Perhaps this is how a startrek type tractor beam could work?
1) charge the target object with a cathode ray gun to give it a negative charge.
2) sweep magnetic fields across it, possibly just move a bar magnet on a race track. Then the by reversing the rotation of the sweeping magnetic fields, the target object could be pulled or repelled.
we could sweep the magnetic field across the object, perhaps by holding a bar magnet and swinging it in a circle.