Basic Principle

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Torque Converter Basic Principle

The presentation describes the basic principle of hydrodynamic torque

converters, operating between a constant speed motor and the driven

machine.

Variable Speed

Constant Speed

Driven

Maschine Speed

Control

Electric

Motor

Hydrodynamic Variable Speed Drive

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Hydrodynamic Torque ConverterFöttinger Principle

DRIVEN MACHINETurbine

Inlet guidevanes

PumpMOTOR

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TurbinePump

Guide wheel

Hydrodynamic Torque Converter

Adjustable guide vanes

AnimationAnimation

GVGV

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Torque Converter Guide Vanes

closed open

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Torque Converter Selection Chart

EL 9

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53

1

1

PD

P

P1 ~ Dp5 ● n1

3

531

PDP

521

PDM

12 MM M1 ~ Dp

5 ● n12

P1 = input power (pump impeller)

n1 = input speed (pump impeller)

= operating fluid density

Dp = torque converter diameter

= power coefficient

M1 = input torque (pump impeller)

µ = torque ratio

Hydrodynamic Power Transmission

M2 = output torque (turbine)

Dp

pump impeller

turbine

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Hydrodynamic Torque Converter Torque Transmission

AnimationAnimation

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Speed and Torque Variation

Belt drive Hydrostatic gear Gear box

Fixed gear ratioi = z1 / z2

n output ~ i

M output ~ 1/ i

A torque converter is a hydrodynamic gear box with stepless speed and torque variation.

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Speed / Torque Curve for different guide vane positions at constant input speed

0

50

100

150

200

250

0 50 100 150

Turbine speed [%]

Tor

que

[%]

Pump torque

Turbine torque

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Speed / Torque Curve for different guide vane positions at constant input speed

0

50

100

150

200

250

Tor

que

[%]

Turbine speed [%]

0 50 100 150

Pump torque

Turbine torque

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Speed / Torque Curve for different guide vane positions at constant input speed

0

50

100

150

200

250

Tor

que

[%]

0 50 100 150

Turbine speed [%]

Pump torque

Turbine torque

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Speed / Torque Curve for different guide vane positions at constant input speed

0

50

100

150

200

250

Tor

que

[%]

0 50 100 150

Turbine speed [%]

Pump torque

Turbine torque

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Speed / Torque Curve for different guide vane positions at constant input speed

0

50

100

150

200

250

Tor

que

[%]

0 50 100 150

Turbine speed [%]

Pump torque

Turbine torque

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Speed / Torque Curve for different guide vane positions at constant input speed

0

50

100

150

200

250

Tor

que

[%]

0 50 100 150

Turbine speed [%]

Pump torque

Turbine torque

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Speed / Torque Curve for different guide vane positions at constant input speed

0

50

100

150

200

250

Tor

que

[%]

0 50 100 150

Turbine speed [%]

Pump torque

Turbine torque

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Speed / Torque Curve for different guide vane positions at constant input speed

0

50

100

150

200

250

Tor

que

[%]

0 50 100 150

Turbine speed [%]

Pump torque

Turbine torque

AnimationAnimation

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Typical Load Curves of Driven Machines

M2 = f (1/n2)

M2nM2 = constant

M2 = f (n22)M2

n2 n2n

Constant torque

Parabolic torque

Hyperbolic torque

Torque converters are mainly used on hyperbolic or constant torque applications or any mixed characteristic.

They provide a wide speed range and a flat efficiency curve.

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