Allis Chalmers

Question 1

Although vertical Hydro-unit machines may be extremely large:

Answer 1

close tolerances must be maintained

Question 2

The vertical Hydro-unit machine that has the thrust bearing and upper guide bearing located above the rotor is called:

Answer 2

Suspended type

Question 3

On large low-speed vertical Hydro-unit machines, the rotor poles are secured to the rim by:

Answer 3

Driven tapered keys

Question 4

On an adjustable-blade pump or propeller (Kaplan) type turbine, a hollow shaft is required on the electrical machine to:

Answer 4

allow oil pipes to be carried through the shaft from the oil head at the top of the unit to the turbine servomotor

Question 5

On guide bearings, lubrication arrangements eliminate the need for an oil circulating system. The designated oil level is usually about ___ the length of the bearing above its lower end

Answer 5

1/3

Question 6

Brakes are usually operated by compressed air at ____ psi. When used as jacks, the brakes are operated by an oil pressure of ___ psI.

Answer 6

75-100; 1000-3500

Question 7

High-pressure bearing lubrication is frequently used to reduce:

Answer 7

Breakaway torque

Question 8

The high-pressure bearing lubrication pump assembly uses a ____ to prevent starting the machine (hydro-unit) until the pressure is approximately 1000 psi.

Answer 8

Pressure switch

Question 9

Prior to erection of the unit, the turbine or pump runner and shaft are centered and supported in a position at a specified distance usually ___ inch below the correct operating position.

Answer 9

1/4 to 3/4

Question 10

During the alignment process, fins should be provided on the plumb bob to allow it to hang in a pail of heavy oil to dampen any swings and protect the plumb line from:

Answer 10

all strong air currents

Question 11

Electric welding on any part of the machine is a serious hazard to bearings. A bearing surface can be damaged:

Answer 11

rapidly if welding current passes across it

Question 12

In regards to Hydro-units, if possible all electric welding should be done:

Answer 12

Before bearings are assembled

Question 13

The thrust bearing tub cooling coil should be water tightness tested to a water pressure of _____ % of normal working pressure

Answer 13

150

Question 14

Precautions should be taken during assembly of the thrust bearings to avoid

Answer 14

All of the above

Question 15

Segmental bearings made up of independently adjustable segments must be set to:

Answer 15

Proper elevation and clearance

Question 16

To eliminate the possibility of shaft current, bearings and other parts should be:

Answer 16

Insulated

Question 17

Check the insulation with a ___ volt insulation meter, if the resistance is less than ____ ohms inspect the insulation and make necessary corrections.

Answer 17

500; 20000

Question 18

Before drawing the couplings together, their mating surfaces must be in alignment, parallel, clean and free from burrs. The couplings must be drawn up

Answer 18

evenly to prevent distortion

Question 19

Coupling bolt tension can be determined by an accurate measurement of the bolt:

Answer 19

Elongation

Question 20

To prevent plumb wires from swaying and twisting, the finned weights should be immersed in pails off

Answer 20

Oil

Question 21

Check commutator ____ with a dial indicator rather than by visual observation.

Answer 21

Run out

Question 22

Various instruments and relays and their associated equipment, wiring, piping and conduit should be carefully installed, making sure that it does

Answer 22

not short-circuit the bearing insulation

Question 23

The rotating parts of the machine must be in ____ balance and may require the addition of weights to the motor

Answer 23

Dynamic

Question 24

Before connecting the generator to the power system check

Answer 24

Phase frequency

Question 25

If an operational check of the shaft run-out is required, make it after the generator.

Answer 25

Is operating under full load