﻿GET_GEVOMechL2_08_01_01_87 - ANIMATION Screen
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You have reached the end of this module!

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In this module, you learned to:

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State the purpose of the traction motor combo.

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The main purpose of the traction motor combo is to convert electrical energy to mechanical energy for driving the locomotive wheels, a process referred to as motoring.

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The traction alternator supplies the electrical energy.

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The secondary purpose of the traction motor combo is to convert the mechanical energy of slowing a moving locomotive to electrical energy utilizing a process referred to as dynamic braking.

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In dynamic braking, the traction motors function as generators with the electrical energy that they produce dissipated as heat in the dynamic braking resistor grids.

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Describe the major components of a traction motor combo.

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The traction motor takes electrical energy from the propulsion system and converts it into mechanical energy for driving the locomotive wheels.

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The bull gear, pressed onto the axle, meshes with the pinion gear on the traction motor rotor to transfer the torque of the traction motor to the axle.

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The axle is used to transfer the rotational force of the traction motor to the wheels.

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Journal bearings, located on each end of the axle, allow the axle to turn with minimal friction when mounted inside the journal boxes attached to the truck frame.

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The locomotive rides on the tread of the wheel, and the wheel flange keeps the locomotive on the rails.

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The U-tube, mounted to the traction motor, wraps around and houses the axle.

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The U-tube contains two roller bearing assemblies that support the traction motor and allow axle rotation within the U-tube.

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The gear case protects the pinion and bull gears from the outside environment.

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Additionally, the gear case contains the oil used to lubricate the two gears.

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On AC traction motors, the oil also lubricates the pinion end bearing in the traction motor.

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The gear case consists of two halves, a top or upper half and a bottom or lower half, which are bolted together.

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Identify the running maintenance requirements for the traction motor combo.

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Traction Motors

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Every 92 days, in DC traction motors, check for loose or missing traction motor commutator covers, check commutator for discoloration and damage, and check for chipped, broken, or damaged brushes.

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For both AC and DC traction motors, check power leads for abrasion damage and rubbing against other cables or truck parts.

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When renewing wheels, visually inspect and run traction motors with no load.

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Check armature bearings for unusual noises and binding and vibration.

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Check commutator smoothness and resurface, if necessary, using jig grinding device.

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Clean insulators.

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Blow out debris with compressed air.

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Repair covers as required.

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Traction Motor Combo

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Every 92 days, inspect gear cases for mechanical damage.

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Check for damaged or missing fill or drain plugs.

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Clean metal particles from drain plug if removed.

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Inspect the entire combo for excessive oil leakage.

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Check oil level in the gear case.

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Fill oil to the indicated level below the bottom of the fill opening.

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If oil loss is greater than limits, remove traction motor combo and inspect it.

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Every 92 days, inspect gear case mounting bolts and U-tube to traction motor mounting bolts for tightness by hand or a wrench.

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Check for any gap in the joint visually, by performing a hammer test, or by using a 0.005-inch feeler gauge.

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If parts are loose, broken, or missing, replace with new parts.

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Tighten all the bolts to the specified torque values.

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Every 92 days, check accessible gear case split line bolts for looseness by hand or wrench or perform an 8-ounce hammer test.

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If parts are loose, broken, or missing, replace with new parts.

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Tighten all the bolts to the specified torque values.

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Annually, drain and refill the gear case.

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When renewing wheels, renew gear case seals.

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Drain and refill the gear case.

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Clean and inspect the pinion and bull gears for wear and damage.

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Wheel

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Daily or per trip, visually inspect the wheel rim versus the witness groove for wheel wear.

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Check for cracks, shelled treads, or flat spots.

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Make corrections as required.

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Describe the basic operation of a traction motor combo.

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Electricity is supplied to the traction motor from the propulsion system.

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Coils in the traction motor create a magnetic field, which causes the rotor to turn.

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On the rotor, the small pinion gear meshes with the larger bull gear on the axle.

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Depending on the traction motor design, the pinion gear may either be formed as an integral part of the rotor or may be pressed onto the rotor.

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The bull gear is pressed onto the axle along with the two wheels and the U-tube.

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Two roller-bearing assemblies allow the axle to rotate freely within the U-tube while the two journal bearings allow the axle to rotate freely within the journal box mounted to the truck.

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With the traction motor powered, the pinion and bull gears mesh, causing the axle and wheels to turn and power the locomotive.
