Laminate Trimmer: Excessive Sparks Coming From the Motor
Excessive sparks coming from the motor of your laminate trimmer can seem concerning, but it is actually something you can fix yourself. First, check out the parts we have listed below as being the most commonly related to this problem. Once you have the part narrowed down, use our repair guide to get your tool back to working effectively on your own.
Armatures
The armature is located inside the field of the motor and is the power-producing unit. An armature going bad will produce excessive sparking. The following repair procedures will vary on all models, but the repair will be similar. To check the armature, remove the base and the motor housing. Remove the tension springs on the carbon brushes and pull the brushes out. On some models, this is done by removing the brush caps on the side of the unit. Make a reference mark on the upper and lower motor housing for reassembly.
Separate the upper and lower half of the motor housing by removing the screws and then tapping it free with a rubber mallet. Remove the collet from the shaft. Using a rag, or a glove, tightly hold on to the end of the armature shaft as you use an impact wrench to remove the chuck. Use a rubber...
Separate the upper and lower half of the motor housing by removing the screws and then tapping it free with a rubber mallet. Remove the collet from the shaft. Using a rag, or a glove, tightly hold on to the end of the armature shaft as you use an impact wrench to remove the chuck. Use a rubber...
The armature is located inside the field of the motor and is the power-producing unit. An armature going bad will produce excessive sparking. The following repair procedures will vary on all models, but the repair will be similar. To check the armature, remove the base and the motor housing. Remove the tension springs on the carbon brushes and pull the brushes out. On some models, this is done by removing the brush caps on the side of the unit. Make a reference mark on the upper and lower motor housing for reassembly.
Separate the upper and lower half of the motor housing by removing the screws and then tapping it free with a rubber mallet. Remove the collet from the shaft. Using a rag, or a glove, tightly hold on to the end of the armature shaft as you use an impact wrench to remove the chuck. Use a rubber mallet and tap the armature free from the housing. Clean the armature with electrical contact cleaner and inspect the armature for burn marks, indicating excessive sparking.
To verify if an armature is good, or has gone bad, there are three test to use when checking an armature. The first is a continuity test. With the armature removed from the unit, stand it up on a bench. Attach one end of the ohmmeter to the shaft, for ground, and the other to the bar on the commutator. Move the probe to each bar on the commutator, checking all the bars. If the ohmmeter shows a reading on one of the bars, this will indicate a short, meaning a bad armature.
The second test is a bar-to-bar test, determining the resistance. Attach one probe to a bar on the commutator and the other probe on the bar right beside it. There will be a specific reading for this, depending on the design of the armature. But, most importantly, there is not a large fluctuation here between the values, indicating a fault. If there is an increase in resistance, this will indicate there is a broken, or burned out, wire in the coil. If the resistance drops, then there is a short. Move around the commutator, checking each bar.
The final test is the 180-degree test. Attach the two ends of the ohmmeter on the commutator bars, directly across from each other. There will be a specific set of readings for this, depending on the design of your unit. Again, what is most important is that there is not a large fluctuation in values, indicating a fault. If there is an increase in resistance, that would indicate a broken or burnt out wire. If the resistance drops, that would indicate that there is a short. Continue this test on all the bars. If an armature fails any of these tests, it is recommended that you replace it.
Install the armature into the housing. You may need to tap it in with a rubber mallet. Reinstall the chuck with an impact wrench. Reinstall the collet and rejoin the two halves of the motor housing, lining up the reference marks. Reinstall the brushes and reapply the tension on the brushes. Reattach the motor cover and then the base.
Separate the upper and lower half of the motor housing by removing the screws and then tapping it free with a rubber mallet. Remove the collet from the shaft. Using a rag, or a glove, tightly hold on to the end of the armature shaft as you use an impact wrench to remove the chuck. Use a rubber mallet and tap the armature free from the housing. Clean the armature with electrical contact cleaner and inspect the armature for burn marks, indicating excessive sparking.
To verify if an armature is good, or has gone bad, there are three test to use when checking an armature. The first is a continuity test. With the armature removed from the unit, stand it up on a bench. Attach one end of the ohmmeter to the shaft, for ground, and the other to the bar on the commutator. Move the probe to each bar on the commutator, checking all the bars. If the ohmmeter shows a reading on one of the bars, this will indicate a short, meaning a bad armature.
The second test is a bar-to-bar test, determining the resistance. Attach one probe to a bar on the commutator and the other probe on the bar right beside it. There will be a specific reading for this, depending on the design of the armature. But, most importantly, there is not a large fluctuation here between the values, indicating a fault. If there is an increase in resistance, this will indicate there is a broken, or burned out, wire in the coil. If the resistance drops, then there is a short. Move around the commutator, checking each bar.
The final test is the 180-degree test. Attach the two ends of the ohmmeter on the commutator bars, directly across from each other. There will be a specific set of readings for this, depending on the design of your unit. Again, what is most important is that there is not a large fluctuation in values, indicating a fault. If there is an increase in resistance, that would indicate a broken or burnt out wire. If the resistance drops, that would indicate that there is a short. Continue this test on all the bars. If an armature fails any of these tests, it is recommended that you replace it.
Install the armature into the housing. You may need to tap it in with a rubber mallet. Reinstall the chuck with an impact wrench. Reinstall the collet and rejoin the two halves of the motor housing, lining up the reference marks. Reinstall the brushes and reapply the tension on the brushes. Reattach the motor cover and then the base.
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Bearings
A seized bearing will put a heavy load on the motor, causing excessive sparking as the motor struggles to rotate. Once you have accessed the bearings, spin to check them. If they are completely seized, replace them. If they spin really rough, and feel tight, that also indicates they need to be replaced. Good bearings spin freely, with no noise.
To check the condition of your bearings, remove the base and the motor cover. Release the tension on the brushes by pulling the tension spring to the side and then remove the brushes. Some models have caps on the side for easy removal of the brushes. Make a reference mark on the upper and lower housing for reassembly. Separate the upper and lower half of the motor housing by removing the screws, then tap free with a rubber mallet. Remove the collet from the shaft. Using a rag, or a...
To check the condition of your bearings, remove the base and the motor cover. Release the tension on the brushes by pulling the tension spring to the side and then remove the brushes. Some models have caps on the side for easy removal of the brushes. Make a reference mark on the upper and lower housing for reassembly. Separate the upper and lower half of the motor housing by removing the screws, then tap free with a rubber mallet. Remove the collet from the shaft. Using a rag, or a...
A seized bearing will put a heavy load on the motor, causing excessive sparking as the motor struggles to rotate. Once you have accessed the bearings, spin to check them. If they are completely seized, replace them. If they spin really rough, and feel tight, that also indicates they need to be replaced. Good bearings spin freely, with no noise.
To check the condition of your bearings, remove the base and the motor cover. Release the tension on the brushes by pulling the tension spring to the side and then remove the brushes. Some models have caps on the side for easy removal of the brushes. Make a reference mark on the upper and lower housing for reassembly. Separate the upper and lower half of the motor housing by removing the screws, then tap free with a rubber mallet. Remove the collet from the shaft. Using a rag, or a glove, tightly hold on to the end of the armature and use an impact wrench to spin the chuck free. Use a rubber mallet to tap the armature free from the housing.
Some units will have a bearing mounted in the housing as opposed to on the armature shaft. Using retaining ring pliers, remove the retaining ring that holds the bearing in place in the housing. Next, use a socket that only makes contact with the outer race of the bearing and tap it free from the housing. Bearings should spin free, with no noise. Turn the housing over and insert the new bearing. Use a socket that only makes contact with the outer race of the bearing to avoid any damage during installation. Tap the bearing in place.
Reinstall the retaining ring and then the armature into the housing by tapping it in place with a rubber mallet. To replace the bottom bearing, you can leave the armature inside the housing. Use a bearing puller to remove the bearing. Apply a small amount of grease to the shaft and install the bearing on the shaft. Place a socket on the bearings inner race to avoid damage to the bearing. Tap the bearing in place with a rubber mallet and reinstall the chuck with the impact wrench, followed by the collet. Line up the reference mark on the two halves of the motor housing and secure. Reinstall the brushes and reapply the tension on the brushes. Reattach the motor cover and the base.
To check the condition of your bearings, remove the base and the motor cover. Release the tension on the brushes by pulling the tension spring to the side and then remove the brushes. Some models have caps on the side for easy removal of the brushes. Make a reference mark on the upper and lower housing for reassembly. Separate the upper and lower half of the motor housing by removing the screws, then tap free with a rubber mallet. Remove the collet from the shaft. Using a rag, or a glove, tightly hold on to the end of the armature and use an impact wrench to spin the chuck free. Use a rubber mallet to tap the armature free from the housing.
Some units will have a bearing mounted in the housing as opposed to on the armature shaft. Using retaining ring pliers, remove the retaining ring that holds the bearing in place in the housing. Next, use a socket that only makes contact with the outer race of the bearing and tap it free from the housing. Bearings should spin free, with no noise. Turn the housing over and insert the new bearing. Use a socket that only makes contact with the outer race of the bearing to avoid any damage during installation. Tap the bearing in place.
Reinstall the retaining ring and then the armature into the housing by tapping it in place with a rubber mallet. To replace the bottom bearing, you can leave the armature inside the housing. Use a bearing puller to remove the bearing. Apply a small amount of grease to the shaft and install the bearing on the shaft. Place a socket on the bearings inner race to avoid damage to the bearing. Tap the bearing in place with a rubber mallet and reinstall the chuck with the impact wrench, followed by the collet. Line up the reference mark on the two halves of the motor housing and secure. Reinstall the brushes and reapply the tension on the brushes. Reattach the motor cover and the base.
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Carbon Brushes
The carbon brushes ride on the commutator, supplying electricity to the armature. When the carbon brushes wear out, they will produce excessive sparks. To check the condition of the carbon brushes, remove the motor cap and the brushes. Brushes measuring 1/8 of an inch, or less, are worn out and will need to be replaced. At this time, it is also a good idea to clean the commutator of dirt and debris as well. Make a reference mark on the housing and separate the two halves of the housing. Clean the commutator with a 600-grit aluminum oxide sandpaper by rotating the armature in the rotational-direction, to provide a smooth even surface. Use a plastic scribe to clean it between the bars on the commutator. Rejoin the two halves of the laminate trimmer back together and install the new brushes. Reinstall the motor cap. Some models will have brush caps on...
The carbon brushes ride on the commutator, supplying electricity to the armature. When the carbon brushes wear out, they will produce excessive sparks. To check the condition of the carbon brushes, remove the motor cap and the brushes. Brushes measuring 1/8 of an inch, or less, are worn out and will need to be replaced. At this time, it is also a good idea to clean the commutator of dirt and debris as well. Make a reference mark on the housing and separate the two halves of the housing. Clean the commutator with a 600-grit aluminum oxide sandpaper by rotating the armature in the rotational-direction, to provide a smooth even surface. Use a plastic scribe to clean it between the bars on the commutator. Rejoin the two halves of the laminate trimmer back together and install the new brushes. Reinstall the motor cap. Some models will have brush caps on the side for easy access to the brushes. Remove these with a screwdriver to check and replace brushes and reinstall the cap.
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Fields
The field works with the armature to create an electromagnetic field for the armature to spin. If the field is bad, it will spark excessively. Repair procedures will vary on models, as they are different, yet the repair will be similar.
To check a field, and replace it, remove the base and the motor cover off of the unit. Remove the speed control switch. Release the tension on the carbon brushes and then remove the upper bearing holder. Place a wrench on the lower shaft to keep it still and use an allen key to remove the screw in the upper armature shaft. Loosen the shaft by running the allen key.
Make a reference mark on the two housing for reassembly. Separate the two halves of the motor housing – you may have to tap loose with a rubber mallet. Disconnect the field wires at the switch and speed control,...
To check a field, and replace it, remove the base and the motor cover off of the unit. Remove the speed control switch. Release the tension on the carbon brushes and then remove the upper bearing holder. Place a wrench on the lower shaft to keep it still and use an allen key to remove the screw in the upper armature shaft. Loosen the shaft by running the allen key.
Make a reference mark on the two housing for reassembly. Separate the two halves of the motor housing – you may have to tap loose with a rubber mallet. Disconnect the field wires at the switch and speed control,...
The field works with the armature to create an electromagnetic field for the armature to spin. If the field is bad, it will spark excessively. Repair procedures will vary on models, as they are different, yet the repair will be similar.
To check a field, and replace it, remove the base and the motor cover off of the unit. Remove the speed control switch. Release the tension on the carbon brushes and then remove the upper bearing holder. Place a wrench on the lower shaft to keep it still and use an allen key to remove the screw in the upper armature shaft. Loosen the shaft by running the allen key.
Make a reference mark on the two housing for reassembly. Separate the two halves of the motor housing – you may have to tap loose with a rubber mallet. Disconnect the field wires at the switch and speed control, making note of where they attach too. It is a good idea to take a picture for reference.
Remove the brush holders from the motor housing and disconnect the field wire from the brush holder. Cut the other two wires from the field, as close to the crimped nut as possible to prevent loosing wire length. Remove the screws securing the field to the housing and remove the field. Clean the field with electrical contact cleaner and inspect the field for burn marks, indicating excessive sparking.
Using a multimeter, you can check the field for continuity. Set the multimeter to an ohmmeter and place a lead on each end of the coil in the field. If the reading is infinity for one, or more, of the coils, then the field is bad and requires replacement. If there is a major variance between the coils, then the field needs to be replaced.
Install the new field, making sure the wires are lined up. Secure the field into the housing with the screws. Strip back 1/4 inch of insulation on the wires that you cut coming from the field before. Re-crimp the wires back together, using a crimping nut. Connect the field wires to the brush holders. Reinstall the brush holders back in the housing with the insulators. Insert the speed control back in the housing and then the switch back. Make sure the wires are tucked into their appropriate channels. Rejoin the two halves of the motor housing, lining up the reference marks. Reinstall the upper bearing holder and secure. Tighten the set screws in the armature shaft with the wrench and allen key. Reattach the brush springs and then the speed control switch. Finally, reattach the motor cover.
To check a field, and replace it, remove the base and the motor cover off of the unit. Remove the speed control switch. Release the tension on the carbon brushes and then remove the upper bearing holder. Place a wrench on the lower shaft to keep it still and use an allen key to remove the screw in the upper armature shaft. Loosen the shaft by running the allen key.
Make a reference mark on the two housing for reassembly. Separate the two halves of the motor housing – you may have to tap loose with a rubber mallet. Disconnect the field wires at the switch and speed control, making note of where they attach too. It is a good idea to take a picture for reference.
Remove the brush holders from the motor housing and disconnect the field wire from the brush holder. Cut the other two wires from the field, as close to the crimped nut as possible to prevent loosing wire length. Remove the screws securing the field to the housing and remove the field. Clean the field with electrical contact cleaner and inspect the field for burn marks, indicating excessive sparking.
Using a multimeter, you can check the field for continuity. Set the multimeter to an ohmmeter and place a lead on each end of the coil in the field. If the reading is infinity for one, or more, of the coils, then the field is bad and requires replacement. If there is a major variance between the coils, then the field needs to be replaced.
Install the new field, making sure the wires are lined up. Secure the field into the housing with the screws. Strip back 1/4 inch of insulation on the wires that you cut coming from the field before. Re-crimp the wires back together, using a crimping nut. Connect the field wires to the brush holders. Reinstall the brush holders back in the housing with the insulators. Insert the speed control back in the housing and then the switch back. Make sure the wires are tucked into their appropriate channels. Rejoin the two halves of the motor housing, lining up the reference marks. Reinstall the upper bearing holder and secure. Tighten the set screws in the armature shaft with the wrench and allen key. Reattach the brush springs and then the speed control switch. Finally, reattach the motor cover.
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Switches
The switch controls the flow of electricity to the motor. Over time, the switch can wear out and in some cases, cause sparking. To check the condition of the switch, begin by removing the motor cover and any brackets holding the switch down. Disconnect all electrical terminals at the switch. Inspect the switch for melting and burn marks, indicating sparking and overheating. If there are signs, replace the switch. Connect the wire terminal to the new switch and secure the switch in any hold-down brackets. Finally, reattach the motor cover.
The switch controls the flow of electricity to the motor. Over time, the switch can wear out and in some cases, cause sparking. To check the condition of the switch, begin by removing the motor cover and any brackets holding the switch down. Disconnect all electrical terminals at the switch. Inspect the switch for melting and burn marks, indicating sparking and overheating. If there are signs, replace the switch. Connect the wire terminal to the new switch and secure the switch in any hold-down brackets. Finally, reattach the motor cover.
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