1.Fundamentals Coupling

7/28/2019 1.Fundamentals Coupling

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Fundamentals Fluid Coupling


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Change of speed of the working machine

Voith VariableSpeed Drive

Motor

constant speed

working

machine

Power range up to 50 000 kWSpeed range up to 20 000 rpm

constant speed variable speed

What does variable speed mean ?


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Fttinger Principle

drive with constant speed

Driver (electric motor)

Working

machine


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Working

machine

hydro-dynamic system

PumpTurbine

Fttinger Principle


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Working

machine

hydro-dynamic system

Pump Turbine

Fttinger Principle


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Primary Wheel Secondary Wheel

Oil Flow

The Principle of

Hydrodynamic Power Transmission

Fttinger principleMovie
http://localhost/var/www/apps/conversion/tmp/scratch_5/How_they_work_T_couplings_Ausschnitt.wmvhttp://localhost/var/www/apps/conversion/tmp/scratch_5/How_they_work_T_couplings_Ausschnitt.wmv


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P = Pump

T = Turbine

S = Scoop tube

Constant Filling Variable Filling

Basic design of Couplings

Animation
http://localhost/var/www/apps/conversion/tmp/scratch_5/svtl.exehttp://localhost/var/www/apps/conversion/tmp/scratch_5/svtl.exe


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Scoop tube principle


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Operating ranges:

I, IV Starting range

II Control range

Typical load curves

1.Constant torque (e. g. positive

displacement pumps and

compressors)

2.Decreasing torque (e. g. boiler

feed pumps operating at varying

pressure)

3.Parabolic torque (resistance

parabola, pumps without back

pressure, fan)

4.Decreasing torque (e. g. Boiler

feed pumpsat fixed pressure

operation)

III Overload range

Torque curves


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Smin= (1 - n2/n1) x 100 % Minimum slip

n1 = Input speed

n2 = Output speed

The operating range is

limited by :

Characteristic curve

100% scoop tube

position with max.

output speed

Characteristic curve 0%

scoop tube position with

min. torque required

Torque curves


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System curve Coupling curve Drive speed


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Change in system Speed reduction Scoop tube regulation

to origin speed


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Change in flow

Speed change

Speed raise Scoop tube regulation

to higher speed


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Design and Operation

Scoop tube

Scoop tube positions

3 Scoop tube

4 Oil ring

5 Scoop tube position- 0%6 Scoop tube position-100%

Animation
http://localhost/var/www/apps/conversion/tmp/scratch_5/svtl.exehttp://localhost/var/www/apps/conversion/tmp/scratch_5/svtl.exe


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Integration of the Variable-Speed Turbo Coupling

into a control circuitPosition control circuit

Components:

Position controller

Actuator for continuous

control

Position feedback


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Integration of the Variable-Speed Turbo Coupling

into a control circuitProcess control circuit

Components: Position controller

Process controller


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Fields of application

Oil and Gas

- Crude-oil pumps

- Injection pumps

- Compressors


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Chemical Industry

- Compressors

- Pumps

- Centrifuges

- Fans


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Steel and iron industry

- Compressors

- Fans

- Pumps


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Material Handling

and Conveying

- Conveyor drives

- Pipeline pumps

- Fan drives

- Pipeline compressors


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Fields of application Conveyor drives


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Fields of application Coal Mills


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Fields of application Fan Drives


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Fields of application Pump Drives


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Slip losses within coupling PV

0

20

40

60

80

100

0 20 40 60 80 100

n2/n1 * 100%

Power%

Power losses for working machines with parabolic torque characteristics

P2max

P1max = P2max/ (n2/n1)^3

P1 = P2/ (1-s)

Pv

= P1

- P2

P2 = P1max * (n2/n1)^3

Pvmax

P1P2

Pv

s= 1-n2/n1

P1max

s

66

P2max

2/3 * n1

Pvmax


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Variable Speed Coupling, Hydraulic losses

P1

P2

Plosses

n2n1

100%23

n1

Maximum

Power losses for working machines with parabolic torque characteristics


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Oil Circuit Power Losses


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The driven machine describes the characteristic output torque!!

Motor

Pump

P1,M1,n1,w1 P2,M2,n2,w2Pv

Applies only for

parabolic output

torque!Pv

P=Power [kW], M=Torque [Nm], n=Speed [1/min], w=angular velocity [1/s]


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Applies only for

parabolic output

torque!

P1 = M1 * p *n1/30

P1 = M1 * w1

P2 = M2 * p *n2/30

P2 = M2 * w2

M1 = M2 = M

Pv = P1 P2 = M1 * w1 M2 * w2

Pv = M * (w1w2)

Pv

M2= k * w2^2 = M

Pv

= k * w2

^2 * (w1

w2

) = k * w1

* w2

^2 k * w2

^3

Pv`= k * w1 * 2 * w2 k * 3 * w2^2 Pvmax`= 0

k * w1 * 2 * w2 = k * 3 * w2^2

2 * w1 = 3 * w2

w2 = 2/3 * w1The maximum slip losses Pv are at 66% output speed

(approx. 40% scoop tube position)


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The maximum slip losses Pv are at 66% output speed

(approx. 40% scoop tube position) at parabolic output torque


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Documents

1.Fundamentals Coupling