Miyachi Unitek ISA Series, Руководство оператора

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ISA-4001CR INVERTER POWER SUPPLY
990-364 D-1
APPENDIX D
WIRE GAUGE SELECTION AND
CIRCUIT BREAKER SETTING
Sizing Power Input Lines and Transformer Input Lines
Due to the many possible combinations of transformer ratios, total secondary resistance and weld
voltages, all which have a direct relationship for cable sizing, this section assumes that the secondary
current of the ISA series is at its maximum peak current during the weld.
Wire gauges for the AC Mains and Output lines to the transformer must meet the following criteria:
a. For the 480 VAC 3 phase lines, the voltage drop must be less than 5%. Note also, that if the 480
voltage source drops by 1% then the cable allowance is reduced to 4% maximum. Ampacity
must be in accordance with local codes.
b. For the Output lines to the transformer it is recommended that voltage loss does not exceed 1%.
The unit is designed to have dual output cables on each primary output (4 cables total).
Ampacity must be in accordance with local codes.
In general:
The input current is the same for a 480 VAC ISA-4001CR or a 575 VAC ISA-4001CR.
Size all cables for the maximum secondary current anticipated for your installation. Preferred
would be at full capability of 1400 amps at 100% duty cycle for the ISA-4001CR.
Minimize cable length as much as possible.
If in doubt use a larger gauge cable.
Use the minimum number of connections as possible.
Insure that all connections are tight.
Formulas used:
I
Eff
= Output current times the square root of the duty cycle.
I
ph
= Resultant (I
Eff
x 0.817 ) current in each phase of the 3-phase input source.