While using my trusty Delta bandsaw (14 years old) there was a bang and it slowed down to about half speed. I can turn it off and turn it on but it runs slowly. It has a 3/4 HP, 120 volt motor.
I checked the drive train and the mechanical parts but found all in good order.
I am informed that if the starting capacitor was shot the motor would not start.
Is it possible for a motor to partially burn out? Or is something else going on?
If it is the motor can it be repaired or is replacement a better bet. Can a larger motor (say 1 hp) be used and what is a good source.
Would appreciate any input.
Replies
Single phase motors must have a separate set of magnetic coils in them to get the motor started. A failed condenser or a failed centrifugal switch inside the motor housing will cause problems with engaging the starting coils and create the symptoms you are describing. Running the motor in this condition will quickly cause it to severely overheat.
If your motor has two separate condensers on the outside of the housing, the second condenser is connected to the run windings to make the motor run more efficiently. If the run condenser fails it may also cause the symptoms you describe.
Condensers, when they fail can explode, so your comment about hearing a bang would suggest that a condenser bit the dust. If you open up the plastic or metal cover over the condenser it will probably be obvious that it has failed. Older condensers used to contain PCBs that are toxic but your motor is new enough that any oil leaking out of the condenser isn't likely to be truly dangerous, but I would avoid skin contact with it none the less.
You can replace the part yourself, or a motor repair shop can do the work, probably for somewhat less than the cost of a new motor.
If your saw doesn't have a riser block, a 3/4 horsepower motor is plenty of power. If you resaw wide stock with a riser block you might want to install a 1 horse motor for a replacement, but with a sharp blade, 3/4 horsepower is still adequate.
The original motor on your saw was probably an open frame where air is blown directly through the motor to cool it off. With this set up dust accumulates in the motor causing overheating and centrifugal switch problems. If you buy a new motor, it is worth spending a bit more to get a totally enclosed fan cooled (TEFC) motor.
John White
This forum post is now archived. Commenting has been disabled