Spaceel

I am looking for some information about the use of War Leonard Control in the field of EE.

If anyone know something about it, please put some here.

Reply

I have put Ward leonard control on my watch list. I suggest that you read Harry Ward Leonard more carefully. Other related articles include:

Adjustable-speed drive

Brushed DC Electric Motor

Electric motor

Electronic speed control

Motor controller

Thyristor drive

When you post to discussion pages, please sign your post by putting 4 tildes at the end (like this: ~~~~). C J Cowie 14:30, 13 October 2007 (UTC)

Introduction

Ward Leonard Control, also known as Ward Leonard Drive System, is widely used motor speed control system that was introduced by Harry Ward Leonard in 1891. Applications of the control system include elevators and many others. Even though the system started to be replaced from 1980s, many variations still remain in use and are also considered to be Ward Leonard Control. Spaceel 00:28, 15 October 2007 (UTC)

Basic Concept

A Ward Leonard control system has a electrical generator and a electric motor. Prime mover feeds a constant DC current to a generator. The generator is connected to the armature of the motor. The speed of motor is controled by varying the voltage feeded from generator. Fig 1 shows the Ward Leonard control system, with the V_g^f feeding the generator and V_m^f feeding the motor. Spaceel 00:28, 15 October 2007 (UTC)

Mathmetical Approach

Before going into the equations, first conventions should be set up, which will follow the convention Datta used. The first subscripts 'g' and 'm' each represents generator and motor. The superscripts 'f', 'r',and 'a', correspond to field, rotor, and armature.

W_i = plant state vertor K = gain t = time constant J = polar moment of inertia D = angular viscous friction G = rotational inductance constant s = laplace operator

eq 1: The generator field equation

     Vgf = RgfIgf + LgfIgf

eq 2: The equation of electrical equilbrium in the armature circuit

     -GgfaIgfWgr + (Rga + Rma)Ia + (Lga + Lma)Ia + GmfaImfWmr = 0

eq 3: Motor torque equation

     -TL = JmWmr+DmWmr

With total impedence, L_g^a + L_m^a, neglected, the transfer function can be obtained by solving eq 3 T_L = 0.

eq 4: Transfer function

    ${\frac {W_{m}^{r}(S)}{V_{g}^{f}(S)}}={\cfrac {K_{B}K_{v}/D_{m}}{(t_{g}^{f}s+1)[t_{m}s+{\cfrac {K_{m}}{D_{m}}}]}}$

$K_{B}={\tfrac {G_{m}^{f}aV_{m}^{f}}{R_{m}^{f}(R_{g}^{a}+R_{m}^{a})}}$

$K_{v}={\tfrac {G_{g}^{f}aW_{g}^{r}}{R_{g}^{f}}}$

$t_{m}={\tfrac {J_{m}}{D_{m}}}$

$t_{g}^{f}={\tfrac {L_{g}^{f}}{R_{g}^{f}}}$

$K_{m}=D_{m}+K_{B}^{2}(R_{g}^{a}+R_{m}^{a})$

Spaceel 00:29, 15 October 2007 (UTC)

See also

• Motor-generator
• Rotary transformer
• Booster (electric power)
• Harry Ward Leonard

References

Citations

General references

• Leonard, H. Ward (2006). "Descendants Of William Ward of Sudbury Born Abt 1603, and Other Related Families". rootsweb.com. Retrieved 2006-08-08. {{cite web}}: Check date values in: |date= (help)
• The Editors (Nov 1989). "Technology for Electrical Components". Power Transmission Design: 25–27. {{cite journal}}: |last= has generic name (help); Cite has empty unknown parameter: |coauthors= (help)

Leonard, Harry Ward

Ward Leonard Control

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