WEIGHT-GOVERNOR 9L4989 - Caterpillar

Coil - an insulated conductor that is wound in a series of turns. Coils form the windings of the generators. The voltage can be varied by varying the number of turns in a coil. Typically, the number of coils is equal to the number of slots. Refer to Illustration 6.Coil Group - a number of adjacent coils in the same phase. A coil group lies between other coil groups which are in different phases. The number of groups is equal to the number of poles multiplied by the number of phases.Coil Span - the number of slots spanned by a coil. For example, a coil span of 5 is the same as the coil throw 1-6. Refer to Illustration 6.Coil Throw - the distance between the two sides of the coil, which is expressed by numbering the slots that the two sides of the coil occupy. For example, a coil with a coil throw 1-6 would occupy the two extremes of a slot sequence that is numbered 1-6. Refer to Illustration 6.Coils Per Group - This parameter shows how many coils are in any specified group. Coils/Group can be calculated by dividing the total number of coils by the number of groups.Concentric Winding - In a concentric winding, each coil group comprises coils of different spans which are sharing a common center line. Thus, coils are routed in loops that are enclosed within larger loops. Therefore, the coil throw may be expressed as a decimal number. This method of winding requires the least amount of copper and results in slightly higher levels of harmonics. Refer to Illustration 4.Copper Weight - total weight of the wire.Exciter Frequency - exciter armature operating frequency.Exciter Poles - number of magnetic poles in the exciter field.Field Lead Resistance at 25 °C (77 °F) - resistance measured at the lead terminals of the field.HF - an abbreviation for heavy film wire.Group - same as coil group.Inside Connection - the number of stator coils in each phase and the coil connections needed to make up one phase for a high voltage star configuration.Insulation - There are two main types of wire insulation that are used on Caterpillar generators: Heavy Polyester Polyamide Imide and Heavy Nytherm. These insulation types can be either class H or class F materials. Class H is temperature rated at 180 °C (356 °F). Class F is temperature rated at 155 °C (311 °F).Lap Winding - a winding in which one side of each coil, where it emerges from each end of the slot, lies above the nearest coil. The opposite side of the coil lies underneath the nearest coil. Lapped windings are routed across one another. The coil throw is a whole number. This method of winding provides a better waveform because of better symmetry. Refer to Illustration 5.Layer (Form) Wound - method of placing large single wires in uniform and in parallel layers. Layer winding utilizes square, rectangular, or round wires which can be placed very close to one another