Coolant reaching a feedback system produces some of the most confusing faults on a machine. The axis trips at one position, runs clean at another, and behaves differently after a shift change. Green residue in a connector is not a rewind — it is a starting point, and the fault usually splits three ways. First:…
Out of warranty, the factory usually offers one thing: a complete spare. For a brand owner, that means buying the whole assembly when a board or a feedback device failed. A repair-return lane exists for that gap — and it works without taking the customer away from the brand. The after-sales problem When a brand…
The brake is a separate assembly from the motor, and it fails in two opposite directions. A brake that will not release makes the motor fight itself. A brake that will not hold lets a vertical axis drift. Both arrive at the maintenance desk described as a motor problem. A brake that will not release…
The board powers up. The motor turns. It also vibrates, and the current looks wrong on the meter. A repaired board is not the same thing as an aligned machine — and those two conditions are checked at different points in the job. Live is not aligned A board that is electrically sound can still…
When a replacement is weeks out, the repair-or-replace argument stops being about principle. It becomes a question of what is physically available this week, and what the machine costs while it waits. Availability decides — not a slogan about repairing everything. Stock general-purpose versus a special motor A general-purpose motor is a catalogue item. It…
Two questions decide this, and neither is about preference. Is a tested spare already on the shelf? And does the fault need work that cannot be done at the machine? Answer those and the route picks itself. Field swap is a speed decision Swap in the field when a tested spare exists and the machine…
An overcurrent alarm arrives looking like a verdict on the motor. It is not. A shorted winding, a jammed axis, a brake that will not release and a failed power stage in the drive all push current the same way, and they are fixed by different people. An OC alarm is not a rewind order…
The official spare for an EC unit is usually the complete module. That is how the parent sells it, and it is why a failed board becomes a purchase order plus a wait. The question worth answering first is narrower: is the fault in the electronics, and if it is, can the board be recovered?…
A brushless motor that locks and gets hot is often treated as a controller failure. Usually it is the commutation map. The Hall sensors tell the electronics where the rotor is, and when that information is wrong the drive still switches phases — just at the wrong moment. The result is heat, not torque. What…
The drive is in a position alarm. The shaft still turns by hand. Those two facts are not a contradiction, and they are the reason a motor should not be condemned on an encoder alarm alone. A feedback fault and a winding fault look similar on the HMI and behave nothing alike on the bench….
