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Chapter 17 Belt and Chain Drives Test

INSTRUCTIONS

ANSWER THE FOLLOWING QUESTIONS WITH SHORT, COMPLETE STATEMENTS OR DRAWINGS AS NEEDED ON AN A-SIZE DRAWING SHEET.

QUESTIONS

1. LIST AT LEAST FIVE ADVANTAGES OF GEAR DRIVES.

2. List at least five advantages of belt drives.

3. What would be three disadvantages of belt drives?

4. List at least five advantages of chain drives.

5. Most V-belts function most effectively at what speed and temperature?

6. Are the terms pully and sheave used interchangeably?

7. Define pitch line.

8. What is the function of an idler in belt drive design?

9. Name the three main categories of V-belts.

10. Why are adjustable motor bases used in belt drives?

11. Describe the typical use for flat belts.

12. Describe positive drive belts.

13. List at least five factors that are involved in the selection of a correct belt drive.

14. What is the ratio of the driver pulley to the driven pulley if the driver operates at 2400 rpm and the driver operates at 600 rpm?

15. What is the belt velocity for the driver described in Question 14 if the pitch diameter is 4.5 in.?

16. What is the most commonly used power chain in industry?

17. Define sprocket.

18. The preferred position of chain drive shafts is in a horizontal line or on a line inclined not more than how many degrees?

19. List at least four of the items that must be determined when designing roller chain drives.

20. If a small sprocket has 12 teeth and travels at 1600 rpm and the large sprocket travels at 400 rpm, how many teeth does the large sprocket have?

21. What is the center distance between shafts in chain pitches if the center distance measures 16 in. and a No. 25 chain is used?

22. Why is correct lubrication of chain drives important?

23. Identify at least three methods of lubricating chain drives.

24. When establishing chain length in chain pitches, why is it recommended that the chain length in chain pitches be rounded up to an even number of chain pitches?

Chapter 17 Belt and Chain Drives Problems

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Belt Drive Problems

PART 1: PROBLEMS 17.1 THROUGH 17.9

Solve Problems 17.1 through 17.9 using the information and tables given in this chapter and in Table 17.1 on the next page. All motors are AC motors with normal torque, squirrel cage, synchronous, and split phase; or shunt-wound DC motors; or multiple cylinder internal combustion engines. Include the following information with each solution:

Table 17.1 Nominal center distances, number of belts, and arc length factor chart.

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■ service factor,

■ design horsepower,

■ driven speed,

■ pitch diameter of driver and driven,

■ belt section,

■ number of belts,

■ belt number and center distance,

■ corrected horsepower,

■ belt drive ratio, and

■ belt velocity of driver sheave.

Problem 17.1 A 3 HP, 1750 rpm motor is to operate a furnace blower having a shaft speed of approximately 1115 rpm under normal service. The center distance between the motor and blower shafts is about 16 in.

Problem 17.2 A 3 HP, 1750 rpm motor is used to operate a drill press speed reducer under intermittent service. The spindle speed is about 1136 rpm. The center distance between the motor and spindle shafts is about 18.5 in.

Problem 17.3 A 1-1/2 HP, 1750 rpm electric motor is used to operate a woodworking band saw with the blade turning at 1144 rpm, intermittent service. The center-to-center distance is about 16 in.

Problem 17.4 A 2 HP electric motor with a shaft speed of 1750 rpm operates a printing machine at normal service. The shaft on the printing machine is to operate at 1167 rpm. The center-to-center distance is about 18 in.

Problem 17.5 A 2 HP electric motor with a shaft speed of 1750 rpm operates a punch machine at continuous service. The shaft on the punch machine is to operate at 1108 rpm. The center-to-center distance is about 17 in.

Problem 17.6 A 1.5 HP motor with a shaft speed of 1750 rpm operates a compressor at normal service. The shaft on the

compressor is to operate at 1167 rpm. The center-to-center distance is about 18 in.

Problem 17.7 A 2 HP electric motor with a shaft speed of 1750 rpm operates a printing machine at normal service. The shaft on the printing machine is to operate at 1115 rpm. The center-to-center distance is about 17.5 in.

Problem 17.8 A drive is required for an 18 HP motor driving a fan 16 hours per day. The motor speed is 3600 rpm and the shaft size is 1.625 in. The fan speed is approximately 2250 rpm and the fan shaft is 1.438 in. The center distance is 38 in. minimum and 41 in. maximum.

Problem 17.9 Given the following layout, prepare a detail drawing of the pulley on appropriately sized ASME sheet with border and sheet block, unless otherwise specified by your instructor. (Use units of inches.) Use the sheet size, border, title block, and tolerance instructions provided in Chapter 10,

Dimensioning and Tolerancing.

Part Name: Pulley

Material: Aluminum

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Chain Drive Problems

PART 2: PROBLEMS 17.10 THROUGH 17.16

Solve Problems 17.10 through 17.16 using the information and tables given in this chapter. Include the following information with each solution:

■ service factor,

■ design horsepower,

■ number of teeth drive sprocket and driven sprocket,

■ chain pitch,

■ ratio,

■ center distance in chain pitches,

■ chain length, and

■ lubrication.

Problem 17.10 A chain drive is required for a 1.5 HP electric motor operating a paper machine. The drive sprocket turns 1500 rpm, and the driven sprocket turns 600 rpm. The shaft center distance is about 19 in.

Problem 17.11 A chain drive is required for a 1/10 HP electric motor operating a speed reducer for a belt light package conveyor. The drive sprocket turns 50 rpm, and the driven sprocket turns 17 rpm. The shaft center distance is about 17 in.

Problem 17.12 A chain drive is required for a 1 HP electric motor operating a centrifuge. The drive sprocket turns 10,000 rpm, and the driven sprocket turns 4000 rpm. The shaft center distance is about 18 in.

Problem 17.13 A chain drive is required for a 2 HP electric motor operating a centrifugal pump. The drive sprocket turns 5500 rpm, and the driven sprocket turns 1550 rpm. The shaft center distance is about 14 in.

Problem 17.14 A chain drive is required for a 2 HP electric motor operating laundry machinery. The drive sprocket turns at 1800 rpm, which produces 900 rpm at the driven sprocket. The approximate center distance is 12 in.

Problem 17.15 A chain drive is required for a 2.5 HP internal combustion tractor engine operating a generator. The drive sprocket turns 3000 rpm, and the driven sprocket turns 1800 rpm. The shaft center distance is about 18 in.

PROBLEM 17.16 A chain drive is required for a 2 HP electric motor operating a pure liquid agitator. The drive sprocket turns 2100 rpm, and the driven sprocket turns 700 rpm. The shaft center distance is about 18 in.

DIMENSIONED DETAIL DRAWINGS

Part 3: Problems 17.17 Through 17.23

PROBLEM 17.17 Chain saver (in.)

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PROBLEM 17.18 FWB SD 18 sprocket (in.)

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PROBLEM 17.19 Chain saver sprocket (in.)

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PROBLEM 17.20 Heavy series roller chain (in.) Courtesy HHK Chain Corporation.

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PROBLEM 17.21 Conveyor-type standard roller chain (in.)

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PROBLEM 17.22 Offset sidebar chain (in.)

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PROBLEM 17.23 Sticker chain for the forest industries (in.)

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Math Problems

PART 4: PROBLEMS 17.24 THROUGH 17.29

Find the belt length fxor these pulley radii and center-to-center distances:

PROBLEM 17.24 r = 8", R = 10", d = 27"

PROBLEM 17.25 r = 12", R = 12", d = 100"

PROBLEM 17.26 r = 5", R = 30", d = 40"

PROBLEM 17.27 r = 7", R = 15", d = 30"

PROBLEM 17.28 r = 4", R = 8", d = 35"

PROBLEM 17.29 r = 101.6 mm, R = 203.2 mm, d = 889 mm

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