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Introduction

Our method of teaching fluid power is to emphasize the practical, everyday aspects,and to avoid theory and mathematics as much as possible. So this is not a book for

scientific study; it is a textbook, a reference, and a guide for those who intend toactually use fluid power.

Our Volume fluid power school is offered for people who have completed our other

courses or who have a good background in fluid power. ! prior knowledge offundamentals is important; they were covered in previous courses and will not be

repeated.

Sub"ect matter will be almost entirely on hydraulics except for a brief treatment of

air motors. #he ma"ority of the material will cover rotary output of hydraulic systems$ hydraulic motors and hydrostatic transmissions $ but we will include some unusual

and interesting topics as shown in the curriculum below.

%ho will benefit from this course& 'esigners, and engineers who will be designing

e(uipment or working with e(uipment using rotary output. !lthough this is notprimarily a study of troubleshooting or maintenance, an understanding of hydraulicmotors and transmissions will certainly benefit anyone who must service this kind of

e(uipment. #here will be many illustrative circuit diagrams and design tables. f you

have a pocket calculator, bring it to class. )ut this is not necessary; calculations willinvolve only elementary mathematics.

%ho should not enroll& #hose whose main interest is in installation, maintenance,and troubleshooting will derive only a limited benefit. #hose people "ust starting in

fluid power are advised not to enroll.

Curriculum For Volume III Fluid Power School

Volume of the %omack textbook series ndustrial *luid +ower will be used for thiscourse. %e will cover as much of the book as time permits. !bout - of the course

will be on hydraulics, with a brief look at air motors and their operation. %e expect tofeature the following and other topics/

Lesson 1

0ydraulic motor types and comparison of their characteristics; application examples;

design steps for a hydraulic motor system; performance of a hydraulic motor;

relationship of 0+, tor(ue, and speed; porting loss; tor(ue conversion; etc.

Lesson 2

0ydraulic and electric motors compared; determination of motor tor(ue; estimating0+ input; vehicle drive calculations; road traction; rolling resistance; load

distribution; hydraulic motors on winches.

Lesson 3

1atalog selection of hydraulic motors; directional control of motors; cushioned

stopping; overrun limiting; se(uential operation of motors; methods of motor speedcontrol; step control; improving speed regulation and circuit efficiency; life

expectancy; tor(ue to accelerate a load, etc.

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Lesson 4

'efinition and advantages of closed loop circuits; pumps and motors for closedloops; a step$by$step construction of hydrostatic transmission circuits; variable

motors in transmissions; heat removal from closed loops; cylinders in closed loops,etc.

Lesson 5

!ir motor selection and operation; directional control of air motors; speed control of

air motors; rotary actuators; direction and speed control of actuators; speed and

tor(ue of actuators; rotary flow dividers; spool$type flow dividers; priority type flowdividers.

Lesson 6

*low divider circuits and applications; power steering systems and components;design calculations for power steering; bootstrapping defined; tension stressing;

hydraulic tensioning; torsion stressing; variable displacement motors inbootstrapping; self$activated torsion stressing.