Caution – Yaskawa GPD503 User Manual
Page 10

Refer to Sheet 1 for latest change.
DWG. NO. 02Y00025-0393
SHEET NO. 1 0 OF 10
R E L . 4 / 2 6 / 9 6
Table 4
SYMPTOM
POSSIBLE CAUSE
CORRECTIVE ACTION
Thermal relay 1OL trips
Short circuited main circuit
– Replace unit.
with no deceleration.
discharging transistor 1TR in
braking unit.
– Remove short circuit across
terminals B1 and E1 of 1TR.
Overvoltage (OV) fault
Braking resistor unit capacity too
Check the braking condition.
trip indicated by drive.
small for load (“BRAKE” lamp lit
instantaneously).
Wrong wiring.
Correct.
Unsuitable combination of drive
Select proper DB units.
and DB units.
Braking unit failure.
Replace unit.
Thermal relay sometimes
Braking resistor unit capacity too
Check the braking condition.
trips.
small.
Wrong thermal relay setting.
Check protective coordination of
the braking resistor unit and the
thermal relay.
After thermal relay trips,
Wrong resetting mode selected in
Set reset selection slide switch
the relay does not reset.
braking unit.
in braking unit for automatic
reset.
Faulty thermal relay.
Replace braking unit.
13. The trim potentiometer indicated by reference
designator P1 is used to adjust the brake module turn
on voltage. This level is set at t he factory and under
normal operation, does not need to be adjusted.
Operational Check
NOTE: During the dynamic braking operation, the
operation indicating (“BRAKE”) lamp in the braking
unit lights.
14. During dynamic braking operations, make sure
that the required deceleration characteristic is
obtained. If not, contact
Yaskawa
for assistance.
CAUTION
DURING NORMAL OPERATION, THE BRAKING
UNIT AND THE BRAKING RESISTOR UNIT MUST
BE KEPT CLOSED, SINCE HIGH VOLTAGE IS
APPLIED TO THE DYNAMIC BRAKING CIRCUIT.
15. Reinstall and secure front covers on drive and
braking unit(s), and close and secure the terminal
box(es) on the braking resistor unit(s).
16. Place this instruction sheet with the drive Technical
Manual.
This completes the installation of this option.
TROUBLESHOOTING
To troubleshoot the dynamic braking circuit (braking unit
and braking resistor unit), refer to Table 4.