Please Help - Need Motor or fields for 8635 Clausing Power Feed

[Jim the PA Hunter]

Hi,
Newbie here.... I have a Clausing 8520 Vertical Knee Mill with a 8635 power feed. Just got everyting setup and running and found that the 8635 power feed runs good and fast in one direction but not the other(runs very slow). The manual has the schematic for the power feed. I looked it over and decided it must be a control problem so I replaced the 10 c powerstat AND the dbl throw, dbl pole, center off switch. I wired it as the schematic showed which was the same way it had been wired so, no mistakes there. I verified all with the Clausing Co. also. Still same problem, slow one direction and fast the other. This is tested while the unit is off the machine so no binding possible. Wired motor direct to AC and checked in both directions, same problem. New brushes, rewired armature at electical shop and still the same problem???? Only thing left is the fields??? I'm looking for a new motor or one that is missing or has a bad armature. Its 120vac gear motor. The 8635 manual lists the motor as part number 486-009. One other thing I noticed is, there is a 8 inch long stranded wire listed in the parts manual which is part number 942-003. It appears to be connected to the switch. Unless it is the harness from the motor with the red,black,yellow, and brown wires in it I do not know what it is for. Anyone know? I'd really like any help I can get here!
Thanks for your time.
Jim

[MaxHeadRoom]

Some thing sounds odd, if the motor has brushes and wound fields and you can run on AC then it would appear to be a Universal motor.
The strange part is that the same fields are in series with the armature in both directions and the reversing is done by either reversing the field or the armature with respect to each other.
Being series the current is the same for the field and the armature
What is the total resistance through the fields in both polarities of the meter?
Is there a schematic of the drive and hook up?
Max.

[Jim the PA Hunter]

Hi Max,

Thanks for the post..... here is a fella that has the 8635 schematics:
http://igor.chudov.com/manuals/Claus...eed-Manual.pdf

You apparently know more about electrical motors than I do!

I will use my fluke and see if I can measure the current flow to the fields and the total resistance through the fields. I will see if I can fiqure it out. If the fields are working in one direction, why would they not work in the other? I noticed there is alot of black soot on the fields. Would that hinder them?
Thanks,
Jim

[MaxHeadRoom]

Just by looking at the diagram it seems there is just a high wattage pot and a reversing switch.
The fact that AC flows through the armature and fields, I don't quite see what other omni-directional component would be in the there in the reverse?
I take it you tried it directly off of AC?
By-passing the pot and switch, this way you can reverse the fields manually and ensure there is nothing else in circuit.
Max.

[Don Young]

Your problem is almost certainly somewhere in the switching arrangement, either the switch itself or the connections. I can think of no problem with the fields (or armature for that matter) that could cause your problem (see edit below). It seems that one of the fields is being either opened, shorted, or reversed in relation to the other when being switched. The brushes and both fields should be in one series path regardless of direction. The fields as a pair should be reversed in respect to the brushes when the direction is changed.

Edit: Looking at your wiring diagram, there does not seem to be any way the external parts can cause your problem unless the switch had a high resistance connection, which you seem to have disproved. Therefore I suspect there is an internal wiring problem. Verify that the red and black wires both go to brushes and the yellow and black wires both go to fields, or vice versa. Verify that the ends of the fields not connected to the external wires are connected to each other, and to nothing else. Verify that there are no other connections or shorts between the wires. Also verify that none of the motor wires shows any continuity to the motor frame. There is a possibility that a partially grounded field coil could cause your problem.

[Jim the PA Hunter]

Don and Max,

I will be able to work on the power feed this weekend. I will let you know what I find. Thanks a million for your Help!

I went over that schematic several times. The switch actualy has a crisscross of insulated wires connecting the outer poles on both ends of the switch. The RED wire goes in the center of one side and the jumper to the 10c powerstat is on the other center terminal. The yellow wire is on the lower left terminal on the switch and the brown wire is on the lower right terminal of the switch. The yellow and brown wires are for each direction. I will see what I can find out and let you know over the weekend.
Thanks again...... this has been a real experience!
Jim

[Jim the PA Hunter]

[I take it you tried it directly off of AC?
By-passing the pot and switch, this way you can reverse the fields manually and ensure there is nothing else in circuit.
Max.[/QUOTE]

YES Max I did and still the motor runs fast in one direction and slow in the other ... go figure !

Jim

[J. R. Williams]

If the motor runs OK in one direction and slow in the other direction the problem is probably in the reversing switch.

[Jim the PA Hunter]

If the motor runs OK in one direction and slow in the other direction the problem is probably in the reversing switch.

J. R., NEW SWITCH..... I verified the switch was good and wired it EXACTLY as the old one and verified with the wiring diagram (see link mentioned in this thread). Again, no switch, no powerstat, wired motor direct to AC and switched direction using the direction wires yellow and brown and still same problem. Runs fast in one direction and slow in the other. Something's goofy in the fields I think.

BTW: The armature was rewound due to this problem but it still does the same thing.

Jim

[J. R. Williams]

One thing that is wrong is the original wiring diagram has the line fuse in the white power lead wire. If the switch is correct with the two outer terminals crossed then the field connection will be reversed as required. The next place to check is the brush holders and brush 'pig tail' wires. Changing rotation direction forces the brush to opposite side in the holder. I have seen broken wires to the brushes or a bad solder joint with the top end of the pig tail wire to a small brass washer.