Card Set Information
What function do bearings serve within a generator or motor?
They are designed to allow a rotating armature or rotor to turn freely within the motor.
What are the two most common types of bearings found in motors and generators?
Friction and Antifriction bearings.
What are two types of antifriction bearings?
Roller or Ball type.
What type of bearing consists of two hardened steel rings, hardened steel rollers or balls and separators?
What is the difference between a ball bearing and a roller bearing?
A ball bearing carries the load on two tiny spots diametrically opposite, while a roller carries the load on two narrow lines.
Determining which type of ball or roller bearing to use is dependent on what factor?
By the load it was designed to carry.
What are the three forces that can effect ball or roller bearings?
Radial, axial thrust, and angular contact.
A load that is a result of forces applied to the bearing perpendicular to the shaft is known as what type offeree?
A combination of radial and thrust loads create what type offeree on a bearing?
What type of bearing would be installed on a vertically mounted motor?
Horizontal motors use what type of motor bearings?
What type offeree is the result offerees applied to the bearing parallel to the shaft?
What is the easiest way to determine bearing wear on an operating motor?
By periodically feeling the bearing housing for overheating or excessive vibration.
A simple way to sound test a bearing is by what method?
By placing one end of a screwdriver against the bearing housing and the other end against the ear.
Motor bearings are lubricated IAW what technical guidance?
Most motor bearings are lubricated within what periodicity?
What NSTM can be used to find general information on all types of bearings?
How do manufacturers' identify bearings?
By use of a three digit basic bearing number.
Bearings should be stored in a dry environment and never exceed what storage temperature?
120 Deg. F.
If a high bearing temperature is reached within the first 10 to 15 minutes of operation this can indicate what?
A serious overheating problem.
A motor shaft that has no vertical movement is an indication of what?
Excessive end-play on a generator can be corrected by what?
By adding shims.
What are two methods of bearing installation?
Arbor press and heat method.
When using the arbor press method to install a bearing onto a shaft, pressure is always applied to what part of the bearing?
To the inner ring.
When pressing a bearing into a housing using the arbor press method, pressure is applied to what part of the bearing?
The outer ring.
When heating a bearing in a temperature-controlled furnace, the temperature must never exceed?
203 Deg. F +-10 F.
What are three types of friction bearings?
Right line, journal and thrust.
Prolonged heating of a bearing in a temperature-controlled oven could have what detrimental effect?
Deterioration of the prelubrication grease.
How can you determine bearing wear on a sleeve bearing?
By measuring the air gap at each end of the machine.
When removing bearings from a motor using an arbor press care should taken to place the flat steel blocks in what location?
Under the inner ring.
When renewing grease on a bearing with outer bearing caps, what type of oil is used to flush the bearing cap upon disassembly?
Do permanently lubricated bearings require periodic grease renewal?
Never add lubricate to this type of bearing.
How is a bearing removed that has seized to an operating shaft?
By use of a cutting wheel.