Eaton Industrial Switchgear - xStart switching, protections and actuating motors

2010

CA08103002Z-EN

www.eaton.com

10/24

Frequency inverters

General information about engineering information

General informationaboutengineering information

Electrical mains connection

M-Max™ and H-Max™ frequency

inverters can be connected and

operated on star-point-grounded

AC mains (according to IEC 60364)

without limitation.

Connection and operation on

asymmetrically grounded networks,

such as phase-grounded delta (USA)

or non-grounded or high-resistance-

grounded (> 30 Ω) IT systems is

permitted with limitations. In these

networks only frequency inverters

without integrated radio interference

suppression filters (EMC) must be

used. On devices with integrated radio

interference suppression filter the

filer’s ground connection must be

disconnected.

The standardized rated operational

voltages of the utility companies fulfil

the following conditions at the point of

transfer to the consumer:

•

Maximum deviation from the rated

voltage (U

±10 %

•

Maximum deviation in the voltage

symmetry: ±3 %

•

Maximum deviation from the rated

frequency: ±4 %

Regarding the lower voltage value

(

-10 %)

of the mains voltage, a

further voltage drop of 4 percent in the

consumer networks is permissible.

The power supply voltage at the

consumer must have a value of

-14 %.

In ring-operated mesh networks

(

such as in the EU) the standardized

consumer voltages (230/400/690 V) are

identical with the utility company’s

supply voltages. In star networks (for

example in North America/USA), the

stated consumer voltages take the

voltage drop from the utility company’s

infeed point to the last consumer into

account.

The wide tolerance band of the

frequency inverters of the M-Max™

and H-Max™ series takes all known

deviations from the standardized rated

operational voltages worldwide into

account (IEC 60038):

230

V: 208 V -15 % - 240 V +10 %

400

V: 380 V -15 % - 480 V +10 %

The permissible frequency range is

Hz -10 % – 60 Hz +10 %.

Safety and switching

The mains-side components are

assigned according to the frequency

inverter’s input-side rated operational

current I

and utilization category

AC-1.

Fuses, circuit-breakers and conductor

cross-sections must meet the national

and regional requirements and the

required approvals at the point of

operation.

For fire prevention and the protection

of persons and domestic animals from

excessive contact voltages residual-

current devices (RCD) must be used.

In combination with a frequency

inverter only AC/DC sensitive RCDs

(

Type B) must be used.

Identification on the residual-

current circuit-breakers

AC/DC sensitive (RCD, type B)

With frequency-controlled power

drive systems (PDS), leakage currents

to ground occur. The main causes are

external capacitances between the

phases of the motor cable, the motor

cable shielding, Y capacitors in the

frequency inverter and radio inter-

ference suppression filters and

grounding measures at the motor’s

site of operation. These leakage

currents can exceed 3.5 mA and

require increased grounding of the

PDS according to EN 50178 (ground

conductor cross-section ≥ 10 mm

EMC measures

Frequency inverters work with fast

electronic switches (IGBT) in the

inverter. This can cause radio inter-

ference in a PDS, which, in turn, can

adversely affect nearby electronic

equipment. To provide protection from

this high-frequency interference,

these should be spatially separated

and shielded from frequency-

controlled PDS.

In Europe, adherence to the EMC

Directive is mandatory. The EMC

product standard for power drive

systems (PDS) is IEC/EN 61800-3. This

standard covers the complete drive

system, from mains infeed to the

motor.

Both versions of the frequency

inverters of theM-Max™and H-Max™

series (with built-in and external radio

interference suppression filter) fulfil

the requirements of the EMC product

standard for residential areas (first

environment), and therefore also for

the higher limit values in industrial

areas (second environment).

PEN

Supply voltage U

of the

utility company

Motor voltage according

to UL 508 C

Consumer voltage, rated

value for the motors

120

110 - 120

115

240

220 - 240

230

480

440 - 480

460

600

550 - 600

575

Frequency inverters

The frequency inverter is an electronic

apparatus for controlling variable-

speed drives with three-phase motors.

It is intended for installation in a

machine or for assembly with other

components to a machine or plant. The

main components of a modern

compact frequency inverter are a

power section and a control section.

Example: M-Max™ series

The frequency inverter’s control

section contains a centrally control-

ling microprocessor, through which all

variable values that occur in the

frequency inverter are influenced.

These values and all control functions

are represented as parameters.

The functional control of the frequency

inverter and the output values in the

power section (such as frequency,

voltage and current) can be adjusted

through:

•

control terminals (I/O) with analog

and digital (binary) inputs,

•

a keypad with function keys and

display,

•

serial interfaces (bus) with RS485

(

Modbus RTU) and optional field bus

connections (CANopen,

PROFIBUS-DP, etc.) and an optional

PC connection.

Internal open and closed-loop control

circuits monitor all variable values in

the frequency inverter and auto-

matically switch the process off if a

quantity value reaches a dangerous

level.

The power section of a static and

compact frequency generally consists

of three subgroups:

•

Rectifier (A),

•

Internal DC link (B),

•

Inverter module (C).

The devices of the H-Max™ series

contain a brake chopper as standard.

Depending on their rating, some

devices of the M-Max™ series also

contain a brake chopper.

Public medium-voltage supply grid

Public

low-voltage supply grid

Industry

grid 1

Industry

grid 2

Measuring

point

Category C1

Category C1/C2

Category C3/C4

st enviroment

nd enviroment

BACK

RESET

LOC

REM

①

Power section

with:

A = Rectifier

B = Internal DC link

C = Inverter module

②

Control section

with:

I/O = analog and binary inputs and

outputs

KEYPAD = keypad with display

BUS = serial interfaces

(

RS485, field bus, PC interface)

= phase voltagefrom

supplying AC mains

= DC link voltage

= 1.41 × U

(

single-phase phase voltage)

= 1.35 × U

(

three-phase phase voltage)

Output voltage =

switched DC link voltage

with sinusoidal pulse-

width modulation

(

PWM)

Block diagram with main components of a frequency inverter

CPU

BUS

KEYPAD

I/O