Braking Resistor With Over-Heat Protection And Gtr7 Monitoring (Air-Cooled); Figure 30: Braking Resistor With Over-Heat Protection Without Gtr7 Monitoring - KEB COMBIVERT F5 Instruction Manual

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

This circuit offers a direct protection with defective GTR7 (braking transistor). The braking re-
sistor overheats and opens the OH terminals with defective GTR7. The OH terminals open the
holding circuit of that 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 operation
is also secured by the internal fault disconnection. The input must be programmed and invert-
ed to "external error". Automatic restarting after cooling of the braking resistor is prevented by
the self-holding circuit of K3.
Info
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
(see "Use of the temperature input in PTC mode").
The picture below is only an example and has to be adapted according to the application.
L1
L2
L3
F
1
K3
2
DR1
HF1
L1 L2 L3
PE
PB
OH1
OH2
Figure 30:
K3 Line contactor with auxiliary con-
tacts
S1 Key for switch on
S2 Emergency stop circuit braker for
switch off
H1 Tripping control
G1 Inverter with programmable input I1
Terminals T1/T2 and example picture
3 5 11
4 6
12
OH
OH
G1
T1 T2 U
+PA
R1
R2
Braking resistor with over-heat protection without GTR7 monitoring
+24V
13
14
0V I1
V W
R1 Braking resistor with temperature switch
R2 PTC/KTY84 sensor e.g. of the motor
DR1 Mains choke with temperature switch
(optional)
HF1 HF filter
S2
OH1
R1
OH2
OH1
DR1
OH2
S1
K3
GND
14
K3
13
I1
G1
0V
12
K3
11
H1
37