May 2015
I have a drill press that has a five amp fuse that recently has started to blow on just about every project. I am not working on harder material and the bits are sharp, so I don't think its increased torque from friction which leaves the electronics. As this is simply a motor and a power switch, I can’t imagine what might be causing the increased current draw. Suggestions?
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One thing that was not mentioned was a start run capacitor. Does the motor have a "hump" on it? If it does, there is a capacitor under it and it is probably bad. You can check it with an ohm meter when it is disconnected. See if the capacitor has not charged and causes the ohm meter to give some funny reading, like a negative reading. If it is shorted or open it is defective.
Mr. Olivo is experiencing nuisance fuse blowing in his drill press. The problem may well be that the fuses that he has been using cannot tolerate the inrush current demand of the motor. At the instant of power application, the magnetic state of the motor core may be such that the first half-cycle of utility power drives it into saturation.
Assuming that the fuse is a 1/4” x 1-1/4” cartridge fuse, a Bussmann MDL-5 fuse will open at five amperes, but will tolerate more than one hundred amperes during a one-half cycle of utility power. See the time-current curves for this family on data sheet #2004, which is downloadable from web page www.cooperindustries.com/content/public/en/bussmann/electrical/products/electronic_smalldimension/elx_1_4_x_1-1_4_/mdl-v_mdl.catalog_numbers_(amps).brands.cooper_bussmann.html
If the fuse is another size, check with your local electrical jobber for an appropriate fuse having similar inrush tolerance. Good luck.
Does the dill press sound any different? Maybe the bearing in the motor is wearing out causing the increased load.
What about the cord? Has it been pinched/damaged in any way? Or even the outlet that it is plugged into, are there visible signs of scorching?
Lastly, how old is it? Could the motor be electrically failing? Things to consider beyond stresses due to operator use.
If this is just an on/off, switched drill press, then you definitely have an excessive friction issue. If a good lubrication doesn’t help, then the brushes or commutator in the motor are worn and binding.
Worn bearings could be allowing the armature to rub on the stator. Remove the belt and try to move the motor shaft; if it moves at all, it is bad.
:You don't say what type of fuse you are using but if it is a buss type glass fuse, you might want to make sure you are using a slow-blow type fuse for your drill press.
