Category: ABB

Mechanical wear

The number of mechanical operations has a low impact on the life of the main

contacts and their overall electrical life.

However general information concer ning mechanical wear could be of interest.

AC-Hum

Pollution of the magnet pole surfaces will create a slight hum coming from the

contactor in the closed position. When cleaning, use a soft and dry piece of cloth.

Hum can also occur if the pole surfaces are deformed. A louder hum will occur if

the shading coil (does not apply to AF) is broken because the magnet will cause the

contactor to chatter. If so the complete contactor needs to be exchanged.

Another reason for AC-hum could be corrosion caused by environmental conditions that

exceed the contactor specifications.Contactors need to be protected from conden

sation in order to keep the pole surfaces of the magnet free from corrosion.

For more specific information regarding this please see our technical catalog

1SBC1001122C0202. section: General Technical Data.

Guidelines for Contactor inspection and maintenance

Some general advice

1. Choose correctly

• Nature of the duty

• Positioning of the contactor

• Voltage and frequency

• Frequency of operation

• Safety regulations

• Electrical and mechanical stresses

2. Mounting/installation

•  The instructions supplied with every

contactor should be followed.

•  In case of drilling in the panel make sure

to protect the contactor from falling

metal shavings that otherwise could

lead to excessive hum or flashovers.

3. Storage and climate

Consider the immediate environment

(variable temperatures, humidity, storage

conditions etc).

4. Connections

Make sure the recommended torque val

ues given in the instructions are followed

and that proper torque checks depending

on the application are done.

Provided services

Considering the importance of the maintenance activity and

the required technical know-how, ABB guarantees professional

competence. Interventions are performed by ABB recommended

skilled technicians. After the inspection activities, ABB technicians

give all the indications related to the future maintenance needs and

any possible corrective actions, while releasing the final report.

Preventive maintenance program

ABB has designed its maintenance schedule for all contactor

families, based on its technical knowledge of the products and

on its experience in the field.

The preventive maintenance program has the following main targets:

• Check the preservation and the efficiency status of the apparatus

• Anticipate the trend of deterioration of the contactors, signalling

the need for replacement of excessively worn out components,

where available, or suggest alternative solutions for bringing them up to date

• Increase the life cycle of the installation, proposing proactive

maintenance and replacing obsolete components.

Preventive maintenance program

ABB has designed its maintenance schedule for all contactor

families, based on its technical knowledge of the products and

on its experience in the field.

The preventive maintenance program has the following main targets:

• Check the preservation and the efficiency status of the apparatus

• Anticipate the trend of deterioration of the contactors, signalling

the need for replacement of excessively worn out components,

where available, or suggest alternative solutions for bringing them up to date

• Increase the life cycle of the installation, proposing proactive

maintenance and replacing obsolete components.

ABB as leader in design and production for low voltage contactors,

always pays particular attention to customer satisfaction.

Thanks to highly qualified organization, ABB provides support

to customers during all phases of the product’s life cycle, from

product selection to after-sales assistance.

Benefits

Preventive Maintenance creates value over the long-term by

• Providing the best management of maintenance costs, in

particular:– Less expensive direct costs of maintenance, by reducing

the charges due to urgent situations–  Less expensive indirect costs of the installation shut-down,

taking advantage of scheduled stops.

• Ensuring better efficiency and reliability of the equipment

• Extending the contactor’s life

• Guaranteeing the safety of the installation for longer time.

In order to guarantee high levels of efficiency and reliability to

your electrical installation, ABB suggests a regular preventive

maintenance on your installed block contactors.

Preventive maintenance includes the carrying-out of tests,

measurements and any maintenance, repair or replacement

activities, based on specially designed technical plans,

aimed at reducing the probability of failure or the working

deterioration of the apparatus.

Batteries

The accelerating need for mobile energy and protection against

power disturbances in distribution networks is driving the market

of batteries forward. The number of applications where batteries

can  be used is steadily increasing and with that the need of DC

switching. Examples of such applications are charging of vehicle

batteries, DC storage, UPS installations, backup and control

solutions, etc.

Telecom

The telecom industry is today facing a rapid increase of data

transmission which demands larger and more efficient transmis

sion stations. Larger stations may require higher currents and an

increase of voltage in order to reduce energy losses. In this kind

of setup compact, efficient and reliable DC switching is needed.

Special industry:

• DC Drives in e.g. metal refining plants.

Applications

Main applications where contactors are used for DC switching are:

•  Disconnection of the inverter from the PV strings when the

output is too low.

• Changing the string configuration, e.g. to increase plant

efficiency by diverting one or several PV strings to an opti-

mal number of converters at low output. This makes it

possible to constantly optimize the efficiency of the system.

Applications – other

There are several other DC-applications in which ABB’s GAF & AF contactors can be efficiently used.

Traction

Traction vehicles

• Urban traction vehicles such as trams,

subways, commuter trains etc.

• Diesel locomotives

•  Heating applications

Traction wayside

• Signaling

• Switchgear

• Power distribution

What is the future of PV power?

Solar energy is today the fastest growing segment in renewable

energy and is believed to be one of the major energy sources in

the future.

Factors that vouch for a bright future of solar energy:

• Growing climate awareness brings more focus on renewable energy.

• Continuously higher legislative demands on increasing the share of green energy.

• Intense research and development of the PV technology in

order to make it more efficient and easier to produce.

Decreased production costs due to higher volumes and

improved production technique make it possible to pro-

duce low cost PV cells which in turn will expand the market.

Why is DC contactors needed?

PV plants contain some major application for DC swit

ching, since the electricity produced by the PV panels is DC.

Depending on application requirements, different products can

be used for switching. Contactors are typically selected for app

lications with the need for remote control and switching at least

once per day.

The GAF contactor’s ability to break DC up to 2000 A at a voltage

up to 1000 V derives from the use of permanent magnets in the

arc packages. The magnets enable the contactor to extinguish the

powerful electrical arcs that arise between the contact surfaces

when breaking DC. Normal AF contactors can break DC up to

some extent but since they lack the permanent magnets they

will not be able to break DC as a corresponding GAF contactor.

Applications – solar

What is PV power?

Photovoltaic (PV) power is a renewable energy source converting

sunlight directly into electrical energy using PV cells. Large PV

systems often consist of following main components:

• PV cells (combined to strings, generating the power).

•  Inverter (one or several, converting the generated DC voltage

into AC 50Hz or 60Hz, also including devices for switching,

protection and control).

•  Combiners (junction boxes, including switching devices, with

several cables on input and one cable on output).

• Trackers (mechanical structure to move the angle of PV cells

to follow the sun, increasing system efficiency, also including

motors, PLC, communication, protection).

• Switching devices and protection devices (to change PV

string configuration, protect from over currents, surge

voltages and earth faults etc.).

• Distribution transformer (transforming low voltage to high

voltage, as grid connection often is done on high voltage level).

Features and benefits

Powerful

•  1000 V DC switching ratings (IEC).

•  UL (508) rated up to 600 V DC.

Flexible

•  Wide control voltage range (e.g. 100-250 V AC/DC) means

less versions covering the entire range.

•  PLC interface with 24 V DC / 10 mA for GAF/AF400…2050.

•  Ideal for remote and fast operation.

Efficient

•  The AF electronic coil interface reduces power consumption

5-10 times at holding compared to conventional contactors.

Reliable

•  The GAF contactor is based on the well proven AF contactor.

•  Less sensitive to voltage drops due to a drop-out voltage

of 55% of the lower nominal value along with 20 ms sag

and dip immunity. These features avoid the problems with

contactor chattering and welding.

•  Elimination of contact bounce and chattering allows for

increased reliability and service life.

Quiet

•  DC powered coil makes the contactor virtually noise free.

Easy

•  The external dimensions of the GAF contactors are the same

as corresponding AF contactors making it easy to order and install.

•  Existing add on accessories for A/AF range of three pole

contactors will fit the GAF contactors.