ID HQ SERIES COIL [ID AGH125B] [G15SA2] [5"] ANGLE GRINDER SPARE PART [Makita Type] - 30131
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Restore Full Power — Precision-Wound for Maximum Motor Efficiency
The ID HQ Series Field Coil [ID AGH125B] [G15SA2] is a premium-grade 5" angle grinder spare part engineered as a direct replacement for Makita-type angle grinders. Crafted with precision copper wire windings, high-grade insulation, and a robust magnetic core, this field coil delivers reliable electromagnetic energy conversion to restore your tool's full power output. Part number 30131 ensures a verified OEM-compatible fit for fast, confident repairs.
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- OEM-Compatible Design for Makita AGH125B: Engineered to the exact dimensional and electrical specifications of the Makita-type AGH125B 5" angle grinder, this field coil slots in without modification, eliminating guesswork and reducing repair time significantly in workshop environments.
- Copper Wire Windings for Superior Conductivity: The coil is wound with high-purity copper wire, chosen for its low electrical resistance and excellent thermal conductivity. This ensures minimal energy loss during operation, translating to consistent torque output and cooler running temperatures under load.
- High-Temperature Resistant Insulation: The winding insulation is rated for the elevated temperatures generated during prolonged grinding sessions. This heat-resistant coating prevents insulation breakdown — one of the most common causes of coil failure in angle grinders used for cutting, grinding, and surface preparation.
- Robust Magnetic Core for Stable Electromagnetic Field: The laminated magnetic core is designed to minimise eddy current losses while maintaining a strong, stable electromagnetic field. This directly contributes to efficient mechanical energy conversion, keeping RPM consistent even under variable load conditions.
- HQ Series Build Quality — Part No. 30131 [G15SA2]: Part of the ID HQ (High Quality) Series, this coil undergoes stricter manufacturing tolerances compared to standard aftermarket parts. The G15SA2 specification code and part number 30131 make sourcing, cross-referencing, and warranty tracking straightforward for trade buyers and repair professionals alike.
This field coil is supplied as a single replacement coil unit (Part No. 30131) ready for installation. It carries the ID HQ Series quality designation, which reflects compliance with elevated manufacturing standards for aftermarket power tool components — making it a dependable choice for professional repair technicians and service centres working with Makita-compatible 5" angle grinders.
General Purchase & Comparison Queries
Is this coil compatible with my Makita angle grinder?
This ID HQ Series Field Coil (Part No. 30131) is specifically designed as a Makita-type compatible spare part for the AGH125B 5" angle grinder model, referenced under specification code G15SA2. We recommend cross-referencing your grinder's model number and original part number before ordering to confirm fitment. If you are unsure, please contact us with your tool's model details.
How does the ID HQ Series coil compare to the original OEM part?
The ID HQ (High Quality) Series is manufactured to elevated aftermarket standards, using high-purity copper wire windings, heat-resistant insulation, and a precision laminated magnetic core. While it is an aftermarket replacement rather than a Makita-branded part, the HQ Series designation reflects stricter tolerances than standard aftermarket alternatives, offering a reliable, cost-effective solution for professional repairs.
Can I use this coil for other angle grinder brands or models?
This field coil is engineered specifically for Makita-type AGH125B 5" angle grinders. Whilst some third-party grinders share similar architectures, we strongly advise against fitting this coil into models it was not designed for. Incorrect installation can result in motor failure, overheating, or safety hazards. Always verify the part number 30131 and specification code G15SA2 match your tool's requirements.
Product-Specific and Usage Queries
What causes a field coil to fail in an angle grinder?
Field coil failure in angle grinders is most commonly caused by overheating due to sustained heavy loads, insulation breakdown from prolonged use, voltage spikes, or physical damage from impact. Symptoms include the tool running intermittently, producing a burning smell, losing power, or failing to start. Replacing the field coil (Part No. 30131) with this HQ Series unit restores the grinder's electromagnetic function and full power output.
Do I need any special tools to install this field coil?
Installation requires basic power tool disassembly skills and standard workshop tools including screwdrivers, spanner sets, and a coil puller where applicable. It is recommended that this replacement be carried out by a qualified power tool technician or experienced repair professional to ensure correct fitment, proper winding orientation, and safe reassembly. Always disconnect the tool from the power supply before beginning any repair.
What is the role of the magnetic core in this field coil?
The laminated magnetic core within this field coil serves to concentrate and direct the electromagnetic field generated by the copper wire windings. By minimising eddy current losses, the core ensures efficient conversion of electrical energy into mechanical energy, maintaining consistent rotor speed (RPM) and torque output. This is critical for stable performance during demanding cutting and grinding applications.
Problem/Solution-Oriented Queries
My angle grinder has stopped working — could the field coil be the problem?
A failed field coil is one of the most common causes of a complete angle grinder failure. If your Makita AGH125B has stopped running, runs erratically, produces a burning odour, or shows signs of overheating, the field coil should be among the first components inspected. A multimeter test across the coil terminals can identify an open circuit or a short to ground. Replacing the coil with this ID HQ Series Part No. 30131 is a cost-effective repair compared to replacing the entire tool.
The grinder runs but lacks power — can a worn coil cause this?
Yes. A partially degraded field coil with damaged insulation or weakened windings can still allow the tool to run but with significantly reduced power and torque. This often manifests as the grinder bogging down under light loads, running hotter than usual, or taking longer to reach operating speed. Installing a fresh HQ Series field coil (Part No. 30131) restores the full electromagnetic field strength, bringing the motor back to its rated performance.
How do I avoid premature coil failure after replacement?
To maximise the service life of your new ID HQ Series field coil, avoid sustained operation at maximum load for extended periods without allowing the tool to cool. Ensure the grinder's ventilation slots are kept clear of dust and debris to maintain adequate airflow around the motor. Use the correct disc size and type specified for the AGH125B model, and avoid stalling the motor under excessive pressure. Regular inspection of brushes and the armature will also help detect issues before they cause secondary coil damage.