221 motor help

To get the motor to run with the e-unit out of thr circuit you need to put power to one brush, connect the other brush to the field lead and the other field lead needs to be grounded.  Put the other power lead to ground.  It should run.  If not first thing I would look for would be a mechanical problem.  Worn bearings could be letting the armature hit the stator or brush plate.  If it is not mechanical, I would check to see the neither the field or armature windings are grounded somewhere they should not be.  Check the commutator to the motor shaft.  Lift the field lead from ground and check the field to ground. 

In order to conduct David Johnston's test you will need to disconnect the reversing unit.

There should be somewhere around 1 ohm of resistance between any two segments of the commutator (armature). There should not be any conductivity between any commuator segment and the armature shaft.

Do not apply power directly to the brushes. As David J. wrote, the field winding should be wired in series with the armature. Typically one field wire is attached to the motor's frame and "grounded". The other wire is spliced to a wire running back to the e-unit. The e-unit is a complex switch that alternates the field and power connections between the motor's two brushes, reversing the motor's direction.

There are a few exceptions to this arrangement, I do not think the 221 motor is one of them.

Thank you guys

I got it.

I was missing the connection between the second brush and the field when I did my checks.

The bottom line is I had to completely disassemble the E unit and polish the contacts.

Larry