My belt broke today, and when I opened the hood it was twisted up good and bent the alternator bracket a little, no big deal with that it can be straightend. but I have never delt with an alternator like this, as far as I know it's the original one, and it was still charging when belt broke, So I'm trying to figure out if the alternator caused this. It still spins but has resistance when turning the pulley, is this the magnetic action I am feeling or should it spin completely free of resistance. Just don't want to drop money into a new one if I don't need to.
B2150 alternator
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85Hokie
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Should have a little resistance - It should spin, but not freely.
Check alignment when you get a new belt on
Drop money on the belt, hook it up - check alignment and check the alternator with a volt meter.
On a 20+ year old machine, there's no harm in doing a bit of maintenance if you have the time and inclination, pull the alternator, replace the bearings and check the brushes, it should spin fairly freely excepting the drag of the brushes which isn't great, but will stop it from free running..............YMMV
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As I was reading your post on the B2150 alternator, I had an idea I will share with you.
I don't know this model but is it possible this a dynamo with permanent magnets to create the field rather than a winding, and the resistance being felt is just the interaction between the permanent magnets and the stator metal core?
Messick's shows a dynamo and an optional alternator.
If your "alternator does not look like the one in this post then as 100 td suggested checking bearings would be a good idea. In the dynamo, Messicks does not show any replaceable parts but that may not be the final word.
Dave M7040
I don't know this model but is it possible this a dynamo with permanent magnets to create the field rather than a winding, and the resistance being felt is just the interaction between the permanent magnets and the stator metal core?
Messick's shows a dynamo and an optional alternator.
If your "alternator does not look like the one in this post then as 100 td suggested checking bearings would be a good idea. In the dynamo, Messicks does not show any replaceable parts but that may not be the final word.
Dave M7040
85Hokie
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"I don't know this model but is it possible this a dynamo with permanent magnets to create the field rather than a winding, and the resistance being felt is just the interaction between the permanent magnets and the stator metal core"
this is true! The magnetic field FROM the magnets, and the windings of the coil WILL have a frictional impact while spinning. Almost a rump-rump.
Bearings are easily found and replaceable. Bet cha the bearing is a 6201.
It is very rare that the windings are bad, and unless magnets have come loose - it is dead simple to repair.
this is true! The magnetic field FROM the magnets, and the windings of the coil WILL have a frictional impact while spinning. Almost a rump-rump.
Bearings are easily found and replaceable. Bet cha the bearing is a 6201.
It is very rare that the windings are bad, and unless magnets have come loose - it is dead simple to repair.
You guys are correct, it is the dynamo like the one pictured above, like I said I'm not familiar with this type so I don't know what's normal, it's kind of hard to explain the resistance while spinning but it's kind of like a cam lobe effect, I did pull it apart and bearing looked good along with the winding, but it was really dirty, and caked with fine powder, So I just cleaned real good with electrical contact cleaner. I picked up a new belt, going to install tonight and see how it goes.
85Hokie
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WHEN you get the belt on and BEFORE you hook the two blue (from picture used) small wires back up, and those really do not matter which goes to which - test it with the tractor running.
Set your multimeter to AC - and place the leads on the two blue wires, you should have a reading from 20 - 35 volts AC - depending on the RPM of your tractor.
If you get a good AC reading - cut off tractor, hook up wires back to regulator.
Check battery voltage on DC with tractor off - should be 12.5 ish or higher.
Start tractor - rev up a bit, and now check battery again, should be 13+ volts.
Report back your findings.
Ok, dynamo, not alternator, no brushes, still 20+ years, still worth changing bearings while you have the opportunity. If you search you will find instances of thrown belts, shredded belts etc., due to bearings. YMMV
Got dynamo back on and seems to be running smooth.
Checked ac reading meter set on vac it read 14.7
At battery tractor off, reading 12.7 D.C.
With tractor running, reading 13.6 D.C
85Hokie
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BX-25D ,PTB. Under Armor, '90&'92-B7100HST's, '06 BX1850 FEL