IDEAL ARMATURE HQ SERIES [GSH388] ROTARY HAMMER DRILL SPARE PART [GENERIC] [Bosch Type] - 26678

Engineered to Perform. Built to Last. Restore Your Rotary Hammer to Full Power. The Ideal Armature HQ Series [GSH388] is a high-performance, generic replacement armature engineered to the Bosch GSH388 specification (Part No. 26678). Built with 100% pure copper windings and a precision multi-segment commutator, this heavy-duty spare part restores full power and efficiency to your rotary hammer drill, delivering industrial-grade longevity at a fraction of OEM cost. Ideal for professional repair technicians and workshop maintenance teams who demand reliable, cost-effective power tool restoration. Key Features Perfect For 100% Copper Windings — High-purity copper ensures maximum electrical conductivity and superior heat resistance under heavy-duty cycles Professional Power Tool Repair — Ideal for technicians servicing Bosch GSH388-type rotary hammer drills in workshops and on-site Precision Multi-Segment Commutator — Engineered for smooth current transfer from carbon brushes, minimising sparking and brush wear Industrial Maintenance Programs — Perfect for facilities running scheduled preventive maintenance on heavy-duty drilling equipment Resin-Coated, Laced Windings — Reinforced winding structure withstands the extreme centrifugal forces generated by professional-grade motors Cost-Effective Tool Restoration — A smart alternative to full tool replacement, extending the service life of existing equipment Heavy-Duty Magnetic Core — Precision-engineered magnetic core ensures efficient energy conversion from electrical to mechanical output Construction & Demolition Sites — Suited for environments where rotary hammer drills are subjected to continuous, high-load operation Drop-In Bosch-Type Compatibility — Manufactured to Bosch GSH388 dimensions (Part No. 26678) for a direct, hassle-free fitment Spare Parts Stockists & Distributors — An essential stock item for power tool spare parts retailers serving the professional trades market Bosch GSH388 Direct-Fit Compatibility (Part No. 26678): This armature is manufactured to the precise dimensional and electrical specifications of the Bosch GSH388 rotary hammer drill, ensuring a direct drop-in replacement with no modifications required. The shaft diameter, overall length, commutator segment count, and winding resistance are all matched to OEM tolerances, guaranteeing correct fitment and immediate operational readiness upon installation. 100% High-Purity Copper Winding Construction: Unlike armatures wound with aluminium or copper-clad wire, the HQ Series uses solid, high-purity copper conductors throughout the winding stack. Copper's superior electrical conductivity (approximately 59.6 × 10⁶ S/m) means lower resistive losses, less heat generation at equivalent load, and a significantly extended thermal lifespan — critical in the sustained, high-current draw environment of a rotary hammer motor. Precision Multi-Segment Copper Commutator with Minimal Runout: The commutator is machined from solid copper bar stock and features multiple segments with tight inter-segment insulation. This design ensures consistent, low-resistance contact with the carbon brushes across the full rotation cycle, dramatically reducing electrical arcing, brush wear, and the associated carbon fouling that degrades motor performance over time. Resin-Impregnated and Laced Winding Structure for Centrifugal Stability: At the high RPM levels generated by professional rotary hammer motors, centrifugal forces place enormous stress on winding conductors. The HQ Series armature addresses this with a dual-protection system: the windings are first mechanically laced with high-tensile thread to lock conductors in place, then the entire assembly is vacuum-impregnated with a high-temperature thermosetting resin. This creates a rigid, monolithic winding block that resists vibration, moisture ingress, and thermal cycling fatigue. Balanced Rotor Assembly for Vibration-Free Operation: Each armature in the HQ Series undergoes dynamic balancing of the rotor assembly. An unbalanced armature introduces destructive vibration into the tool's bearing set and gearbox, accelerating wear across multiple components simultaneously. By ensuring the rotating mass is correctly balanced, this armature protects the wider drivetrain and delivers the smooth, controlled power delivery that professional users depend on for precision drilling and chiselling work. Industrial-Grade Laminated Core for Reduced Eddy Current Loss: The magnetic core is constructed from a stack of thin, electrically insulated silicon-steel laminations rather than a solid iron core. This laminated architecture dramatically reduces eddy current losses — parasitic electrical currents induced within the core by the alternating magnetic field — converting more of the input electrical energy into useful mechanical torque and generating significantly less waste heat during operation. General Purchase & Comparison Queries Is this a genuine Bosch armature or a generic replacement? This is a high-quality generic (aftermarket) replacement armature, not an original Bosch OEM part. It is engineered to the Bosch GSH388 specification (compatible with Part No. 26678) and manufactured to match OEM dimensions, winding resistance, and commutator geometry. The Ideal HQ Series is designed to deliver equivalent or better performance than the original in terms of conductivity and durability, at a significantly more accessible price point — making it the preferred choice for professional repair workshops and cost-conscious maintenance teams. Which specific Bosch rotary hammer models is this armature compatible with? This armature is designed as a direct replacement for Bosch GSH388-type rotary hammer drills, corresponding to Bosch spare part number 26678. If you are unsure whether your specific model is compatible, we recommend cross-referencing your tool's model number and the existing armature's part number before purchasing. You can also contact our team with your tool's model plate details and we will confirm compatibility for you. Why should I choose an aftermarket armature over an OEM part? Aftermarket armatures from the Ideal HQ Series offer a compelling value proposition for professional users. The 100% copper winding construction and resin-impregnated, laced winding structure are features that match or exceed the build quality of many OEM components. The primary advantage is cost efficiency — you can restore a professional-grade rotary hammer to full working condition at a fraction of the cost of an OEM part or a tool replacement, without compromising on performance or longevity when the repair is carried out correctly. Product-Specific and Usage Queries What is included in the package and what tools do I need for installation? Each order includes one (1) complete HQ Series armature unit, comprising the fully wound and resin-impregnated rotor, the machined multi-segment copper commutator, and the precision-ground output shaft — everything needed for a direct installation. Installation requires standard power tool disassembly tools (typically a set of Torx and Phillips screwdrivers, snap-ring pliers, and a soft-faced mallet). We strongly recommend that armature replacement be carried out by a qualified power tool repair technician to ensure correct fitment and safe operation. Why are 100% copper windings important in an armature? Copper is the benchmark conductor for electric motor windings due to its exceptional electrical conductivity — significantly higher than aluminium alternatives. In a rotary hammer armature, this translates directly to lower resistive losses, meaning more of the electrical energy drawn from the mains is converted into useful rotational torque rather than waste heat. This keeps the motor running cooler during sustained heavy-duty use, which is the single most important factor in determining the long-term lifespan of the armature and the carbon brushes that contact it. How do I know if my rotary hammer's armature needs replacing? Common symptoms of a failing armature in a rotary hammer drill include: significant loss of power or torque that cannot be attributed to worn carbon brushes; excessive sparking visible at the brush contact area during operation; a burning smell emanating from the motor housing; the tool running intermittently or cutting out under load; or the motor failing to start despite the brushes and power supply being confirmed as functional. If you observe any of these signs, a visual and electrical inspection of the armature — including a commutator continuity check — is the recommended next diagnostic step. Problem/Solution-Oriented Queries My rotary hammer is producing excessive sparking — will replacing the armature fix this? Excessive sparking at the brush contact zone is one of the most common indicators of commutator wear or damage. Over time, the commutator segments can become grooved, pitted, or contaminated with carbon deposits, preventing the brushes from making clean, consistent contact. The Ideal HQ Series armature features a precision-machined, multi-segment copper commutator designed for smooth, low-resistance brush contact — directly addressing this root cause. However, it is also advisable to replace the carbon brushes simultaneously, as worn brushes on a new commutator will accelerate wear on the fresh surface. If sparking persists after replacement, the issue may lie with the field coil or power supply. My rotary hammer is overheating during use — can a new armature resolve this? Overheating in a rotary hammer motor is frequently caused by increased winding resistance due to partial winding failure or insulation breakdown in the armature. A degraded armature draws more current to produce the same output, generating excess heat in the process. Replacing it with the Ideal HQ Series armature — with its high-purity copper windings and resin-impregnated insulation system — restores the motor to its correct electrical resistance profile, reducing current draw and heat generation. Additionally, ensure the tool's ventilation slots are clear of dust and debris, as blocked airflow is a common contributing factor to overheating independent of armature condition. The tool runs but has lost significant power — is the armature likely the cause? A noticeable reduction in power output — where the tool runs but feels sluggish or struggles under load — can have several causes, but a partially failed armature is a primary suspect. If one or more winding groups have developed an open circuit or a short to the core, the motor will continue to run on the remaining healthy windings but with reduced torque and efficiency. Before replacing the armature, it is worth first ruling out worn carbon brushes (a simpler and cheaper fix) and a faulty field coil. If brushes are within service life and the field coil tests correctly, replacing the armature with the Ideal HQ Series [GSH388] is the logical next step to restore full performance.