ID HQ SERIES COIL [DW28490] [9"] ANGLE GRINDER SPARE PART [Makita Type] - 30375
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Restore Full Power — Genuine-Grade Coil Engineering for Your 9" Angle Grinder
The ID HQ Series Field Coil for 9" Angle Grinder (DW28490) is a precision-engineered Makita-type replacement coil designed to restore full power output to your angle grinder. Built with high-grade copper wire windings, premium insulation, and a laminated magnetic core, this power tool spare part (Part No. 30375) delivers reliable electromagnetic energy conversion, ensuring your grinder operates at peak efficiency after every repair.
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- Direct Makita-Type Replacement (DW28490 Compatible): Engineered as a drop-in replacement coil specifically matched to the DW28490 9" angle grinder platform. The dimensional tolerances, terminal configuration, and winding specifications are designed for compatibility with Makita-type motor housings, ensuring a straightforward, secure fit without modification.
- High-Grade Copper Wire Windings for Maximum Efficiency: The coil is wound using high-conductivity copper wire, minimising electrical resistance and heat build-up during operation. This translates to better power transfer from the power supply to the grinder's rotor, maintaining consistent RPM under load — critical for cutting, grinding, and surface preparation tasks.
- Laminated Magnetic Core for Reduced Energy Loss: The laminated steel core construction significantly reduces eddy current losses within the coil, allowing more electrical energy to be converted into usable mechanical energy rather than wasted heat. This improves overall tool efficiency and reduces thermal stress on the motor assembly.
- High-Temperature Resistant Insulation for Demanding Environments: The copper windings are coated with premium insulation rated to withstand the elevated temperatures generated during sustained angle grinder operation. This protects the coil from premature degradation, short circuits, and insulation breakdown, even in environments where the grinder is used intensively over extended periods.
- Genuine-Grade Quality Under Part No. 30375: Supplied under the HQ Series designation with part reference 30375, this coil is manufactured to meet or exceed the performance benchmarks of OEM field coils. It is a cost-effective repair solution that brings a worn or damaged 9" angle grinder back to full operational specification without the cost of a full tool replacement.
- Restores Motor Output and Prevents Further Mechanical Damage: A failing or failed field coil directly causes loss of power, erratic motor behaviour, excessive sparking, and in severe cases, total motor seizure. Replacing the coil promptly with this HQ Series unit stops further mechanical damage to the armature and motor housing, protecting the broader tool investment.
This HQ Series coil (Part No. 30375) is supplied as a single field coil unit intended for installation by a qualified power tool technician or experienced user. It is a genuine-grade aftermarket spare part and is not manufactured by or affiliated with Makita Corporation.
General Purchase & Comparison Queries
Is this coil compatible with my angle grinder?
This coil is specifically engineered for DW28490 9" angle grinders of the Makita type. If your grinder uses the same motor housing and terminal configuration as the DW28490 platform, this is a direct replacement. Always confirm your grinder's model number and existing coil part reference before purchasing. If in doubt, our team can assist with compatibility confirmation.
Is this an original Makita part or an aftermarket spare?
This is a high-quality aftermarket (HQ Series) spare part manufactured to meet or exceed the performance specifications of OEM coils. It is not manufactured by or affiliated with Makita Corporation. The HQ Series designation indicates it is produced to a genuine-grade standard, offering a reliable and cost-effective repair alternative to OEM parts.
Why should I replace the coil rather than buying a new angle grinder?
Replacing a failed field coil is significantly more economical than purchasing a new 9" angle grinder. The coil is one of the most common failure points in angle grinders due to heat and electrical stress over time. With a Part No. 30375 HQ Series replacement coil, you can restore your DW28490-type grinder to full operational specification at a fraction of the cost of a new tool, making it the smart choice for workshops, tradespeople, and repair technicians.
Product-Specific and Usage Queries
What does the field coil do in an angle grinder?
The field coil (stator coil) is responsible for generating a strong electromagnetic field within the motor housing. When electrical current passes through the copper wire windings wrapped around the laminated magnetic core, it produces this field, which interacts with the armature (rotor) to generate rotational mechanical energy — converting electrical energy from your power supply into the spinning force that drives the grinder disc.
Can I install this coil myself, or do I need a technician?
While an experienced power tool user with the correct tools may be able to replace the field coil, we strongly recommend installation by a qualified power tool repair technician. Angle grinder disassembly involves working with electrical components, and incorrect installation can result in motor damage, electrical hazards, or tool malfunction. Always disconnect the tool from the power supply before any internal work.
How do I know if my field coil has failed?
Common signs of a failed or failing field coil include significant loss of power output, the grinder running erratically or at inconsistent speeds, excessive sparking from the motor area, a burning smell from the motor housing, or the tool failing to start altogether. A technician can confirm coil failure using a multimeter to test coil resistance — an open circuit or reading significantly outside specification confirms the coil needs replacement.
Problem/Solution-Oriented Queries
My angle grinder has lost power — will replacing the coil fix it?
A degraded or partially failed field coil is one of the most common causes of power loss in angle grinders. If your DW28490-type grinder has progressively lost power, struggles under load, or runs at reduced speed, the field coil is a strong candidate for diagnosis. Replacing it with this HQ Series Part No. 30375 coil can fully restore motor output — provided the armature, brushes, and bearings are in serviceable condition.
My grinder is sparking excessively — could the coil be the cause?
Excessive sparking can result from worn carbon brushes, a damaged armature, or a deteriorating field coil with compromised insulation. When the coil's insulation breaks down, it can cause short circuits that increase brush sparking significantly. If brush replacement has not resolved the issue, the field coil should be tested for insulation resistance. Replacing it with this high-temperature resistant HQ Series unit may fully resolve the sparking.
Will this coil fit if my grinder is a different brand but uses the DW28490 spec?
This coil is designed for Makita-type DW28490 9" angle grinder motors. Many aftermarket and compatible-brand grinders use motor assemblies built to the same platform specification. If your grinder's motor housing, coil dimensions, and terminal positions match the DW28490 specification, this coil should fit. We recommend cross-referencing your existing coil's dimensions and part number, or consulting a qualified technician before installation.