Earthing System TN-C-S

Motor Control Diagrams

Motor starters

Star-delta starter

 

This is the most popular and commonly

used starting method for motor ratings

> 4 kW (400 V).

 

• Electronic motor starter (EMS) and soft

starter

These enable the soft and low-noise

starting of the motor. This eliminates

interference producing current peaks

and jerks during switching. The startup

and deceleration phase of the motor can

also be time-controlled depending on the

load.

 

• Frequency inverter

This enables time-controlled motor

starting, motor braking and operation

with infinitely variable motor speeds.

Depending on the application, different

types of frequency inverters are used:

– with the voltage/frequency control

(U/f) or vector control for

frequency-controlled motor operation,

– with vector control or servo control for

high speed accuracy and additional

torque adjustment.

Associated circuit diagrams

Direct on line starter

Direct-on-line starter

 

In the simplest case the motor is

connected directly with a contactor. The

combination of motor protection and

cable protection (fuse) is called a motor

starter (MSC = Motor Starter

Combination).

By applying the full mains voltage to the

motor windings, DOL starting may

produce large starting currents which

may result in troublesome voltage

changes. Direct-on-line starting

three-phase motors must not cause

interference voltage changes in the

public utility grid. This requirement is

generally fulfilled if the apparent power

of a three-phase asynchronous motor

does not exceed 5.2 kVA or its startup

current does not exceed 60 A.

With a mains voltage of 400 V and 8 times

the starting current, this corresponds to

a rated motor current of around 7.5 A and

thus a motor rating of 4 kW.

The motor rating denotes the mechanical

output of the motor at the shaft.

CB Number of poles

Standards

CE

The CE conformity marking shall indicate conformity to all the obligations imposed

on the manufacturer, as regards his products, by virtue of the European

Community directives providing for the affixing of the CE marking.

 

When the CE marking is affixed on a product, it represents a declaration of the

manufacturer or of his authorized representative that the product in question

conforms to all the applicable provisions including the conformity assessment

procedures. This prevents the Member States from limiting the marketing and

putting into service of products bearing the CE marking, unless this measure

is justified by the proved non-conformity of the product.

Flow diagram for the conformity assessment procedures established by the Directive

2006/95/CE on electrical equipment designed for use within particular voltage range:

Manufacturer

Technical file

The manufacturer

draw up the technical

documentation

covering the design,

manufacture and

operation of the

product

EC declaration of

conformity

The manufacturer

guarantees and declares

that his products are in

conformity to the technical

documentation and to the

directive requirements

 

Naval type approval

The environmental conditions which characterize the use of circuit breakers for

on-board installations can be different from the service conditions in standard

industrial environments; as a matter of fact, marine applications can require

installation under particular conditions, such as:

- environments characterized by high temperature and humidity, including saltmist

atmosphere (damp-heat, salt-mist environment);

- on board environments (engine room) where the apparatus operate in the

presence of vibrations characterized by considerable amplitude and duration.

In order to ensure the proper function in such environments, the shipping registers

require that the apparatus has to be tested according to specific type

approval tests, the most significant of which are vibration, dynamic inclination,

humidity and dry-heat tests.

 

 

Standards

“Low Voltage” Directive 2006/95/CE

The Low Voltage Directive refers to any electrical equipment designed for use

at a rated voltage from 50 to 1000 V for alternating current and from 75 to

1500 V for direct current.

In particular, it is applicable to any apparatus used for production, conversion,

transmission, distribution and use of electrical power, such as machines,

transformers, devices, measuring instruments, protection devices and wiring

materials.

The following categories are outside the scope of this Directive:

• electrical equipment for use in an explosive atmosphere;

• electrical equipment for radiology and medical purposes;

• electrical parts for goods and passenger lifts;

• electrical energy meters;

• plugs and socket outlets for domestic use;

• electric fence controllers;

• radio-electrical interference;

• specialized electrical equipment, for use on ships, aircraft or railways, which

complies with the safety provisions drawn up by international bodies in which

the Member States participate.

 

Directive EMC 2004/108/CE (“Electromagnetic Compatibility”)

The Directive on electromagnetic compatibility regards all the electrical and electronic

apparatus as well as systems and installations containing electrical and/

or electronic components. In particular, the apparatus covered by this Directive

are divided into the following categories according to their characteristics:

• domestic radio and TV receivers;

• industrial manufacturing equipment;

• mobile radio equipment;

• mobile radio and commercial radio telephone equipment;

• medical and scientific apparatus;

• information technology equipment (ITE);

• domestic appliances and household electronic equipment;

• aeronautical and marine radio apparatus;

• educational electronic equipment;

• telecommunications networks and apparatus;

• radio and television broadcast transmitters;

• lights and fluorescent lamps.

The apparatus shall be so constructed that:

a) the electromagnetic disturbance it generates does not exceed a level allowing

radio and telecommunications equipment and other apparatus to operate

as intended;

b) the apparatus has an adequate level of intrinsic immunity to electromagnetic

disturbance to enable it to operate as intended.

An apparatus is declared in conformity to the provisions at points a) and b) when

the apparatus complies with the harmonized standards relevant to its product

family or, in case there aren’t any, with the general standards.

ABB MCC