Motors For Explosive Atmospheres And Variable Speed Operation; Introduction; Main Requirements According To En And Iec Standards; Winding Insulation - ABB M3JM Betriebsanleitung

6. Motors for explosive atmospheres and variable speed
operation

6.1 Introduction

This part of the manual provides additional instructions for
motors, later Ex motors, used in explosive atmospheres in
a frequency converter supply. Ex motor is intended to
operate from a single frequency converter supply and not
motors running in parallel from one frequency converter. In
addition to these instructions in this manual, additional
instructions provided by the converter manufacturer shall
be followed.
ABB manufactured Ex motors; Ex nA, Ex t, Ex d and Ex de
have been type tested with ACS800/ACS880 converters
in DTC control and ACS550 converters, so these combi-
nations can be selected using the dimensioning instruc-
tions provided in Chapter 6.8.2. The minimum switching
frequency is 3 kHz for all type of Ex motors and is the
basis for the dimensioning guidelines in the following
chapters.
6.2 Main requirements
according to EN and IEC
standards
Flameproof motors Ex d, Ex de
The motor must be dimensioned so that the maximum
surface temperature of the motor is limited according to
the temperature or temperature class. In most cases, this
requires either type tests or controlling the surface
temperature of the motor.
If the temperature class T5 or T6 for Ex d or Ex de motor
is requested, please contact your local sales office for
assistance.
In case of other voltage source converters with pulse width
modulation type of control (PWM), combined tests are
usually needed to confirm the correct thermal performance
of the motor. These tests can be avoided if flameproof
motors are equipped with thermal sensors intended for
control of surface temperatures. Such motors have the
following additional markings on the rating plate: – "PTC"
with the tripping temperature and "DIN 44081/82".
Increased safety motors Ex e
ABB does not recommend the use of random wound low
voltage increased safety motors with variable speed
drives. This manual does not cover these motors in
variable speed drives.
Non-sparking motors Ex nA
The combination of a motor and converter must be tested
as a unit or dimensioned by calculation.
In case of other voltage source PWM converters with a
minimum switching frequency of 3 kHz or higher, prelimi-
nary dimensioning instructions provided in Chapter 6.8.3
in this manual can be used. The final values must be
verified by combined tests.
Dust ignition protection motors, Ex t (Ex tD)
The motor must be dimensioned so that the maximum
outer surface temperature of the motor is limited accord-
ing to the temperature class (e.g. T125 ºC or T150 ºC). For
more information on a temperature class lower than
125 °C, please contact ABB.
In case of other voltage source converters with pulse width
modulation type of control (PWM), combined tests are
usually needed to confirm the correct thermal performance
of the motor. These tests can be avoided if Ex t motors are
equipped with thermal sensors intended for control of the
surface temperatures. Such motors have the following
additional markings on the rating plate: – "PTC" with the
tripping temperature and "DIN 44081/82".
In case of voltage source PWM converters with a minimum
switching frequency of 3 kHz or higher, instructions
provided in Chapter 6.8.3 can be used for preliminary
dimensioning.

6.3 Winding insulation

6.3.1 Phase to phase voltages

The maximum allowed phase to phase voltage peaks on
the motor terminal as a function of the rise time of the
pulse is shown in Figure 5.
The highest curve "ABB Special Insulation" (variant code
405) applies to motors with a special winding insulation for
a frequency converter supply.
The "ABB Standard Insulation" applies to all other motors
covered by this manual.

6.3.2 Phase to ground voltages

The allowed phase to ground voltage peaks at motor
terminals are:
• Standard Insulation 1300 V peak
• Special Insulation 1800 V peak
3GZF500730-47 rev E 06-2015 | ABB Motors and Generators ML/EN – 13