Estimate coolant flow requirements, hose size, velocity, and pressure-drop risk for resistance welding systems including weld guns, transformers, secondary cables, holders, arms, and cooling circuits.
Use this as a practical screening tool for concept sizing, troubleshooting hot weld components, and checking whether a cooling circuit may be undersized before production issues show up.
This calculator estimates total coolant flow, line velocity, and pressure-drop risk for a resistance welding cooling circuit. It is meant as a practical starting point for weld guns, transformers, secondary cables, shunts, holders, arms, and similar water-cooled components.
This works best for concept sizing, troubleshooting, retrofit checks, and early machine review. Actual delivered flow still depends on manifold design, quick disconnects, internal passages, coolant temperature, branch balance, and OEM requirements.
The goal is not to replace an OEM thermal model. The goal is to help you quickly answer whether the requested flow, line size, pressure drop, and velocity look reasonable before you chase weld schedule issues that may actually be cooling related.
Totals your target device flow, applies a simultaneous use factor, and adds a safety factor to estimate the recommended total circuit flow.
Estimates velocity through the selected main supply line so you can see whether the hose may be too small or larger than needed.
Uses a simplified pressure-drop model to flag circuits that may be too long, too restrictive, or undersized for the requested flow.
Recommends a minimum nominal line size based on the requested flow and preferred maximum velocity.
Cooling problems in resistance welding often show up as weld instability, short tip life, hot cables, overheated transformers, drifting weld quality, or nuisance water faults. Use this workflow before assuming the weld schedule is the only problem.
Enter the cooled component type, number of branches, target flow per device, simultaneity factor, safety factor, coolant type, line size, equivalent length, available pressure, allowable pressure drop, fitting restriction level, and preferred maximum velocity.
The calculator returns base flow, recommended total flow, line velocity, estimated pressure drop, pressure margin, suggested minimum line size, and warning notes for common cooling risks.
Save coolant sizing scenarios, reload prior inputs, and compare alternatives quickly.
This calculator totals your target device flow, applies a simultaneity factor, adds a safety factor, and then checks whether the selected line size looks reasonable.
It estimates line velocity directly from flow and line ID, then uses a simplified pressure-drop model to flag circuits that look undersized, too restrictive, or sensitive to real-world fittings and internal passages.
It is intentionally built as a practical screening tool, not as an OEM-certified thermal model.
Base flow is the number of devices multiplied by target flow per device and adjusted by the simultaneous use factor.
Recommended flow is the base flow multiplied by the safety factor to leave practical margin for real circuit restrictions.
Velocity is calculated from recommended flow and selected hose ID. High velocity usually means the selected line may be too small.
Pressure drop is estimated from flow, line ID, equivalent length, restriction multiplier, and coolant type.
If velocity is above your preferred maximum, the main line may be too small or the circuit may be too restrictive. This can create unnecessary pressure loss and reduce delivered flow.
Low velocity is not automatically bad, but it can indicate the selected line is larger than necessary for the requested flow.
If estimated pressure drop is above the allowable limit, the line may be undersized, the run may be too long, or fittings and disconnects may be adding too much restriction.
Low margin means delivered flow may suffer once real fittings, quick disconnects, manifolds, valves, and internal passages are included.
If the suggested line size is larger than the selected hose ID, the selected line is likely too small for the requested flow and velocity target.
Multiple branches increase the risk of uneven flow. Parallel circuits often need balancing to prevent one device from being starved.
Cooling ties directly into weld consistency, electrode life, cable temperature, transformer health, and thermal stability. A weld process can look like it has a bad schedule when the real problem is poor cooling.
Low flow can increase heat at electrodes, holders, and arms. That can shorten tip life, increase mushrooming, and cause schedule drift.
Weld transformers, secondary cables, shunts, and holders can overheat if coolant flow is too low or passages are restricted.
Undersized lines can create high velocity, unnecessary pressure loss, reduced delivered flow, and greater sensitivity to fittings.
Long runs, quick disconnects, elbows, valves, manifolds, and small internal passages can reduce delivered flow even when supply pressure looks acceptable.
Parallel branches may still give uneven cooling if one path is more restrictive than the others. Flow will favor the easier path.
Water/glycol mixtures usually add some flow resistance compared to plain water, so results should be treated as screening estimates.
Hot secondary cables or shunts often point to low flow, blocked passages, undersized lines, or excessive restriction.
If the transformer runs hot, check flow rate, water temperature, restrictions, and whether the circuit is shared with too many devices.
Cooling issues can make tips wear fast even when the weld schedule appears reasonable.
Heat buildup can change weld behavior over time, especially during production runs with high duty cycle.
Weak return flow may indicate restriction, branch imbalance, kinked lines, plugged fittings, or poor manifold layout.
Use this when replacing hoses, adding branches, changing guns, or moving equipment farther from the supply manifold.
Use this page to screen the circuit, then verify actual delivered flow at the machine whenever possible. A system can look acceptable on paper and still underperform because of branch imbalance, plugged passages, quick disconnect restriction, or internal component limits.
Cooling ties directly into weld consistency, tip life, thermal stability, and machine reliability. Use these related tools to review the rest of the weld process.
If you are trying to size a new cooling loop, fix hot weld cables, troubleshoot inconsistent temperature, or check whether a weld circuit is being starved, you can reach out for help on a real machine.
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