Variable-speed Power Transmision Devices

Question 1

What are the current designs of variable speed drives?

Answer 1

Variable frequency drives

Vector

Servo

AC

DC

Question 2

Wide belt drives have a ratio range of?

Answer 2

1:1 up to 8:1

Question 3

Variable speed mechanical drives must be adjusted when?

Answer 3

Machine is running

Question 4

23 22v 721

Wide belt numbering

What do those number mean?

Answer 4

23 = belt top width in 1/16 of an each (1 7/16”)

22V = included angle 22 degrees

721 = pitch length 72.1”

Question 5

These adjustable drives use an adjuster on one pulley which is manually adjusted to set input to output speeds?

Answer 5

Narrow belt drives

Question 6

When are variable speed drive chains used?

Answer 6

Applications below 3000rpm where speed, positive drive, accuracy and long life are required.

Question 7

Variable speed chain drives don’t slow down as load increases? True or false

Answer 7

True

Question 8

After how many hours should oil be changed in chain drives?

Answer 8

2000

Question 9

How do variable spill hydraulic drives change the output speed and power?

Answer 9

By changing the amount of oil contained in the rotating case.

Question 10

These drives are designed to have a constant input speed of 1760 rpm and output speed of 0 to 1760 rpm?

Answer 10

Variable-speed wet disc drives

Question 11

When doing a service on a variable speed chain drive 15000-20000 hour over haul and you find metal flakes in the oil. Is this normal?

Answer 11

Yes

-clean exterior

• drain oil
• remove top cover
• place unit on its side
• remove chain and inspect
• replace worn parts along with chain and bearings
• roll using over by hand After re assembly and adjust chain tension to about 2%
• fill with oil and run on a test bench