Demolition Hammer: Excessive Sparks From the Motor
If you notice excessive sparks coming from your motor, you should check these parts: carbon brush, armature, cap, and field. Our expert technicians will then walk you through how to check and replace the part in question. Refer to your owner's manual for advice on your specific model.
Remove the screws securing the housing from the motor and take it out of the unit. Pull the armature out of the housing and remove it from the bearing housing. You can do this by placing it in a vice and use a spanner wrench to spin the cap back on. You also can place a punch in the side of the notch and tap it with a hammer to spin it loose. Remove the nut underneath the cap. Check the commutator for burn marks. At this time, you can clean the...
Remove the screws securing the housing from the motor and take it out of the unit. Pull the armature out of the housing and remove it from the bearing housing. You can do this by placing it in a vice and use a spanner wrench to spin the cap back on. You also can place a punch in the side of the notch and tap it with a hammer to spin it loose. Remove the nut underneath the cap. Check the commutator for burn marks. At this time, you can clean the commutator with a file or sandpaper to get rid of the burn marks – this is usually the cause to sparks.
To check for a bad armature, you can perform the 180-degree test. With the armature removed from the unit, stand it up on a bench. With an ohmmeter, attach the two ends to both sides of the commutator to measure the resistance of the windings. As you move it around the commutator, the reading number is not important. You are looking for a consistent reading, indicating all the windings are good. If it varies, radically reading zero, or open circuit, then the armature is bad. Another test is reading. If the ohm reads zero, or open circuit, then that indicates a bad armature. The last test is a bar to ground test, which is done by placing one end of the ohmmeter to the tip of the shaft of the armature and the other end to the commutator. If the armature is bad, install a new one.
Reinstall the fan and the brush holder back in the bearing housing, ensuring the tabs line up on the brush holder. Place the armature in the housing and reinstall the nut. Place in a vice to tighten. Spin the cap back on and tighten. Slide the armature back in the housing (the same way you removed it) then reattach the housing assembly back on the unit. Secure the screws tight. Reattach the handle.
To check this part for excessive sparks, and to clean or replace it, remove the screws securing the motor housing to the demolition hammer. Now, remove the armature from the motor housing. Clear off any clamps, brackets, and screws holding the field in place inside the motor housing. Disconnect all wires going to the field. Pull the field out and inspect for burn marks.
Any burn marks on the field indicates it is sparking and requires replacement. If the field looks fine, clean it thoroughly in thinner and dry completely before reinstalling. Install the new field, or cleaned field, in the...
To check this part for excessive sparks, and to clean or replace it, remove the screws securing the motor housing to the demolition hammer. Now, remove the armature from the motor housing. Clear off any clamps, brackets, and screws holding the field in place inside the motor housing. Disconnect all wires going to the field. Pull the field out and inspect for burn marks.
Any burn marks on the field indicates it is sparking and requires replacement. If the field looks fine, clean it thoroughly in thinner and dry completely before reinstalling. Install the new field, or cleaned field, in the housing and fasten it back down. Reattach all wires and slide the armature back in place. Reattach the motor housing back on the demolition hammer.