OILING.--Fill the oil wells to the overflow before starting and keep them full. Use good "dynamo oil." Be sure that the oil rings turn freely while the motor is running. If in a dirty place, draw off the old fluid and fill with new every two or three months.
CARE OF MOTOR.--The motor must be kept clean. If the commutator become rough, smooth it up with No. 00 sandpaper moistened with oil. When fitting new brushes or changing them, always sandpaper them down until they fit the commutator perfectly, by passing to and fro beneath the brush a strip of sandpaper, having the rough side toward the brush.
Brushes must always be renewed before the metal of the holder comes in contact with the commutator.
Don't use anything on commutator except good mineral machine oil, or kerosene, and this only in very small quantities applied with a cloth having no lint or threads.
Fig. 766.--Sectional view showing principal parts of Reliance adjustable speed motor: 1, lever fulcrum pin; 2, lever; 3, sliding thrust bearing box; 4, ball bearing; 5, armature shaft end nut; 6, cap; 7, commutator end yoke; 8, lever rod; 9, compression spring; 10, steel frame; 11, speed adjustment nut; 12, thrust collars and pins; 13, hand wheel rod; 14, hand wheel; 15, sleeve nut; 16, oil well cover; 17, bearing bushing; 18, sleeve; 19, oil ring; 20, pinion end yoke; 21, rocker arm; 22, brush holder stud; 23, brush; 24, commutator; 25, armature; 26, armature laminations; 27, armature coils; 28, armature end plate; 29, armature shaft; 30, leads; 31, axial position of commutating pole; 32, axial position of main field pole; 33, slide rail screws; 34, end yoke cap screws; 35, slide rails; 36, commutating coil; 37, commutating pole; 38, main field pole; 39, main field coil.
Fig. 767.--Cutler-Hammer reversible starter with no voltage release, adapted to start and operate motor at full speed in either direction, such for instance as motors driving auxiliary motions on lathes, planers and other machine tools which may rotate in either direction but always at constant speed. They are not designed to reduce the speed of the motor, but merely to start it and bring it smoothly up to full speed in either direction. Two no voltage release latching devices are provided so that the lever will be held in the full speed position in either direction so long as the voltage of the line remains constant. On failure of voltage a strong centering spring attached to the hub-post of the lever throws the latter to the central, or off position. The shunt field circuit is not opened by starters of this type.