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www.Danoss.com/Drives

The VLT Newsletter

inMotionNo 16, Dec. 2006

Page 1/3New EU standard places more EMC responsibility with users and operators

The revised EMC product standard or

electric drives EN 61800-3: 2005-07 (as o

July 2007) denes new categories C1 to

C4. Depending on the users needs, the

new categories allow extended use o

the existing emission limits in dierent

surroundings. But does this really mean

benets or machine builders, machine

plant operators or end-users o power

drive systems?

The widely used and still applicable EMC

emission standard EN 55011 (conditions:

08/2003) describes the requirements or

each environment by the limit values

ater class B (residential area), or Class

A1 (industrial area). In addition an EMC

standard (EN 61800-3) has been intro-

duced in 1996, which is mandatory or

manuacturers and importers o electri-

cal drives or the CE marking in the EU.

In the rst version o the EN 61800-3 the

limit values or electromagnetic emis-

sion were harmonized with the classes B

and A1 as described in the standard EN

55011.

In addition, relatively high limit values

were allowed in the EN 61800-3 standard

ater class A2 but only or industrial areas

with their own power supply (transorm-

er). This was already violating the har-

monization, since the A2 limits in the EN

55011 were intended only or special ap-

plications with high requencies (no elec-

tric drives). In practice this could result

in sporadic operation ailures, making it

necessary to improve the EMC character-

istics o the equipment later on.

In the meantime a revised version o the

EN 61800-3 took eect and becomes

obligatory in July 2007. In this version,

new EMC categories C1 to C4 are dened

(see table 1), which also reer to the limit

values o the past classes. However this

revised version o the product standard

permits a dierent use in the dierent

environments.

While the category C1 is consistent with

the strict limit values ater EN 55011,

Class B, and thereore is allowed with-

out restrictions or public nets and resi-

New EMC categories forelectric drives are describedin the revised productstandard EN 61800-3.

Dependent on theirinterpretation this mayin the future move theresponsibilities on the sideof the plant and machinebuilders.

New EU standard places more EMC responsibility

with users and operators

By:

Christian Mieslinger, Danfoss Germany

Limits of EN55011 cl. B, A1 and A2


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dential areas (1. Environment), the prod-

uct standard now leaves the decision to

the drives user whether it is appropriate

to engage drives with EMC emissions o

category C2 within this surrounding. The

C2 limit values, however, correspond to

those o the EN 55011, Class A1, which

were, so ar only permissible or industrial

surroundings.

A similar situation is applicable in the

case or installations in industrial environ-

ments.

Here the limit values clearly applies ater

class A1 according to EN 55011 (excep-

tion: voltages > 1000V, rated currents

above 400A or IT network supply).

The operator can now, according to the

new product standard, also decide to

permit drives that only ull the require-

ments o category C3 (corresponding to

EN 55011/class A2).

In both described cases it is mandatory to

place a clear warning in the documenta-

tion to inorm about the increased dan-

ger o EMC disturbance.

At rst sight reduced EMC limit values ap-

pear positive, leading to clearly reduced

screening and ltering measures and by

this reduced installation costs. Also drives

manuacturers in particular could benet

since they possibly could provide prod-

ucts in higher environment classes but

with cheaper EMC lter design.

But by this the decision over, and thus

the responsibility or, employment rests

explicitly on the operator o the machine

and plant. This means, that in case o EMC

problems he has to remove arising unc-

tional problems at his own expense.

Or dierently expressed: the manuactur-

er o the drive system is only responsible

or the adherence to limit values in accor-

dance with the indicated C-category. For

consequences cling only users and opera-

tors.

Since the operator will have dened de-

ault EMC values or individual compo-

nents, the machine builder is however

responsible or the overall unctioning o

his plant. The situation becomes particu-

larly difcult i components come rom

several suppliers.

In such controversies or EMC exami-

nations the limit values are consulted

anyway according to the environment

standard EN55011. Even i the product

standard is kept, other components might

suer rom EMC emissions.

It can be expected that this may become

even worse in uture as more and more

PLC and eldbus unctionalities in mod-

ern controls and drive controllers will also

lead to an increasing number o micropro-

cessors with rising clock requencies. This

inevitably leads to more high requency

intererence sources in the plants.

Category C1 C2 C3 C4

Distribution General

availability

Limited availability Limited

availability

Limited

availability

Environment 1st

environment

1st or 2nd environment

(choice o the user)

2nd

environment

2nd

environment

Supplyvoltage/cur-

rent

< 1000 V > 1000 V,Ir > 400 A or

IT supply

network

EMC

knowledge

No

requirements

Installation and commissioning

by EMC expert only

EMC plan

required

Limitsaccording to

EN 55011

Class B Class A1(+ warning notice)

Class A2(+ warning

notice)

Exceedsvalues

Class A2

EN 55011: 2003

Still validEN 61800-3: 1996

First editionEN 61800-3: 2005-07

Revision valid from 2007

Emissionlimits

Class B

(residential area)

Group 1+2

Environment 1

(residential area)

Class B(1)

Environment 1

(residential area)

Category C1

Class A

(Industrial area)

Group 1

(HF internal)

Environment 2

(Industrial area)

Class A1

Environment 1 or 2

(depending on the decision

of the user)

Category C2

Class A

Group 2

(HF External, not

applicable to drives )

Environment 2

(Industrial area with own supply)

Class A2

Environment 2

(Industrial area)

Category C3

Category C4(Exceeds the Class A2 limits)

Table 1:

C-Categories in the revised EN61800-3

Table 2:

Comparison o the

EMC classes/categories



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Machine suppliers are thereore doing

well to pay good attention in using com-

ponents with good EMC perormance also

in the uture. Within the industrial area

this means limit values ater EN 55011,

Class A1 (corresponding to EN 61800-

3, Category C2) or within the residential

area the limit values ater EN 55011, Class

B (corresponding to EN 61800-3, Cat-

egory C1). Only this way you can be sure

to avoid unctional impairment o other

components and unintended machine

standstill.

Recommended limit values:

Residential area / Environment 1:

EN 61800-3, Category C1

(Limits equivalent to EN 55011 Class B1)

Industrial area / Environment 2:

EN 61800-3, Category C2

(Limits equivalent to EN 55011 Class A1)

Modern electronic drives can, i origi-

nally constructed according to the rules

o electromagnetic noise suppression,

even keep the strict limit values or resi-

dential (private house) areas and or use

o the public net even without additional

external lter components. Such em-

bedded EMC perormance also creates

increased reliability in harsh industrial en-

vironments reducing plant standstill and

related costs.


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