How to disassemble the gearbox of a Makita 9565 angle grinder
Recommendations for repressing planetary gears angle grinder (grinders)
There is on the secondary market such an angle grinder as Fiolent MSHU 2-9-125, which has a planetary pinion ?hot? fit on the spindle shaft. The tension and force is nominal, but in the experience of the online store, too much demand for the gear housing flange. Fiolent is famous for low unification, but that at each presser to buy the ORIGINAL flange for about 5 (for a piece of cast aluminum, machined on the lathe and a maximum of a milling machine). Little value, and even a scarce part, which prompted me to give birth to this post.
Seating with guaranteed interference (hot). no slack fit planetary pinion (large/slave), inner diameter of which is less than the shaft diameter (difference of about 0,05. 0.4 mm). This fit provides a reliable, no-play fixation of the pinion on the shaft, guaranteed to withstand radial loads during operation of the angle grinder. As a rule, this type is inherent in the tools of the professional class, but today’s market has mixed the concepts and made the technology available even in the tools of the DIY class.
Pressing the planetary pinion
To begin the process logically, let’s look at the reasons why you need to press the assembly:
Any competent repair, involves replacing only the damaged parts, conducting a preliminary defectoscopy of the tool as a whole. With high probability, we preliminarily exclude unprofitable actions. If unprofessional approach, pressing out the assembly, we risk the spindle shaft and gearbox housing flange (as practice shows, not an uncommon occurrence)
- The preliminary step will be the “soaking” landings deep penetrating grease (WD-40 ideally / or any analogue) for at least 10 minutes, it will not make worse.
- Some shafts have a groove and a retaining ring. do not forget to remove them (in a good press, even with a retaining ring, you can pull the pinion, but the fit will be lost)
- Preparing the inserts. CRITICAL STEP
- Thrust. Any shafts have turning centers. To minimize distortion, work with. For the spindle it is best to use a ball (can be taken from an old bearing). The diameter of the ball depends on the diameter of the top of the shaft. Too large a ball can roll off the thin end of the shaft (we’ve had a few cases in the shop). Try the ball on to the center of the shaft beforehand. the stop should be firm, meaning about 1/3 of the ball goes into the cone of the center.
- Working. Here’s where practice shows the main causes of trouble! As a rule, you can find a socket head or a piece of pipe of suitable diameter and height in the workshop, but. Requirement for the set: Parallelism of the set faces (otherwise misalignment is inevitable). The inside diameter of the sleeve allows the shaft to pass effortlessly through the hole; the wall thickness is sufficient for stiffness (3 mm). The wall must clearly rest against the reinforced part of the gear housing flange (stop in the mounting holes of the flange. a risky undertaking (the thickness may not allow weighty loads and corners are likely to break out. There have been cases in our practice). If the emphasis is made in the anther of the support bearing. A deliberate decision to neglect the dust cover in favor of saving the expensive flange. A combined/combined set / combination set is permissible, whereby each component is properly supported and fulfils the above requirements, but a single-piece set is the best choice.
Design and wiring diagram of an angle grinder
Over the many years of the existence of the angle grinder, its appearance as well as the inner workings have remained practically unchanged. To repair the angle grinder with your own hands, you need to know the structure of its mechanical part, as well as the electrical.
If you look at the illustration below, you can see what parts make up an angle grinder.
- Wheel for adjusting the machine’s spindle rim.
- The electric motor, consisting of the rotor and stator.
- Trigger Button. Sometimes a soft starter system is connected to it.
- Shatterproof plastic housing.
- Button for locking the spindle (used for tool changes).
- Safety overload clutch. Prevents the motor from overloading if the tool jams.
- Protective cover. Covers the tool and protects the user from flying particles of the material being machined and also prevents personal injury if the tool, such as an abrasive disc, is destroyed.
- Nut that clamps the tool. Unscrewing with the special key included in the box with the power tool. There is also a quick-clamping nut that can be unscrewed without a wrench.
- Gearbox case and gearbox itself. Consists of a set of gears that transmit the rotary motion from the rotor to the spindle with the tool.
The diagram below shows an electrical diagram of an angle grinder.
The electrical part of the angle grinder has the following elements
- The electric cable with plug for connecting to the mains;
- Start button;
- Electrical brushes (carbon or graphite);
- Armature (rotor).
The following figure shows the connection diagram of the angle grinder, namely its motor.
All parts of the electric motor have a specific function.
- The rotor is the shaft on which the coils and the collector are placed. The rotor, rotating in the magnetic field of the stator, transmits rotary motion to the gearbox angle grinder.
- Collector. It is the part of the rotor to which all the control cables are routed. Electrical signals from the control box go through the collector to the motor. It is the collector to which the electric brushes are connected.
- Electric brushes. Their main task is to transmit the electric current from the power cable to the collector.
- Stator. is a coil with a defined number of windings. The task of the stator is to generate a magnetic field which interacts with the armature and sets the latter in motion.
Lubricating an angle grinder to make it work better
Advice! Specialists do not recommend the use of materials such as solidol and lithium grease.
Deciding what to lubricate the angle grinder, pay extra attention to materials based on silicone or silicone oil. These greases are well suited for tools that operate in the speed range from slow to high and for all loads. They are highly resistant to oxidation, protect against corrosion, easy to mix with plastics and elastomers. Only silicone and lithium thickener are used, which makes them non-hazardous from an environmental point of view. Maintains consistency at temperatures from.50 to 190 degrees Celsius.
One of the most important components of the angle grinder. it’s gearbox. It gets very hot when the tool is running, because the gears are rotating behind it, which causes a lot of heat. Specifically for these reasons, the gearbox casing is made of metal, because it rather quickly removes heat. But the 1-th housing is not enough to cope with high temperatures, its proper lubrication is also of great importance.
Who is a specialist on the question of what to lubricate the gear reducer angle grinder, will answer that it is preferable to use a special grease for angle grinder. It is specifically designed for the work and criteria in which such tools are used. This grease has a specific blue color. An excellent, high-quality gear lubricant for angle grinders has the following designation: MoS2 NLGI 5 ISOL-XBCHB 2 DIN 51825-KPF 2.4 K-20. Marking means:
- MoS2. the additive is molybdenum disulfide;
- NLGI 3.2. 2nd viscosity grade;
- ISOL-XBCHB 5. compliance with ISO standards;
- DIN 51825-KPF 5 K-20. the most important point; it means the grease conforms to German DIN standards.
- 51825 indicates that it is a K grease.
- K. designed for plain bearings;
- P. with anti-seize additives;
- F. With a hard filler;
- 4. the mixture complies with NLGI;
- K. highest operating temperature of 120 degrees Celsius;
- 20. low temperature of operation.
Note! Implementation of special greases for angle grinder will give the highest guarantee of reliable operation.
Particular attention should be paid to the lubrication of grinders, which are under warranty. Without the help of others to do it is not recommended, you should entrust this work a special shop. High quality, unique materials will be used there with the correct dosage. You can apply the consistency incorrectly with your own hands, which will affect the longevity of the tool.
Tip! In a special service is recommended to give not only the angle grinder under warranty, but those at which the warranty period has passed.
Lithol and solide for gear and bearing lubrication is strictly prohibited. Even more, opening the housing on warranty tools will be a prerequisite for refusal of service, and the introduction of “unauthorized” grease in general is the worst violation of the rules of operation of angle grinder. The only exceptions are the outer components, which according to the manual should be processed often.
angle grinder, as well as other tools used in household and professional activities, requires constant maintenance. Efficient operation and long service life due to timely maintenance.
Angle grinder lubricant. a key component for equipment maintenance. In order to increase performance, the right grease composition should be selected.
The main modular unit of the angle grinder is the gearbox. It bears the brunt of the load during operation. It consists of helical gears that transmit the torque from the rotor to the driven element. Lubrication of angle grinder gears ensures reduction of friction forces in the gears. It also contributes to lowering the temperature that occurs during operation.
Where to change the lubricant? In due course of time, the lubricant layer spills out around the gear unit housing. It dries out after a short period of time and clumps form. Clumps of course accumulate particles of dust and metal formed during the work. If the disassembly of the angle grinder, found lumps, then you need a new grease for the gearbox angle grinder.
There are situations when you want to change the details of the gearbox angle grinder or otherwise the rotor bearing. In this case, the unit must be disassembled. The lubricant layer is accordingly removed. New material is applied in its place.
During long periods of work, the gearbox of the angle grinder heats up. Accordingly, the coating used also begins to heat up. When hot, the lubricant becomes watery and can leak out. When finished, not enough of it remains inside. This is caught by looking around the gears. They should have a thick layer. Thus, if the volume of the lubricating coating is small, it must be replaced.
Lubricating coating for gears is characterized by the following qualities:
- Viscosity not exceeding 800 Pas;
- droplet drop temperature at least 120°C;
- Tensile strength of at least 120 Pa;
- absence of mechanical impurities;
- resistance to corrosion;
- the highest melting point;
- water repellency.
Choose a lubricant that does not promote seizure in the areas of contacting parts.
When choosing coatings, it is necessary to take into account that lubricating grease of gearbox bearing parts is different from lubricating grease of engine bearings.
Many people wonder what to grease a gearbox of an angle grinder in order not to destroy the tool and increase its efficiency. The following types of greases are possible:
Probably the tool builders strictly recommend to use the right grease for maintenance in order to avoid negative consequences during the operation. When using a compound of other manufacturers tool is not subject to warranty repair.
Many people will think that it is very expensive to lubricate the gearbox with the manufacturer’s compound. After all, the price of such materials is quite high. Even today, there are Russian automakers that do not produce lubricants.
Choosing for himself a solidol as it is also called lithol as a lubricant, there is a risk to lead the tool to a sharp breakdown. This is justified by the fact that these substances do not imply use at high temperatures and high friction. That’s why after a while there are problems with the tool during its operation.
The tool required for repair
Repairing a Makita angle grinder with your own hands requires the use of certain tools. You can’t do without a set of screwdrivers. Preferably, they should be equipped with a ratchet mechanism. The best option is to use a cordless electric screwdriver. To repair the electrical part of the angle grinder Makita, you will need a tester, a device for determining short-circuited turns IK-2. Also prepare an open-jaw wrench, bearing extractors, a hammer, a soft metal bit. Well, do not do without the right grease, wiping supplies, liquids to wash off the old grease.
Start the repair of the angle grinder with your own hands should be with the preparation of the workplace, install the correct lighting. You will need a diagram of the angle grinder needed model and the proposed instructions.
Any faults of power tools are divided into two types: electrical and mechanical.
Consider the repair of nodes angular grinder Makita will be on the example of the circuit file angular grinder Makita 9565.
Possible electrical problems
Electrical malfunctions of a Makita angle grinder can be divided into control circuit malfunctions, rotor malfunction, and stator malfunction.
How to troubleshoot the control circuits of a Makita angle grinder
If your Makita angle grinder does not turn on, the greatest cause may be a breakdown in the power and control circuits.
To get to the control circuit components you need to remove the rear enclosure cover pos.38 by unscrewing the self-tapping screw pos.39. Switch ST115-40 K9565 pos.28 attached in the switch holder pos.27. The switch holder is closed by cover pos.29 which is secured to the motor housing pos.33.
The power cable is connected to the switch pos.37. Use a tester to check the continuity of the circuits from the plug contact to the switch terminals. Switch pos.28 is controlled by the lever pos.30. From the switch contacts, check the circuit to the carbon brushes pos.42.
The weakest link in the control circuits is the carbon brushes. The Makita 9565 angle grinder uses CB-318 carbon brushes with auto-off, so check the brushes.
Professional lathes are equipped with speed controllers. Makita angle grinders over 1000 watts have a soft start system. The Makita 9077SF angle grinder is equipped with this system.
If the switch fails, the problem can be eliminated by replacing it completely. If the power lead is broken or interrupted, the problem can be repaired by replacing the entire lead or by removing the damaged parts.
The switch-on process is accomplished with the lever pos.30. If you disassemble the angle grinder body for repair or service, lubricate the slots in the lever movement with silicone grease before reassembling.
Possible electrical faults
Electrical faults on a Makita angle grinder can be divided into control circuit faults, rotor faults, and stator faults.
How to troubleshoot the control circuits of a Makita angle grinder
If your Makita grinder does not turn on, the greatest cause may be a breakdown in the power and control circuits.
To get to the control circuit components you need to remove the rear enclosure cover pos.38 by unscrewing the self-tapping screw pos.39. ST115-40 K9565 switch pos.28 is fastened in the switch holder pos.27. The switch holder is covered with a cover pos.29, which is attached to the motor housing pos.33.
The power cord, pos.37. Using a tester, check continuity of circuits from plug contact to switch terminals. Switch pos.28 is operated by the lever pos.30. Check the circuit from the switch contacts to the carbon brushes pos.42.
The weakest link in the control circuits is the carbon brushes. The Makita 9565 angle grinder uses CB-318 carbon brushes with auto-off switch, so check the brushes.
Professional lathes are equipped with speed controllers. Makita angle grinders over 1000 watts have a soft-start system. Such a system is equipped with a Makita 9077SF angle grinder.
At failure of the switch the defect is eliminated by its complete replacement. If the power supply wire is broken or broken, the problem can be solved by replacing the entire wire or by removing the damaged parts.
The activation process is carried out with the lever pos.30. If you disassemble the angle grinder body for repair or service, grease the movement of the lever with silicone grease before reassembling.
Checking the motor
In addition to the control circuits, the electrical circuitry of the angle grinder includes the rotor and stator. These are complex units, which repair is recommended to perform in specialized centers. But nothing is unavailable for Russian craftsmen. We recommend ours.
How to repair the stator of a Makita angle grinder
At failure of stator pos.24 angle grinder indicates the appearance of burning odor, overheating of the housing angle grinder, spontaneous dialing speed angle grinder. In the body of the angle grinder pos.33 the stator is fastened with four 4×70 self-tapping screws pos.21. To prevent damage, the stator is covered with the stator guard pos.20.
Repairing the stator of a Makita angle grinder consists of determining if the windings are shorted or broken. It is best to carry out a stator diagnosis with a special tool called the EC-2. The stator is considered defective if you can see traces of darkening of the winding, a breakage or short circuit of the winding turns is detected.
How to repair the rotor of a Makita angle grinder
If the angle grinder overheats, if there is a smell of burning, an increase in sparking around the manifold, pay attention to the integrity of the rotor pos.13.
Diagram of a Makita angle grinder
Disassembling the rotor involves performing a sequential disassembly. To remove the rotor, release it from the gearbox pos.3. To do this, unscrew the hex nut M6 pos.4. To unscrew the nut, you have to clamp the rotor with one hand. With the other hand, using an open-end wrench, unscrew the counterclockwise nut.
Remove the nut, pull out the flat washer pos.5, remove conical spiral pinion pos.6, remove retaining spring pos.7. While rocking the rotor gently pull it out of the gearbox housing pos.3. Having removed the circlip pos.8, use a puller to remove the bearing, pos.9.
The Makita 9565 angle grinder uses a 6001LLB bearing.
It remains to remove the flat washer pos.10 and gearbox cover pos.11.
You are looking at the rotor of the Makita 9565 angle grinder with the insulating washer, pos.14, with a flat washer pos. 7.15, bearing pos.16 and the rubber dust cap 22 pos.17. The angle grinder uses a 627zz bearing on the manifold side. Russian equivalent 80027.
Repair the rotor by replacing it with a new or repaired one. You can repair the rotor yourself, but you need not only patience, equipment, material. It’s the kind of high-end work.
Makita 9565CVR spare part diagram
On this page you can pick up and buy original parts for Makita 9565CVR angle grinder angle grinder parts. spindle, nut, flange, protective sleeve, gear housing, motor housing, lock button, bevel gear, armature (rotor), stator, carbon graphite brushes, brush holder, bearing, shock absorber, button, linkage. Makita 9565CVR angle grinder parts have photos, price, description, reviews. To select to order order to buy parts Makita 9565CVR. select in the product list adjacent to the diagram the part that corresponds to the part number in the diagram and click on its name.
|1, 2, 58, Locking button3 Gear housing 9565CVR4 Hexagon nut M65 Washer 66 Drive pinion 9565CVRCone pair 9565CVR7 Locking spring 9565CVR8 Safety ring S- 129 Ball bearing 6001LLB10 Washer 1211 Gear case cover12 Impeller 9565CVR13 Anchor 9565CVR and Anchor equivalent14 Insulating pad15 Washer 716 Ball bearing 627DDW17 Bearing shock absorber 9565CVR18 Clamping washer 619 Magnetic coupling 9565CVR20 Lock washer 621 Fairing22 Self-tapping screw 4×7023 Holder24 Insulating cap25 Stator 9565CVR26 Self-tapping screw 4×1827 Cable clamping plate28 Switch 9565VCR29 Power cable 1, 0-2-2,530 Cable protection 831 Button 9565CVR ST115A-40||32 Protective cover33 Indicator label34 Motor housing cover35 Self-tapping screw 4×1836 Controller 9565CVR37 Change-over lever38 Compression spring439 Brush holder40 Motor housing 9565CVR41 Pull switch42 Carbon brushes CB- 31843 Brush holder44 Self-tapping screw PT3x1045 Identification label46 Flange nut and supernut47 Inner flange and supernut48 Flange guard 9565CVR49 Screw M5x1650 Spindle screw 9565CVR51 Labyrinth ring52 Screw m4x1653 Bearing plate 9565CVR54 Ball bearing 6201DDW55 Safety ring 19- 3356 Ring 5257 Pinion gear 9565CVR60 Self-tapping screw 4×2861 LabelHandle and Vibration-proof Handle Special 35Gearbox Lubricant|
Original Makita spare part. For: All Makita angle grinder models, etc. Dimensions: Outer diameter 50 mm/ Inner thread M14/ Height (dimension) 13.5 mm/ To minimize “sticking” of interchangeable accessories, hand fixation.
Original Makita part. For Makita 9564CV; 9565C; 9565CLR; 9565CR; 9565CV; 9565CVL; 9565CVR; 9566C; 9566CR; 9566CV; 9566CVR; SG1250 angle grinder models. Parameters: Motor power 1400 W/ Outer diameter 60 mm/ Inner diameter 36 mm/ Charging frame length 55 mm/ Outer diameter cut 47.5 mm/ Center distance between mounting holes 49 mm/ Overall stator length 91 mm/ Number of leads 4.
Original Makita part. For: Makita GA6021, GA6021C, 9558, 9557 angle grinder. Parameters: Distance between the centers of the nut holes. 35 mm / Overall length. 199 mm.
Makita original spare part. For models: Makita 9562; 9562C; 9562CH; 9562CV; 9562CR; 9562CVH; 9562CVR; 9564; 9564CV; 9564H; 9564HR; 9565; 9565C; 9565CLR; 9565CR; 9565CV; 9565CVL; 9565CVR; 9565CVR; 9565H; 9565P; 9565PCV; 9566C; 9566CR; 9566CVR; PW5000C; PW5000CH; SG1250; SG1251. Parameters: Front anchor bearing seat diameter. 28 mm/ Centers of fixing holes on plastic motor housing. 78 mm/ Fitting diameter for lower shaft needle bearing. 19 mm/ Center of shaft cover mounting holes. 63 mm/ Hole diameter for shaft-lock button. 6.2 mm.
Makita Original Spare Part. Thread right/ Thread diameter 6 mm/ Thread pitch mm/ Nut height 3,5 mm.
Original Makita spare part. For models: 4300BV, 4301BV, 6510LVR, 9562, 9562C, 9562CH, 9562CR, 9562CV, 9562CV, 9562CVR, 9564, 9564CV, 9564H, 9565, 9565C, 9565CR, 9565CV, 9565CVR, 9565H, 9566C, 9566CR, 9566CVR, 9566CVR, 9910, 9911, SG1250, UH301D, UH302D, UH303D, GA5040, GA5040C, GA6040. Parameters: Inner diameter 6 mm/ Outer diameter 10 mm/ Thickness 1 mm.
Makita original spare part. For: Makita 9562; 9562C; 9562CH; 9562CR; 9562CV; 9562CVH; 9562CVR; 9564; 9564CV; 9564H; 9565; 9565C; 9565CR; 9565CV; 9565CVR; 9565H; 9565PCV. Parameters: Height (dimension). 13 mm/ Inner diameter. 8 mm/ Seating. without key mm/ Number of teeth 11.
Original Makita part. For models: 9562; 9562C; 9562CH; 9562CR; 9562CV; 9562CVH; 9562CVR; 9564; 9564CV; 9564H; 9565; 9565C; 9565CR; 9565CV; 9565CVR; 9565H; 9565PCV. Large: Outer diameter (clearance). 52 mm/ Inner diameter. 11.9 mm/ Seat. without key. Small: Height (clearance). 13 mm/ Inner diameter. 8 mm/ Seating. without key mm. Number of teeth large/small. 38/11.
Makita original spare part. For Makita models 9565CLR; 9565CR; 9565CV; 9565CVL; 9565CVR; 9565H; 9565P; 9565PCV; 9566C; 9566CR; 9566CV; 9566CVR; GD0800C; GD0810C; SG1250; SG1251. Parameters: Diameter 11.5×15.5 mm/ Height 11 mm/ Number of turns 5 pcs.
Makita original spare part. For models: 2012, 2012, 2012, 2012, 2012, 3901, 4101R, 4101RH, 4105KB, 4105KB, 5103R, 5104S, 5143R, 5600RD, 5600RD, 6402, 6701B, 9005B, 910, 9207SPB, 9217SPC, 9218SB, 9227CB, 9401, 9401, 9402, 9402, 9403, 9404, 9504BH, 9554HN, 9554NB, 9555HN, 9555NB, 9557HN, 9557NB, 9558HN, 9558NB, 9558PB, 9562, 9562C, 9562CH, 9562CR, 9562CV, 9562CVH, 9562CVR, 9564, 9564CV, 9564H, 9565, 9565C, 9565CLR, 9565CR, 9565CV, 9565CVL, 9565CVR, 9565H, 9566C, 9566CR, 9566CV, 9566CVR, 9803, 9900B, 9900B, 9903, 9920, 9924DB, 9924DB, BDA340, BDA341, BGA450, BGA452, BGD800, BJR181, BJR182, BO6040, BSS610, DA3010, DA3010F, DA3011, DA3011F, EBH252U, EBH253U, EM2650UH, EM2651UH, GA5000, GD0600, GD0601, GD0800C, GD0800C, GD0800C, GD0810C, GD0810C, GD0810C, HK0500, HK1800, HK1810, HP2010N, HR4000C, HR4500C, HR5001C HR5001C, JR3020, JR3030, JR3030T, JR3050T, JR3060T, JR3070CT, LS1016, LS1016, LS1016L, LS1016L, LS1216, LS1216, LS1216L, LS1216L, LT2454, MS2454U, MS2454UE, MS2464U, MS2464UE, MT582, PC1100, PW5000C, PW5000CH, PW5000CH, SA7000C, SG1250, SP6000, UC120D, BHR261, HS7601. Parameters: Diameter inside 11 mm/ Thickness 1 mm.
Diagram of an alternating current collector motor
The diagram shows the electrical connections of the stator windings, rotor windings and graphite brushes. The graphite brushes in the motor are mounted in brush holders. Brushes are in contact with the collector lamellae. The other ends of the stator windings are connected to an external power source. The other ends of the stator windings are connected to the graphite brushes, the circuit is shorted to the rotor windings.
The angle grinder speed controller is wired to the collector motor circuit in series. The connection diagram of the speed regulator should be specified on the regulator body itself, or in the operating manual of the angle grinder.
Angle grinder construction
On the device of the angle grinder, everything is shown in the figure and any explanations are not required. Slave and drive bevel gears are used to transmit the rotation from electric motor to gearbox shaft.
Faults of the collector motor
Possible causes of angle grinder motor failure are as follows:
- wear of the rotor collector;
- wear of graphite brushes;
- burnout of stator winding;
- burnout of the rotor windings;
- lack of contact connection of stator winding ends with graphite brushes;
- mechanical damage of cable wire at the base of the plug;
- mechanical damage to the wire along the cable length;
- Condenser failure,
and other possible causes related to any disruption in the electrical circuitry.
Inspection of collector electric motor
The cause of collector motor failure is detected by a measuring instrument, with the example of such devices as:
If a gauge is not available, any gap can be identified with a screwdriver.
So let’s say stator winding burnout is usually caused by general overheating of the electric motor. In this case the insulation of the wires in the stator winding is broken and the winding itself can be shorted to the frame. To determine this possible cause of malfunction, one probe tip is connected to the lead end of the stator winding, the second probe tip is connected to the stator bed housing.
To check the rotor winding, the feeler probes should be connected to the lamellae (plates) of the collector
suggest, please, the cross section of the stator winding wire angle grinder Kolner 580 wt.Number of turns 167
Hello, gentlemen electricians! Please tell me why the angle grinder‘s motor is heating when rotating at idle for 2-3 minutes after turning on after replacing the rotor. Initially, when working with a diamond wheel on a new angle grinder overheated it by stopping the wheel at full rotation of the rotor. Disassembled, checked rotor. broken circuit on manifold (two blades black). Never tested any other items. A new rotor was installed and it is warm without any load.