motor rebuilds

[Casey]

Hey guys, I have a sweep motor that doesn't want to work. It starts and when the sweep is on its way down to guard it stops. It's a national motor. I replaced it with a franklin. What all do I look for when I tear it apart? What parts should I replace? Etc. I have never rebuilt a motor. I have a rebuild manual but it doesn't trouble shoot anything. Is there somewhere I can read up on what causes certain behaviors in motors?

[Jimmy Jam]

Re: motor rebuilds

Hey Casey,

Looks like you found out what was causing that jerking sweep you had a few weeks ago. :p

[Casey]

Re: motor rebuilds

yep sure did, it happened to be a combination of a drifting motor and cam adjustment. Had me baffled for a while there. Now if I could just fix motors [img]/content/btubb/images/%%GRAEMLIN_URL%%/confused.gif[/img]

[craigchandler]

Re: motor rebuilds

does it stop, or does it overload?

[Casey]

Re: motor rebuilds

The motor comes down to guard but stops short of 1st guard. It does not overload just stops. Also tested in another machine, several weeks ago and the motor came down to guard slamming against the lane, then it would reverse (raise the sweep) 6 inches or so....then come back down hard again. It would just go up and down, until I killed the power.Tested again last week and it does what it currently is doing, stopping short of guard. I don't know a thing about motors. It would be nice if there is somewhere I could read up on how to trouble- shoot a motor.

[John_Galt]

Re: motor rebuilds

Well I'm certainly no motor expert but...
Perhaps the RUN winding is just shot.
There are two windings: The START winding and the RUN winding. the START winding is high-torque, low horsepower; the RUN winding is low-torque, high horsepower.
If your RUN winding is shot, you're getting low-horsepower and low-torque when it's supposed to run.

The only fix for this that I know is to order a new motor.
They don't sell replacement windings, do they?

"But I could be WAY wrong!"
Chad Q.

[GPS]

Re: motor rebuilds

Hey Casey, If your sweep is stopping BEFORE 66 degrees (guard position) turn SB cam lever screw IN a half a turn at a time until the sweep comes to a full guard position. Good Luck.

[Coors]

Re: motor rebuilds

Quote:]Originally posted by GPS:
turn SB cam lever screw IN a half a turn at a time until the sweep comes to a full guard position. [/QUOTE]
i was thinkin that too. . . .but casey says its in the motor. . .for U and i to be right GPS. . .ALL the cam adjustments in the house would have to be off (not unheard of with nationals) and this motor has one hell of a braking circuit. . .compared to the others in the same house. . .i hope we're right and thats all it is

[craigchandler]

Re: motor rebuilds

can't you guys in the states, get the motor rewound, to throw a motor in the bin is unheard of here, if your going to do that, throw it my way

i would be getting the motor rewound, and maybe checking for a faulty motor plug, or maybe a short in the wireway

[Casey]

Re: motor rebuilds

yeah this problem is most certainly in the motor. What do I need to replace in a typical rebuild? Just carbon brushes and start switch? I was kinda forced into taking the previous mechanics job. He wasn't a motor person either. But at least I'm willing to learn.

[felix]

Re: motor rebuilds

Dear Craig Letter: I think everyone can get A motor rewound in the states, but what everyone or most need is the box for the work bench to turn em on and off. combo motors that is,or the repair shop cannot run to check and recheck.

[Jimmy Jam]

Re: motor rebuilds

If you've narrowed it down to the stator check its wiring compared to a good stator. Maybe you will stumble accross the problem.

[Justy]

Re: motor rebuilds

Have come across a similar problem though a junior tech had wired up the motor switch incorrectly. Also wires were catching the cent-mech and sparking nicely sending the sweep all over the place for a time.
Maybe of some help to you.
(personally, i blame the chief for insufficient training ..... oops!)

[Tod hiles]

Re: motor rebuilds

I had a sweep doing the same thing with a national moter, it was the gear box the outer bearing coller split in half and the drive shaft would move around some and change the cam swiches so the sweep would not stop in the same place twice and some times would not stop at first gard. Had to pull gear box apart to find it.
hope this helps

[Guest]

Re: motor rebuilds

Casey,

Providing the windings are good, (You can use an ohm meter to check for resistance and continuity), I would convert the centrifugal mechanism to AMF's solid-state start switch.

General rebuild to a national motor is changing the brushes, inspecting the brush springs for over compression. Have the brake disc turned. New bearings. Inspect the bearing housings end pieces for excessive slop. A new spring washer and your back in business.

Oh ya, a good blow out before the above procedures is also recommended.

Tech