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Need more start up torque

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randyjaco

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#1
I picked up a 20's model Heston and Anderson 14 " bandsaw for cheap. The problem is that it has very little start up torque. Once it is running it seems to have plenty of power. I would like to keep the original motor if possible. The motor in question is a 1/3 hp Century. I can’t locate the capacitor, so that idea seems to be out. I have loosened the belt and blade, so the saw turns very easily. Still about the half the time, I have to spin the wheels to get it started. All the electrical connections are clean and fresh. The motor pulley is about as small as possible. Any ideas on what I can do to get this puppy to start up on its own?

TIA
Randy
 

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whitmore

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#2
Are the bearings still relatively tight? There's a possibility that bearing wear has
allowed the rotor to go off-center, in which case there might be a 'dead' zone
that doesn't give you much starting torque. After the motor hits speed,
the oil film makes the rotor better-centered in the stator. That's an unvented
motor with oil cups; it has a LOT of age on it, you might want to consider
a newer replacement.
Can't tell from the pix, if it has 120/240 windings, it'll start and run
better from 240AC.
 

Rustrp

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#3
At first guess, the start windings, if there's no capacitor and as whitmore stated the bearings may be causing the motor to lock/stay in position due to worn bearings/bushings which were common. A close-up of the data plate might help or just post the data. There were many changes happening in electric motors during that era, and over a short period of time. Good luck on keeping it original.
 

Ulma Doctor

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#4
the motor may have worn bearings, i'd try there first.
if you measure the ID, OD and bearing width- you can get replacement bearings from EBay - cheap
i'd get ABEC3 bearings (minimum)- the ABEC# gets larger as the precision of the bearing is better.
they may be Inch measurements on the bearings due to age,
but if the measurements don't come out in inches- measure the bearing in Millimeters and you'll be able to ascertain the correct bearing.
you may be lucky and the bearing may have the size inscribed on the bearing shield or the bearing race itself

if you have a hard time finding what bearings you need, feel free to send me a PM- i'll help out :)
 

Uglydog

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#5
I hope you keep her OEM.
If you decide you need to change out the motor please note that those pre NEMA motors can be hard to find (not impossible- but they aren't made anymore).
There may be somebody who is desperate for one even if only a 1/3hp.

Daryl
MN
 

f350ca

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#6
Could it be a repulsive start / induction motor? Can you see a commutator through the removable end cover? It looks old enough that it could be. Might need brushes or the mechanism that engages/disengages them is sticking. If it is one they have incredible starting torque when working.

Greg
 

woodchucker

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#7
the motor may have worn bearings, i'd try there first.
if you measure the ID, OD and bearing width- you can get replacement bearings from EBay - cheap
i'd get ABEC3 bearings (minimum)- the ABEC# gets larger as the precision of the bearing is better.
they may be Inch measurements on the bearings due to age,
but if the measurements don't come out in inches- measure the bearing in Millimeters and you'll be able to ascertain the correct bearing.
you may be lucky and the bearing may have the size inscribed on the bearing shield or the bearing race itself

if you have a hard time finding what bearings you need, feel free to send me a PM- i'll help out :)
I doubt these are ball bearings if it has oil cups. My century motor has plain brass or bronze bearing, with felt oil pads .. I think they can easily be replaced with oilite bearings ..
 

markba633csi

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#8
If you can turn the motor by hand I would rule out bearing issues. Open up the motor and check the centrifugal switch, the contacts may be obliterated or the mechanism may be sticking. A shot of silicone spray might do the trick. Possibly the start winding may be open circuited or a wire may have fallen off. This motor looks like it doesn't use a starting capacitor so fairly simple to fix.
Mark S.
 

Keith Foor

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#9
I just looked at other 14 inch metal cutting band saws and they all had 3/4 or 1 HP motors.
Is the Century motor really the original motor or was it re-powered at some point by the previous owner and not done correctly?
I would check the date coding here and see if the age of the motor matches the date of manufacture of the saw.
http://vintagemachinery.org/mfgindex/detail.aspx?id=2461

Keeping things original is great when possible. But having working machinery is more important to me persoanlly than having a museum quality tool in my shop that I can't use. Your thoughts and mileage may vary.
 

Rustrp

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#10
If you can turn the motor by hand I would rule out bearing issues. Open up the motor and check the centrifugal switch, the contacts may be obliterated or the mechanism may be sticking. A shot of silicone spray might do the trick. Possibly the start winding may be open circuited or a wire may have fallen off. This motor looks like it doesn't use a starting capacitor so fairly simple to fix.
Mark S.
When the bearings are bad, in this case probably bronze bushings, they would probably be worn on the bottom or bottom left or right side of the bushing, and that would be determined by the rotation. The bushings have a wall thickness of 1/8" +/-. The worn bearing/bushing allows the rotor/armature and stator/field windings to be to close together, resulting in a humming, groan (I'm trying) sound that's solved by giving it a little help.

For troubleshooting purposes the bushings can be rotated so the worn section is towards the top, and the motor will usually start up.
 

randyjaco

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#11
I just looked at other 14 inch metal cutting band saws and they all had 3/4 or 1 HP motors.
Is the Century motor really the original motor or was it re-powered at some point by the previous owner and not done correctly?
I would check the date coding here and see if the age of the motor matches the date of manufacture of the saw.
http://vintagemachinery.org/mfgindex/detail.aspx?id=2461

Keeping things original is great when possible. But having working machinery is more important to me persoanlly than having a museum quality tool in my shop that I can't use. Your thoughts and mileage may vary.
Since it's likely to be a 1920's motor, the codes didn't work. I am going to have to tear it down next week. Too many things happening this week.
 
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