CABLE SELECTION CHARTS

 

The information contained in this section is based on a cable's individual thermal and electrical limitaions. These charts and formulas exhibit the proper method for selecting the size of cable necessary to perform most resistance welding.

 

SIZING

Throughout this website the notation MCM is used to designate the size of cable.

M=Roman numeral for thousands (1000)
CM=Circular mil or area of wire
Example: 1,273 MCM = 1,273,000
Circular Mils= 1 square inch.

The following formula is the first step in determing the size of kickless, water-cooled and air-cooled cables.

Continuous RMS
Current (amperes) = Secondary Weld
Current x % Duty Cycle + Flow Factor


  

Information necessary to apply the formula is as follows:

1. Number of cycles of weld current or "on time"
2. Number of welds per minute
3. Secondary weld Current (amperes)

This information is necessary to figure:


When you find the "Continuous RMS Current", select the chart that is applicable to the cable type; read across the horizontal line from the Amperes found to the specific length required. If the point of the intersection does not fall on an angled line of a specific MCM cable size, move up to the next higher MCM size.

 






WATER COOLED CABLES


"Water-Cooled Cables" are figured the same way as "Kickless Cables" due to the "Flow Factor". The only difference is a separate graph is used for the selection.

 Flow Factor Conversion for flow rates other than 2 GPM.

FLOW RATE /GALS. PER MIN.
FLOW FACTOR
1.0
.50
1.5
.75
2.0
1.00
2.5
1.25
3.0
1.50
4.0
2.00

In the "Example" for "Kickless Cables", if the "Flow Rate" was 1.5 GPM, the RMS amperes would be 8297. The cable selection for the 8' long cable would now be a 500 MCM and for the 10' long, a 650 MCM would be required.

As you can see, knowing what your water flow rate is very important. Improper water flow is the largest single cause of premature cable failure. There are two water ports available on each terminal of the kickless cable.

We recommend that you use both of them if at all possible. The water should always be fed from the lowest point. On most portable gun stations, the water inlet should be from the gun end. We recommend that the water be fed directly and not in series with the gun.





 

Electro-Max Manufacturing Company

567 Miller Road
Avon Lake, OH 44012