Frequency Converter
Logic
Out
Control Card
Potentially explosive
atmosphere
PTC-Sensors
3~ Ex-Motor
Saf
e
Channel T37
Safe Stop
T37
T1
TP
TP
T2
+24 V
PTC Thermistor Card
MCB 112
Non-explosive hazard zone
91
92
93
96
97
98
Converter module
130BE102.10
DI
Illustration 1.2 Block Diagram of the System
1.6 Motor Requirements
1.6.1 Motor Limits and Rules
For every certified motor with increased safety, the
manufacturer supplies a data list including limits and rules.
During planning, installation, commissioning, operation,
and service, respect the limits for:
•
Minimum switching frequency.
•
Maximum current.
•
Minimum motor frequency.
•
Maximum motor frequency.
Furthermore, respect the following:
•
Do not exceed the maximum allowable ratio
between frequency converter size and motor size.
The typical value is
I
VLT, n
≤
2x
I
m,n
.
•
Consider all voltage drops from the frequency
converter to the motor. If the motor is running
with lower voltage than listed in the U/f charac-
teristics, current might increase and cause an
alarm.
•
Multi-motor applications are not allowed. Only
connect 1 motor to the frequency converter.
1.6.2 Additional Motor Requirements
The Ex-e motor must be approved for operation in
hazardous zones (ATEX Zone 1/21, ATEX Zone 2/22) in
combination with frequency converters. The motor must
be certified for the particular hazardous zone.
The Ex-n motor must be approved for operation in
hazardous zones (ATEX Zone 2/22) in combination with
frequency conveters. The motor must be certified for the
particular harzardous zone.
NOTICE
The motor can be placed in Zone 1/21 or 2/22 according
to motor approval. The frequency converter must always
be installed outside of the hazardous zone.
•
Only operate explosion-protected 3-phase motors
with frequency converters, if the motors are built,
tested, approved, and labelled separately for this
mode.
•
When the usage of the motor and its thermal
protective device are approved for frequency
converter operation, use the MCB 112 for each
ignition protection system for all motor types. For
motors of Ex-e and Ex-n-type ignition protection,
which are OEM-approved for frequency converter
operation in Ex-harzardous areas, consider and
use the requested limitations in the frequency
converter’s ATEX ETR thermal monitoring settings.
•
The necessary parameters and conditions can be
found on the nameplate or the documentation of
the motor. To prevent prohibited temperatures,
the motors are equipped as standard with
thermal winding protection, which has to be
evaluated by a suitable device like MCB 112. The
motors must not be operated as a group drive.
1.7 Approvals and Certifications
Certification number:
PTB 14 ATEX 3012U
Certificates and declarations of conformity are available.
Contact a local Danfoss partner.
Introduction
Operating Instructions
MG33V302
Danfoss A/S © 01/2015 All rights reserved.
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