Explosion-Proof Drives
and Marine Applications
for Ships
Safety with explosion-proof drives
for ships and marine applications
The offshore
production platform
"Statfjord B",
equipped with
flameproof threephase motors for
various drives
Liquid gas tanker equipped with explosion-proof three-phase motors
used to drive pumps on the top deck
Drive units in the
aera of the ship in
which there is an
explosion hazard
In areas of ships or offshore units
where there is an explosion hazard,
only specially protected, i.e. explosionproof, motors are used. They must
meet stringent safety criteria and withstand the environmental factors, the
mechanical and electrical loads and
thermal stresses, even under extreme
conditions. In addition to the motors
being of the construction stipulated for
explosion-protected electrical equipment
and complying with the regulations of
the shipping classification societies,
this necessitates adopting special
measures for the IP 56 mechanical
protection system to DIN IEC 34 Part 5,
storage, the cooling system and
corrosion protection.
The three-phase explosion-proof ship´s
motors described here have proven
effective for many years on tankers and
car ferries, in harbour facilities or on
platforms and terminals, even under
extreme conditions. They are used to
drive pumps, compressors, fans, lifts
and lifting gear. They comply with the
regulations of all of the important
classification societies.
SAM Electronics is one of the leading
suppliers of electric motors, especially
explosion-protected designs, for ships
and marine applications. About 100 gas
tankers have been equipped with
electric motors in recent years.
The motors are manufactured in
cooperation with LOHER AG Antriebsysteme under a contractual
arrangement based on the wealth of
experience of the two partners in
building electrical machinery. SAM
Electronics is specialised shipbuilding
know-how means you receive
customised deliveries of high-quality
electric motors tailor-made for shipping.
A highly competent after-sales service
is rounding up the offering.
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Design of the explosion-proof
three-phase motors for gas tankers
Motors with external fans for
mounting on the top deck and
operation at sea
Until a few years ago only electrical
machinery without external fans could
be operated in zones on deck
presenting an explosion hazard. This is
because of the possibility of the cooling
system of a surface-cooled machine
failing, when breakers hit the rotating
fan or ice jams the motor for instance.
On the other hand, since they do not
dissipate as much heat, fanless electric
machines are heavier and take up more
space than surface-cooled motors.
Moreover the rating is limited to a
maximum of 100 kW.
Explosion-proof motors with external
fans are an alternativ. Their specially
designed shaft, fan and fan cooling
allow them to withstand all of the loads
and even flooding in heavy seas.
Flooding test on a
explosion-proof
three-phase motor
on the top deck
Deep-well pump unit
with EEx de IIc T4
three-phase motor
on the top deck of a
liquid gas tanker
Booster pump unit
with EEx de IIC T4
three-phase motor
on the top deck of a
liquid gas tanker
3
Motors without external fans
for mounting on the top deck
and operation at sea
These are low rating designs without
any shaft bushing, fan and fan cooling
at the non-drive end.
Motors with external fans for mounting
on the top deck and operation in port
These motors are only operated in port
for loading and unloading. They differ
from their counterparts for operation at
sea in having an external fan system,
which for this application is equipped
with a rugged fan cowling and a
protective cover in the case of the
IM V1 design.
Deep-well pump unit with EEx de IIC T4 three-phase motor,
mounted on the dome of a tank of a liquid gas tanker
Boat winch drive on the top deck of a
sea-going vessel
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Special design features
The stand models of the salt-waterproof motors have class F insulation.
The mechanical protection system to
DIN IEC 34 Part 5 is IP 56. The motors
have the following protection features:
■ Axial shaft seal in front of the outer
■
■
■
■
shaft bushings; bronze or V2A
running surface for the seals
Spark gap protected against
corrosion, sealing surfaces of the
terminal boxes, centering devices of
the bearing end plates and caps
sealed with salt-water-resistant
grease
On the model with a lubricator the
grease outlet is sealed with a cover
whose slot is filled with grease
All nuts and bolts, shaft grilles for fan
cowlings, cable entries and the name
plate are made of stainless steel
No non-ferrous metal is used for
motor components, such as terminals
or cable entries, for use on ships
with gaseous ammonia
Motors for mounting on the top deck
with increased resistance to chemicals,
salt-laden air and brief flooding are
coated with customised paint systems
providing enhanced corrosion protection.
To protect the stator winding against
wider fluctuations in outside temperatures along with condensation inside
the motor, the motors can be provided
with a standstill heating system.
Special designs, e.g. with brake fitted
or non-return flap at the non-drive end,
are available on request.
Type d AM... three-phase flameproof EEx de
IIC T4 motor
Gas preventing the passage of sparks:
A: Between bearing and plate and stator
frame
B: Between bearing and plate and cap
C: Between lead-through plate and stator
frame
D: Between shaft and bearing cap
E: Between cable bushing and lead-through
plate
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"Flameproof enclosure"
Group II "flameproof enclosure" electrical
machinery is to be designed to comply
with the requirements of European
standards ES 50014, ES 50018 and ES
50019, with a frame that prevents the
passage of sparks, and electrically and
thermally so that the permissible
temperature is not exceeded at any
point on the surface of the frame.
The gaps designed to prevent the passage of sparks (e.g. between bearing
end plate and stator frame, or at the
shaft bushing between bearing cap and
shaft) are of such a size and the
strength of the parts of the frame
chosen so that the frame withstands
the pressure of an explosion of an
inflammable mixture of gases inside
the motor, and prevents transmission
of the explosion to an explosive atmosphere in the surrounding of the frame.
Flameproof motors are generally
equipped with a terminal box providing
"increased safety" (EEx e II) protection.
They are also available with a "flameproof enclosure" (EEx d II) terminal box
on request. Both versions conform to
European standards.
The motors are also supplied with double
protection - "flameproof enclosure"
(EEx d) plus "increased safety" (EEx e II) are also supplied specifically for drives
on liquid gas tankers. The flameproof
enclosure motors with frame preventing
the passage of sparks have the same
electrical and thermal protection features
as their counterparts for "increased
safety".
Processing facility on the top deck of a liquid gas tanker
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Identification system
Electrical equipment must be identified
on its main component. To prevent
confusion this identification system may
only be used for electrical equipment
complying with European standards
EN 50014 to EN 50020.
Explosion protection
Maximum
surface
temperature
of the
equipment
in °C
Tempearture
class
Group
EEx II
Flameproof enclosure
Oil-immersion
Powder-filled
Flange protected enclosure
Increased safety
Intrinsic safety
Electrical
machinery
for hazardous
areas other
than mining
areas with
IIC
risk of
firedamp
Type of
protection
General
symbol
Symbols for explosion protection to EN 50014
d
o
q
p
e
i
for
"e"
II
for
"d"
IIA
IIB
450
300
200
135
100
85
T1
T2
T3
T4
T5
T6
Code examples
Motor in flameproof enclosure
EEx de IIC T4 *
Motor in "increased safety" enclosure
EEx e II T3
Common symbol
*In this example:
d = flameproof enclosure for the motor housing
e = enclosure in "increased safety" for the terminal box
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Printed in Germany · Technical alterations reserved · © SAM Electronics GmbH · DS 1.030.05/2004
SAM Electronics GmbH
Energy and Drives
Behringstrasse 120
22763 Hamburg . Germany
Phone: +49 - (0)40 - 88 25 - 27 06
Fax:
+49 - (0)40 - 88 25 - 41 30
E-mail: [email protected]
www.sam-electronics.de