ID HQ SERIES COIL [GA7020] [GA9020] [7"] ANGLE GRINDER SPARE PART [Makita Type] - 30378
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Restore Full Power. Rebuild Smarter. Built to Last.
The ID HQ Series Field Coil is a precision-engineered replacement coil spare part designed for Makita-type 7-inch angle grinders, specifically compatible with models GA7020 and GA9020. Built with high-grade copper wire windings, a robust magnetic core, and advanced thermal insulation, this power tool coil delivers reliable electromagnetic performance and efficient energy conversion, restoring your grinder to full operating capacity with minimal downtime.
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- Direct Compatibility with GA7020 & GA9020: This field coil is specifically engineered to match the internal dimensions and electrical specifications of Makita-type 7-inch angle grinders (models GA7020 and GA9020), ensuring a secure fit, proper alignment, and immediate operational restoration without custom adaptation.
- High-Grade Copper Wire Windings: The coil is wound with precision-grade copper wire that offers excellent electrical conductivity, minimising resistance losses and heat build-up during prolonged operation — critical for tools running continuous grinding, cutting, or surface preparation tasks.
- Advanced High-Temperature Insulation: The multi-layer insulation system surrounding the windings is rated for sustained high-temperature environments, protecting the coil from thermal degradation even under demanding conditions such as prolonged heavy grinding or repetitive load cycles.
- Optimised Magnetic Core for Efficient Energy Conversion: At the heart of this coil is a laminated magnetic core designed to maximise electromagnetic flux and minimise eddy current losses, translating directly into stronger motor torque, stable RPM output, and reduced energy waste during operation.
- OEM-Specification Replacement Part — Part No. 30378: Manufactured to original equipment manufacturer specifications, this coil (part number 30378) is a like-for-like replacement that restores the grinder to factory performance standards, making it the preferred choice for professional repair technicians and tool service workshops alike.
This coil is supplied as a complete field coil assembly ready for installation, and is backed by ID HQ Series quality standards to ensure consistent performance across all compatible Makita-type angle grinder platforms.
General Purchase & Comparison Queries
Is this coil compatible with my Makita GA7020 or GA9020 angle grinder?
Yes. The ID HQ Series Field Coil (Part No. 30378) is specifically designed for Makita-type 7-inch angle grinders, including the GA7020 and GA9020 models. It is built to OEM specifications for a direct, drop-in replacement with no modification required.
How does this replacement coil compare to an original Makita coil?
The ID HQ Series coil is manufactured to OEM-equivalent specifications, using high-grade copper wire windings and a laminated magnetic core that mirrors the performance of the original part. It offers a cost-effective alternative to purchasing a brand-new tool while maintaining the same power output, torque characteristics, and thermal resistance.
Is it more economical to replace the coil or buy a new angle grinder?
In most cases, replacing the field coil is significantly more economical than purchasing a new grinder. A burned or damaged coil is one of the most common causes of grinder failure, and swapping it out with a quality replacement like the ID HQ Series Part No. 30378 restores full functionality at a fraction of the cost of a new machine — making it the preferred choice for professional workshops and contractors.
Product-Specific and Usage Queries
What is the function of a field coil in an angle grinder?
The field coil is a critical motor component responsible for generating the electromagnetic field that drives the armature (rotor) of the angle grinder. It consists of copper wire windings wound around a laminated magnetic core, converting electrical energy into a rotating magnetic field that produces the mechanical torque needed for grinding, cutting, and surface preparation tasks.
Can I install this coil myself, or do I need a professional technician?
This coil is designed as a direct OEM-spec replacement, making installation straightforward for anyone with basic power tool repair experience. However, working on the internal motor components of power tools involves electrical components, so it is recommended that installation be carried out by a qualified power tool repair technician to ensure safety and correct reassembly.
How do I know if my angle grinder's field coil needs replacing?
Common signs of a failing or burned field coil include loss of power or reduced RPM, the grinder failing to start, unusual burning smells, visible scorch marks on the motor windings, or the tool tripping circuit breakers repeatedly. If your GA7020 or GA9020 exhibits any of these symptoms, the field coil is a primary suspect and should be inspected and replaced with the ID HQ Series Part No. 30378.
Problem/Solution-Oriented Queries
My angle grinder has lost power and runs slowly — can a new coil fix this?
Yes, in many cases a degraded or partially burned field coil is the direct cause of reduced power and sluggish RPM in angle grinders. When the copper wire windings suffer insulation breakdown or partial short-circuits, the electromagnetic field weakens, resulting in noticeably reduced torque. Replacing it with the ID HQ Series Field Coil (30378) will restore the full electromagnetic output and bring your GA7020 or GA9020 back to peak performance.
My grinder overheats quickly — is the coil the problem?
Excessive heat build-up is often linked to insulation failure in the field coil, which causes increased electrical resistance and energy loss as heat rather than mechanical output. The ID HQ Series coil features high-temperature resistant insulation designed to withstand sustained heavy-duty operation, helping to prevent premature thermal failure and keeping your grinder running cooler for longer.
The grinder works intermittently and cuts out under load — is this a coil issue?
Intermittent operation and cut-outs under load are classic symptoms of a failing field coil with partial winding damage. As the coil heats up under load, compromised insulation breaks down further, causing the motor to lose continuity temporarily. Replacing the coil with the ID HQ Series Part No. 30378 — which is built with robust copper windings and a high-integrity insulation system — will eliminate this fault and restore consistent, reliable performance to your Makita-type GA7020 or GA9020.