Siemens A1 Manual De Usuario
International English
Introduction
MICROMASTER Applications Handbook
1
1 Introduction
This manual is intended to help users of variable speed drives successfully install
and utilize Siemens Standard Drives.
and utilize Siemens Standard Drives.
It includes an introduction to drives, which may be informative to first time users.
Detailed technical information and complete parameter descriptions are available
in the Reference Manual and the Parameter List.
in the Reference Manual and the Parameter List.
INTERNET Address:
These sites will allow access to handbooks, application and training information, as
well as Frequently Asked Questions. (FAQs).
well as Frequently Asked Questions. (FAQs).
1.1
What is a Variable Speed Drive?
A Variable Speed Drive (VSD) consists of a Motor and some form of controller.
Early electric VSDs consisted of AC and DC motors combinations which were used
as rotating controllers. The first electronic controllers used Thyristor (SCR)
Rectifiers which controlled the voltage, and therefore the speed of DC motors.
These DC VSDs are still widely used and offer very sophisticated control capability.
Early electric VSDs consisted of AC and DC motors combinations which were used
as rotating controllers. The first electronic controllers used Thyristor (SCR)
Rectifiers which controlled the voltage, and therefore the speed of DC motors.
These DC VSDs are still widely used and offer very sophisticated control capability.
However, the DC motor is large, expensive and requires periodic brush
maintenance. The AC induction motor is simple, low cost, reliable and widely used
throughout the world.
maintenance. The AC induction motor is simple, low cost, reliable and widely used
throughout the world.
In order to control the speed of an AC induction motor a more complex controller,
usually called an inverter is required.
usually called an inverter is required.
In order to understand how an inverter works, it is necessary to understand how an
induction motor works.
induction motor works.
An induction motor works like a transformer. When the stator (the fixed, outer
winding) is connected to a three-phase power source, a magnetic field is set up
which rotates at the frequency of the supply.
winding) is connected to a three-phase power source, a magnetic field is set up
which rotates at the frequency of the supply.
Figure 1-1 shows a simplified cross-section of an induction motor.
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2
3
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2
3
Stator Windings
Air Gap
Rotor
Shaft
Figure 1-1
Induction Motor. Simplified Cross Section