Signs your servo motor needs rewinding
- The motor no longer holds position accurately under load.
- It runs hotter than usual during normal operation.
- There is a burning smell or visible discolouration on the windings.
- The feedback system reports position errors or the controller flags a fault.
- You notice unusual noise or vibration during operation.
- The motor draws higher current than its rated specification for a given load.
Because servo motors rely on a feedback loop between the motor and its controller, it is worth confirming the feedback device itself, such as an encoder or resolver, is functioning correctly before assuming the fault is in the windings.
How a servo motor works and why the windings fail
A servo motor is built to deliver precise control over position, speed, or torque, using a feedback device that continuously reports the rotor's actual position or speed back to a controller. The controller compares this feedback to the commanded position and adjusts current to the stator windings accordingly, correcting any difference in real time. This closed loop design is what allows a servo motor to hold a position accurately even under changing load, rather than simply running at a fixed speed.
Winding failure in servo motors is generally caused by the same core factors as other motor types, insulation breakdown from sustained heat, contamination from the operating environment, and mechanical stress on winding connections from continuous corrective adjustments under load. Because servo motors are often used in applications requiring frequent, rapid changes in torque, they can experience more thermal cycling than motors that run at a constant speed, which places extra demand on the winding insulation over time. A fault in the feedback device can also cause the controller to send incorrect current, placing uneven strain on specific windings.
What rewinding a servo motor actually involves
The stator is removed and stripped of its existing windings, then the core is checked carefully for lamination damage, since servo motors depend on tight tolerances to maintain accurate torque control. New wire is wound to the original manufacturer specification, matching turns count, wire gauge, and winding pattern precisely, since deviations here directly affect the motor's torque response and positional accuracy.
The stator is then insulated, dipped or impregnated with varnish, and cured to seal the windings in place. As part of the process we also check the feedback device, whether an encoder, resolver, or similar component, since a rewind on its own will not resolve a fault originating in the feedback system.
Once reassembled, the motor is tested with a compatible controller to confirm accurate position holding, correct current draw, and stable operation under load before it is returned.
Our rewinding and repair process
- Initial diagnosis of windings, feedback device, and controller behaviour.
- Full strip down and inspection of the stator core.
- Rewinding to the original manufacturer specification.
- Insulation testing and varnish curing.
- Reassembly and testing with a compatible controller and feedback system.
- Delivery or pickup coordination to suit your schedule.
Frequently Asked
Questions
Why is my servo motor not holding position accurately?
This can be caused by winding faults, a failing feedback device such as an encoder or resolver, or controller issues. We check all of these during assessment rather than assuming the windings alone are at fault.
Do you test the feedback device during a servo motor repair?
Yes, we check the encoder, resolver, or other feedback component as part of the assessment, since a rewind will not fix a fault originating in the feedback system.
How long does a servo motor rewind take?
Turnaround depends on motor size and winding complexity. Contact us for a current estimate based on your specific motor.
Can a servo motor be rewound to the same precision as the original?
Yes, provided the stator core is in good condition, we rewind to the original manufacturer specification to preserve the motor's torque and positional accuracy.
Your Local Auckland Based Motor Rewinder
When rewinding an electric motor, it is important to find a reliable service provider in order to ensure proper maintenance and repair of the equipment. A reliable service provider will have experience in the field, offering quality workmanship and specialized services.
They should also be licensed and certified, so customers have the assurance that they are dealing with a professional who meets industry standards. Finding a reliable service provider can help prevent damage or loss of equipment, saving time and money in the long run.
We proudly serve Auckland and the surrounding regions, including North Shore, East Auckland, West Auckland, South Auckland and Central Auckland.