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• WHY DOES MY EVERYDAY JIGSAW NOT WORKING FREE

Remove any hold down clamps, then lift the motor up and slide the armature assembly free of the field. To do so, remove the base as well as the screws securing the case of the jigsaw together and separate. If the jigsaw will not turn on, you can check the field for continuity. The field coil is an electromagnet, used to generate the magnetic field needed in an electro-magnetic machine. Reassemble the jigsaw case back together. Place down inside the case and reinstall any clamps. If an armature fails any of these tests, it is recommended that you replace it.Īttach the armature to the front gear assembly of the jigsaw and then slide the armature into the field. If the resistance drops, that would indicate there is a short. If there is an increase in resistance, that would indicate a broken or burnt wire. Once again, what is important is that there is not a large fluctuation in values, which would indicate a fault. There will be a specific set of readings for this, depending on the design of your unit. Attach the two ends of the ohmmeter on the commutator bars, directly across from each other. The third, and final, test is the 180-degree test. Move around the commutator, checking each bar. If the resistance drops, then there is a short. If there is an increase in resistance, this will indicate there is a broken, or burned out, wire in the coil. But, most importantly, there should not be a large fluctuation here between the values, which would indicate a fault. There will be a specific reading for this, depending on the design of the armature. Attach one probe to a bar on the commutator and the other probe on the bar right beside it. The second test is a bar-to-bar test, to determine the resistance. If the ohmmeter shows a reading on one of the bars, this will indicate a short and a bad armature. Move the probe to each bar on the commutator, checking all the bars. Attach one end of the ohmmeter to the shaft for ground and the other to the bar on the commutator. With the armature removed from the unit, stand it up on a bench. There are three tests to use when checking an armature. Inspect for any burn marks, or damage, that may indicate a problem. Clean the armature with electrical contact cleaner. On some models, the armature assembly will be attached to the gears and you will have to pull the armature free of it. Lift the motor assembly out of the case and slide the armature assembly free of the field. To check the armature for continuity, remove the base and take out the screws securing the case of the jigsaw together and separate. The armature is the power-producing unit of the motor, located inside the field of the motor.