10. With the motor armature (with the 



■ rotor spacer in place) push the 



keeper out of the motor field. 



ATTENTION: Removing the keeper 

 without substituting 

 it with the field; 



- or placing the field 

 on steel shelves or 

 benches, unless sep- 

 arated from the 

 steel by at least 

 one-half inch of 

 nonmagnetic material; 



- or letting the field 

 come in contact with 

 the ferrous tools or 

 measuring instruments 



will demagnetize the field up to 



50%. 



HANDLING. STORAGE, INSTALLATION 



Greater care is required for handling frameless dc 

 torque motors than for housed units or conventional 

 ac motors. The armature field and brush assembly are 

 supplied as a matched set identified serially and should 

 not be interchanged with other components. They are 

 packaged separately in the shipping container. During 

 unpacking and handling and throughout installation 

 care must be taken to avoid bending or distorting the 

 brush assembly springs and to protect the commu- 

 tator surfaces from scratching or contamination by oil 

 or fingerprints. The field is supplied with a "keeper" 

 ring attached by magnetic force, which must not be 

 removed until the field is installed and the armature 

 is in place. To do so will result in approximately 1/3 

 reduction in torque sensitivity. 



Frameless units should be stored in nonmagnetic 

 racks or containers - the shipping container is suit- 

 able — to prevent interaction of magnetic fields. 

 Attraction of magnetic particles also should be 

 avoided. Protect the armature core from moisture with 

 desiccant. 



COMPONENT PARTS- 

 DEFINITIONS 



Armature. The rotating element. The windings are in 

 this part. 



Commutator. A conductive segmented ring on the 

 armature, which allows electrical power to be trans- 

 ferred to the winding from the stationary elements. 

 Field. The stationary permanent magnetic flux field in 

 the motor air gap. 



Brush Assembly. The stationary insulating ring, or 

 segment supporting spring-loaded electrical contacts 

 (brushes), which slide on the communicator to transfer 

 the dc power. 



Keeper. A magnetic steel ring installed on the field to 

 keep the magnets at full strength until the armature is 

 fully in place. The normal keeper type is shown in the 

 above installation instructions. Other types sometimes 

 are used for magnetic or assembly reasons. 



36 



