Advanced Alignment

Question 1

Define Thermal Growth

Answer 1

small movements that occur in all types of industrial equipment due to temperature changes

Question 2

What is the formula for determining Thermal Growth?

Answer 2

Change in length = original length x change in temp x coefficient of expansion

Question 3

What are some possible causes of a rise in temperature of a machine?

Answer 3

Steam, compression, chemical reaction, electrical load, friction, and possibly the removal of heat.

Question 4

Is the quick hot alignment method a reliable method of alignment?

Answer 4

No, this method is unreliable and rarely works.

Question 5

Online hot alignment checks require some permanent measuring devices to be mounted on the machine, name the most common methods of this.

Answer 5

optical, laser, proximity probes with a water cooled stand, Dodd bars, benchmark gauges, instrumented couplings

Question 6

What must be completed before conducting online benchmark procedures?

Answer 6

an acceptable cold alignment

Question 7

What planes do two coupled machines share a common centreline on?

Answer 7

vertical and horizontal planes

Question 8

When performing an alignment, what do you do to a set of machines that are affected by thermal growth?

Answer 8

intentionally misalign (offset) at coupling to accommodate the thermal change

Question 9

How precise of an alignment is required on a motor and pump with a vertical mount?

Answer 9

A precision alignment just like a horizontal unit

Question 10

What is the most common sympton of vertically and horizontally misaligned shafts while running?

Answer 10

an increase in vibration levels

Question 11

What is the purpose of online coupling monitors?

Answer 11

to check alignment when machines are running

Question 12

In a crossdial alignment, which dial is known as the “King” dial and where is it mounted and zeroed?

Answer 12

The “A” dial, it’s mounted on the shaft of the MTBM (reading off the fixed machine), and is normally zeroed at 12 O’clock

Question 13

What are the 3 types of shaft misalignment and which is the most common?

Answer 13

The 3 types are angular, offset, and combination. Combination is the most common.

Question 14

What dimension is increased to make a crossdial alignment more accurate?

Answer 14

the distance between the two dials, usually indicated as “X” in the crossdial formula