is 160 mm (6,2 inches) and
width 135 mm (5,31 inches)), suitable for wall mounting, see
. It actually consists of two resistors (R1 and R2)
which are on delivery connected in series. It is possible to
order two different types of the external resistor. The first
670/650 series and SAM600-IO IEC
1MRK 514 012-BEN K
20
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