Braking Resistor With Over-Heat Protection And Gtr7 Monitoring (Air-Cooled Inverters) - KEB COMBIVERT F5 Series Instruction Manual

Connection Power Unit

2.7.5.3 Braking resistor with over-heat protection and GTR7 monitoring (air-cooled inverters)

This circuit offers a direct protection with defective GTR7 (braking transistor). The braking
resistor overheats and opens the OH terminals with defective GTR7. The OH terminals open
the holding circuit of the input contactor, so that the input voltage is switched off in error case.
An error in inverter is released by opening the auxiliary contacts of K3. Regenerative opera-
tion is also secured by the internal fault disconnection. The input must be programmed and
inverted to "external error". Automatic restarting after cooling of the braking resistor is pre-
vented by the self-holding circuit of K3.
Braking resistor with over-heat protection without GTR7 monitoring
L1
L2
L3
F
1
K3
2
DR1
HF1
L1 L2 L3
PE
PB
OH1
OH2
K3 Line contactor with auxiliary contacts
S1 Key for switch on
S2 Emergency stop circuit braker for switch off DR1 Mains choke with temperature switch (optional)
H1 Tripping control
G1 Inverter with programmable input I1
If the PTC/KTY evaluation of the motor at terminals T1/T2 is not used, these
terminals can be used instead of the programmable input. The temperature
input must be operated in PTC mode.
3 5 11
4 6
12
OH1
OH2
G1
T1 T2
+PA U
R1
R2
+24V
13
14
0V I1
V W
R1 Braking resistor with temperature switch
R2 PTC/KTY84 sensor e.g. of the motor
HF1 HF filter
S2
OH2
R1
OH1
OH2
DR1
OH1
S1
K3
GND
14
K3
13
I1
G1
0V
12
K3
11
H1
GB - 31