How do you calculate rework cost from failed hipot?

Multiply failed units by the rework cost per unit, then add the fixed teardown cost and the retest overhead adder. For 100 units at $2.50 each plus $75 fixed and $25 overhead, the total is $350.

What is the per-unit cost of hipot rework in this example?

Dividing the $350 total by 100 failed motors gives $3.50 per reworked unit, which spreads the fixed $100 of teardown and overhead across the batch on top of the $2.50 direct repair.

When should I scrap a motor instead of reworking a hipot failure?

Compare the per-unit rework cost against the motor's standard cost and its salvage value. If chasing an insulation breakdown approaches the build cost, or risks field reliability, scrap is usually the lower total-cost decision.

Why include a fixed cost and a separate overhead adder?

The fixed cost covers batch-level setup like fixturing the rework cell, while the overhead adder captures retest labor and stand time. Separating them lets you see how much of the $3.50 per unit is truly avoidable versus structural.

What hipot failure rate makes rework cost a real problem?

Even a few percent matters at volume. At $3.50 per reworked unit, a 5% fail rate on 10,000 motors is 500 units and $1,750 of rework, before counting the schedule disruption and any scrapped units.

How do I reduce hipot rework cost?

Attack the root cause upstream: winding nicks, insufficient varnish cure, contamination, or slot-liner damage. Driving the failure rate down beats optimizing the rework cell, because the cheapest hipot rework is the one you never run.

Motors, Generators & Electrification Equipment calculator

Rework from failed hipot Calculator

Hipot (high-potential) test failures on a motor line are expensive because each fail means tearing into a finished unit to find an insulation breakdown, repairing it, and re-running the full electrical sequence. This calculator totals the cost of that rework loop, combining the variable per-motor repair cost with the fixed setup and the retest overhead. Quality engineers and EOL supervisors use it to size scrap-and-rework budgets, justify upstream insulation-process improvements, and put a real dollar figure on a winding or varnish defect that escapes to test. Knowing the per-unit rework cost also tells you when it is cheaper to scrap a motor than to chase the fault.

What this calculator does

Estimate the rework cost for motors or windings that failed hipot (high-potential) testing so teams can quote the rework, compare cost scenarios, and review margin risk.
Use it when hipot rework is being quoted and you need a number you can defend on a phone call.
It computes the total cost to rework a batch of motors that failed hipot, plus the resulting cost per reworked unit.

Formula used

Total hipot rework cost = units failing hipot × rework cost per unit + fixed rework cost + labor and test overhead adder
Cost per unit = total hipot rework cost ÷ units failing hipot

Inputs explained

Motors failing hipot:
Rework cost per failed motor:
Fixed teardown and fixturing cost:
Retest labor and overhead adder:

How to use the result

Use it after a hipot failure spike to quantify the rework hit, or when building a quality budget that anticipates a known failure rate.
It treats every failed motor as reworkable at the same cost; units that are actually scrapped, or faults that vary widely in repair effort, need a separate scrap line or a blended per-unit rate.

Current U.S. benchmarks

The producer price index for copper and brass mill shapes stands at 559.593 (BLS, May 2026), up 76.8% from a year earlier. Quotes priced off last quarter's material cost miss this move. Global copper trades at $13,484 per tonne (IMF via FRED, May 2026).
Steel mill PPI stands at 348.53 (BLS, May 2026), up 6.7% from a year earlier. New factory orders are up 2.3% year over year (Census).
The U.S. has 5,397 electrical equipment and appliances establishments employing about 369,437 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate rework cost from failed hipot? Multiply failed units by the rework cost per unit, then add the fixed teardown cost and the retest overhead adder. For 100 units at $2.50 each plus $75 fixed and $25 overhead, the total is $350.
What is the per-unit cost of hipot rework in this example? Dividing the $350 total by 100 failed motors gives $3.50 per reworked unit, which spreads the fixed $100 of teardown and overhead across the batch on top of the $2.50 direct repair.
When should I scrap a motor instead of reworking a hipot failure? Compare the per-unit rework cost against the motor's standard cost and its salvage value. If chasing an insulation breakdown approaches the build cost, or risks field reliability, scrap is usually the lower total-cost decision.
Why include a fixed cost and a separate overhead adder? The fixed cost covers batch-level setup like fixturing the rework cell, while the overhead adder captures retest labor and stand time. Separating them lets you see how much of the $3.50 per unit is truly avoidable versus structural.
What hipot failure rate makes rework cost a real problem? Even a few percent matters at volume. At $3.50 per reworked unit, a 5% fail rate on 10,000 motors is 500 units and $1,750 of rework, before counting the schedule disruption and any scrapped units.

Last reviewed 2026-05-12.