Miyachi Unitek ISA Series, Operator'S Manual

Page: 92 / 122

APPENDIX D: WIRE GAUGE AND CIRCUIT BREAKER SELECTION
ISA-4001CR INVERTER POWER SUPPLY
D-2 990-364
Circuit Breaker Settings
The dipswitches referred to in his section are located on the ABB circuit breaker,
not
on the ISA
motherboard. The dipswitches are clearly labeled on the circuit breaker. There is a separate ABB
Circuit Breaker Owner’s Manual in a pocket in the front door of the Power Supply, please refer to this
manual if you need more information on the circuit breaker.
The circuit breaker has three adjustments:
ADJUSTMENT TRIP FUNCTION RANGE INDIVIDUAL SETTINGS
L
Long time pick-up 0.4 - 1.0 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.95, 1.0 X I
n.
t1
Long time delay 3.0 - 18 sec A = 3, B = 6, C = 12, D = 18 seconds
I
Instantaneous trip 1.5 - 12.0 1.5, 2.0, 4.0, 6.0, 8.0, 10.0, 12.0, 15.0 X I
n
I
n
= 1200 Amps for ISA-4001CR
*See circuit breaker front panel for dipswitch settings.
Setting L
Calculate the breaker rated current using the Effective secondary current and duty cycle of the weld
schedule.
DC is the duty cycle of the weld schedule in percent.
ISA-4001CR Example:
Output current is 4000amps @ a duty cycle of 12%.
Breaker should be set at 1132 amps or more.
Set the L dipswitch to 1200 amps (1.0).
Setting t1 Set to 3 seconds (A). This setting should require no further adjustment.
Setting I
Set to 6.0 as the maximum peak current is 6400 amps.
NOTE:
If the circuit breaker nuisance trips, set L higher or set I to 8.