DC-Motor Description & Maintenance

GPA 654 MDC-MOTORS

DESCRIPTION

DC- motors description 2


Last revision: october 2008

Feed back requisted to:

[email protected]

[email protected]



How a Direct Current motors functions


DC- motors have been used in industrial applications for years.Coupled with a DC-drive, DC motors provide very precise control.DC motor can be used with conveyors, elevators, extruders, marine propulsion, marine applications,….to name a few.

DC- motors are made up of several major components wich include the following:

•Frame

•Shaft

•Bearing

•Main field winding (Stator)

•Armature

•Commutator

•Brush assembly

Of these components, it is important to understand the electrical characteristics of the main field winding, know as the stator, and rotating winding know as the armature. An understanding of these two components will help with the understanding of various function of a DC-drive

(Rotor)

Construction:DC motors


The relation ship of the electrical components of a DC motor is shown in the following illustration. Field winding are mounted on pole pieces to form electromagnets, in smaller DC motor the field may be a permanent magnet. However, in larger DC fields the fields typically an electomagnet. Field winding and pole pieces are bolted to the frame. The armature is supported by bearing and brackets. Carbon brushes are held against the commutator,

The armature rotates between the poles of the field winding. The armatures made up a shaft, core, armature winding, and a commutator. The armature windings are usually form wound and then placed in slots in the core.

BASIC CONSTRUCTION ARMATURE


Brush


Basic DC Motor Operation

Magnetic Fields

A DC motor rotates as a result of two magnetic fields interacting with each other. The first field is the main field that exists in the stator windings. The second field exists in the armature. Whenever is generated around the conductor.


Right-HandRule for Motor

With LAPLACE rule: Armature rotate

Flux + current = rotating force


CEMF Armature Field


Position 3

Commutation


DC-MOTOR YZC 800 DESCRIPTION


YZC800 General description:

This manual is applicable for the marine electric motor YZC800.FL/FWS/FWS-1, which is mainly used for offshore supply-boats. The end-user shall observe the requirement in this manual to ensure the reliable operation of the motor.

All DC-motors are independent field excitation. One is the motor of horizontal-mounted structure (FWS), and the other has a vertical mounted structure (FL). They adopt forced air-cooling and positive explosive-proof lead box . The FL/FW motors are a single shaft extension, which is coupled with drive mechanism through a coupling. The FWS/FWS-1 motors are a double shaft. The motor is fitted with a blower; the cooling air goes inside from the commutator-end and goes outside the pinion end.

Between the commutator-end and lead connecting box, there is the explosive proof pipe installed, the high-pressure can be conducted into the lead connecting box and keep it in positive status.

The motor’s magnet frame is an octagon molded steel plate frame, which is a part of magnetic circuit and also it is the first component of the motor. There are three inspection windows at the commutator-end in order to replace brushes and do maintenance of commutator and brush holder systems. These inspection windows must be closed and proofed when the motor is operating.

Main field coils, commutating-coils and bearings are equipped with temperature sensor. Sensor wiring go into small explosive proof connecting box on frame by lead, on VMS displays end-user can check the temperature of above mentioned parts.

Pressure switches in lead box, in case blower fan wrong, the DC- motor will stop automatically. There is an assistant switch for emergency stop on the side of the lead box in case of necessary. Two 220V, 500W, 60Hz, single-phase heaters fitted at the bottom of commutator end to put through the power

supply when the motor stops operating to avoid the motor being affected by damp .Two G3/8”screw plug at the bottom of commutator end, when water built up inside the motor, open the plug to drain the water.

Changing the current flows through field-armature and field-wingding can control the torque of the motorChanging the current directions flowing through the main field can change rotating direction of the armature. Insulation level of the motor is class H, by using excellent insulation materials and varnishing by vacuum

pressure, it is sure that the motor is in perfect condition of insulation strength, mechanical strength, heat resistance, moisture proof and excellent conduciveness.


trustherPropulsion/FIFI

counterclockwise&clockwiseCLOCKWISEROTATING DIRECTION

FORCED VENTILATION -6600m3/hFORCED VENTILATION -6600m3/hCOOLING

HHINSULATION CLASS ROTOR

HHINSULATION CLASS STATOR

≤ 120V≤ 150VEXCITING maximum VOLTAGE

45A60AMAXIMUM CURRENT EXCITING

85018Nm10055,5 NmMAXIMUM TORQUE

1200 A1600AMAXIMUM CURRENT

-7735NmRATED TORQUE

-1040 tr/mnRATED SPEED

950 A1185 ARATED CURRENT

0 to 600V0 to 750VRATED VOLTAGE

540 KW842 KWRATED POWER

INDEPENDANT EXCITATIONINDEPENDANT EXCITATIONCATEGORY

YZC 800FLYZC 800FL/FWMODEL

YZC 8000FL/FW

HI-TORQUE DC-MOTORS SPECIFICATIONS


Horizontal double shaft.O use YZC800FWS-I

Horizontal double shaftYZC800FWS

Horizontal single shaftYZC800FW

Vertical DC-motorYZC800FL

YZC 800FL

GPA 654 M

YZC 800FL YZC 800FW

YZC 800FWS YZC 800FLYZC 800FWS-1

GPA 254


Blower air Intake

480VAC blower motor

Lead connecting box

Brushes maintenance door

Tº Sensors connecting box

Shaft DC-MOTOR FL


DC-motor with L-drive

Exaust blower flow

Maintenance window With CO2 pipe

Steering gear electric motor

Steering gear hydraulic motor

electric steering Oil pump

Intake blower flow

Sensors Tº connecting box

Note : Caution about vocabulary.

DC- motor is an electric Direct Current motor ( EPD)

L- drive is the kind of propulsion (STEERPROP)


Steerprop:

steering-gear system

Berg: propeler system

L-DRIVE


FRAME

FIELDS

BRUSH HOLDER & BRUSHES Commutator

DC-MOTOR COMPONENTS

ARMATURE WINDIND

SHAFT

DC- MOTOR


FRAME

The motor’s magnet frame is an octagon molded steel plate frame, which is a part of magnetic circuit and also it is the first component of the motor. There are three inspection windows•Support for field•Support for bearings•Support for DC-motor equipment.


Excitating coil unspark paint

FIELD: 8 excitating coils are fixed inside the frame.

4 main coils 2 north poles and 2 south poles create the flux

4 commutator coils for lower the commutation & raise magnetic capacity

Field before painting4 main coils

2 north & 2 souths in opposite position

4 commutator coils

2 north &2 south in opposit position

Main field coil before fitting

commutator field coilbefore fitting

FIELD


To reach brushes and commutator open this door

To reach brushes and commutator open this door

To reach brush-older open thisdoor

BRUSH


COMMUTATOR-END

The commutator is a vital part of every DC motor, it deserve the best os care. The fact that a commutator usually shows signs of distress before trouble actually occurs, is big help to the maintainer. If you can recognize these signs and know what to td, you can often correct the trouble before it becomes serious.

Function

A commutator has three functions:

1) It provides the required sliding electric contact between the fixed brushes and the moving armature to remove or apply electrical energy to the machine.

2) It act as a reversing switch as the ends of the armature coils pass the brush positions the commutator switches them from one circuit to another where the current is flowing in the opposite direction. Thus all the coils have current flowing through them in the proper direction at all time.

3) It also brings to the brush surface the voltage of each armature coil in the circuit. These voltages add up bar between brushes. As a result, the total operating voltage of the machine appears at the brushes


DC. from SCR

DC voltage

0 to 750V

Rotating Force

clockwise

NORTH

SOUTH

With LAPLACE rule Armature turn :

Fluxe + current = rotating force

Right hand rule

Rotating Force

clockwise

Rotating Forces

clockwise

Brushes


4 x 3 BRUSHES

BRUSH- HOLDER

brush caracteristics

T900 carbone/graphite

lents : 900mm

Use size max: 350mm

Cut angle: 50°et 60°

Contact area surface: minimum 80%

BRUSH-SPRING

The quality of the contact between brushes and commutator are paramount to preserve a good functionnality of DC motor.


LEAD CONNECTING BOX

4 positive armature wires

From SCR cabinet

4 negative armature wires

From SCR cabinet

positive connection

negative connection

FIELD connection

sensors connections


YZC 800 FW/FW-1 LEAD CONNECTING BOX

4 positive armature wires

From SCR cabinet

4 negative armature wires

From SCR cabinet

positive connection

Supply + brushes

negative connection

Supply -brushes

FIELD connection

sensors connections


DC-MOTORS ALARMS


All sensor’s paramaters from DC-motors are integrated in Power Management System (technosol)

Parameter DC-motor control


Lock-out DC-motor Air cooling flow sensor DC-motor speed sensor

Temperature winding sensor

two in each coils

Temperature Bearing sensor

One for each Bearing

Greaser for Bearing

YZC800FW/FWS/FWS-1

DC-motor SENSORS


DC-motors temperatures V M S control panel

commutator coils

Main field coils

Bearing

Bearing

Transformer winding


100ºC90ºC110ºCbearing

165ºC155ºC18OºCRΩ=R0(1+a.t)Variation resistance fonctiontemperature

Commutator coil

165ºC155ºC185ºCRΩ=R0(1+a.t)Variation resistance fonctiontemperature

Main field coil

alarmPre-alarmPermissible temperature

rise (C)

Measure method

Parts of motor

Temperatures rated


PRAMETERS DC-MOTOR CONTROL

VMS DISPLAY


DC-MOTORS SCHEMATIC DRAWINGS


FIRING PULSES FROM

SIEMENS SIMOREGDC-DRIVE

45 A

FIELD

CONTACTOR

FIELD

CONTACTOR

Twin reverse speeds contactors for bow thruster

BOW-THRUSTER

Field electric diagram

Φ

B

N

N

N

N

S

S

S

S

AMPMETER

AMPMETER-SHUNT

FUSES

Lead connecting box


Φ

B

FIELD

CONTACTOR

DC-motors & fifi

Field electric diagram

N

S

S

S

S

N

N

N

FIRING PULSES FROM

SIEMENS SIMOREG

FUSES

60 A

AMPMETER

AMPMETER-SHUNT

Bridge rectifier

FIELD

TRANSFORMER 480V/190V


DC-Drives

SCR Bridge

0V To 750V DC

600VAC 480VAC

DC-motors armature supply

TRANSFORMER 3 phases: 2 jobs:

1-increases AC voltage

2-lowers the armonicsDC Drive armature

480ACV

REACTOR 3 phases

- Lower the armomics

DC-Drives propulsion & FIFI

DC-DRIVE

560kW

DC-DRIVE

842kW

AFT & FWD BOW thrusters

0V To 600V DC

460ACV


DC

-MO

TO

RS

MA

INT

EN

AN

CE



General description:

This m

anual is applicable for the marine electric m

otor YZ

C800.F

L/FW

S/F

WS

-1, w

hich is mainly used for offshore drilling transportation boat. T

he end-user shall observe the requirem

ent in this manual to ensure the reliable operation of the m

otor.A

ll DC

-motors are independent field excitation, an advantage to a separately

excited field is the stability of a variable speed to provide independent control of the armature and

field. One is the m

otor of horizontal-mounted structure (F

WS

), and the other has a vertical m

ounted structure (FL). T

hey adopt forced air-cooling and positive volt explosive-proof. The F

L/FW

m

otors are a single shaft extension, which is coupled w

ith drivem

echanism through a coupling.

The F

WS

-1 motors are a double shaft. T

he motor is equipped w

ith a blower; the cooling air goes

inside from the com

mutator end and goes outside the pinion end.

Betw

een the comm

utator end and connection box, there the explosive proof pipe installed, the high-pressure can be conducted into the connection box and keep the connection box in positive status.

The m

otor’s magnet fram

e is an octagon molded steel plate fram

e, which is a part

of magnetic circuit and also is a m

ain component of the m

otor. There are three inspection w

indows

at the comm

utator end in order to replace brushes and do maintenance of com

mutator and brush

holder systems. T

hese inspection window

s must be closed and proofed w

hen the motor is

operating.T

he field coil, comm

utating coil and bearings at both endsare equipped w

ith tem

perature sensor, which go into sm

all explosive proof connection box on frame by lead, in V

MS

displays end-user can know

the temperature of above m

entioned parts. T

here are pressure switches in lead box, once blow

er fan goes wrong, the m

otor will

stop automatically. T

here is an assistant switch for em

ergency stop on the side of the lead box in case of necessary.

Tw

o 220V, 500W

, 60Hz, single-phase heaters fitted at the bottom

of comm

utator end to put through the pow

er supply when the m

otor stops operating to avoid the motor being affected by

damp .T

wo G

3/8”screw plug at the bottom

of comm

utator end, when w

ater built upinside the

motor, open the plug to drain the w

ater.C

hanging the current flows through field arm

ature and fieldw

ingding can control the torque of the m

otor; changing the current directions flowing through thte

main field can change

rotating direction of the armature.

Insulation level of the motor is class H

, by using excellent insulation materials and

varnishing by vacuum

pressure, it is sure that the motor is in perfect condition of insulation strength,

mechanical strength, heat resistance, m

oisture proof and excellent conduciveness.

YZ

C800 F

L: Bow

-thruster


2.1 Clean the shell after sw

itch off the power. T

ear down screen

cover; remove the dust by clean,

dry compressed air. It is necessary to keep interior of the m

otor clean.

NO

TE

: It is forbidden that blow interior of the m

otor with high-pressure air w

hen the motor

electrified. Wear protective clothing, gloves and eye patch to do clean w

ork, and comply w

ith relevant operating instructions.

2.2 Covers should be sm

ooth and complete, be inosculated w

ith the frame, rubber w

asher should be sealed com

pletely, and latches should be fastened.

2.3 clean dust, carbon powder and greasy dirt on insulting arm

of brush holder and Teflon band

with clean, non-cotton cloth to keep the surface clean. G

o over the surface of brush-holder stud, once the crack and burn w

ere found, replace imm

ediately. Check brush leads and clam

p bolts, if the bolts loose, clam

p to proper torque (reference to the torquevalue in part data). C

heck if the spring is flexible or rusted, spring pressure should w

ithin the range of specification. Check if the

brush box is damaged, any dam

aged brush box must be replaced. C

learance between brush box

and comm

utator should be in the range of specification.

NO

TE

: It is not allowed to contact brush holder or

replace brush when the m

otor is operating in order to prevent from

shock hurt.

2.4 Brushed in brush box should m

ove freely, the contacting area between brush and com

mutator

should not less than 80% of brush area; check brush pigtail, it should not be loose, the space

between brush pigtail and com

mutator riser should be kept to avoid scraping each other, m

ake sure the pigtail above the spring.

Brush trade m

ark is T900, m

ixed use of various brush brands are not allowed, because that

may affect the perform

ance of comm

utator. Brushes of one m

otor should be used with sam

e tradem

ark. Change the brushes that have the failure as w

orn to minim

um lim

it or cracked, brush pigtails looseness, color abnorm

ality and so on, note that replace all brushes at one time.

2.5 Com

mutator is a key com

ponent of DC

motor, w

hich should be maintained frequently. Inspect

comm

utator surface regularly, which should have an even and fluster brow

n film covered,

otherwise, the surface shall be repaired.

2.6 Clean poly T

eflon band (located on comm

utator pressing ring) with clean cloth, check if there

is a sign of break-through, makes sure the band w

raps firmly on com

mutator press ring.

2.7 Check if com

mutator riser is w

ell welded. O

nce welding splitis found, repair the ar

mature.

2.8 Check banding tape of arm

ature, if tail of the tape dispersed, loose or any other deterioration is found, then the arm

ature should be repaired.

2.9 Check if there is m

elt solder on steel banding wire at the side of pinion; if their is any solder be

swung to the field coil. R

epair the armature if these happen.

2.10 Wipe dow

n the arcs ring with clean cloth; check if it is d

amaged

by flashover.

2.11 Check appearance of field coil insulation for evidence of overheat.

2.12 Pow

er lead insulation should be well protected, term

inals should be fastened, and ground lead m

ust be firm.

2 Periodical inspection.


SA

FE

TY

RU

LES

before DC

-motors

maintenance operations

1. SC

R breaker in M

.S.B

opened and locked.

3. For blow

use only 8 bars dry air compressed

4. blowing operator should w

ear eyepatch

and durtym

ask.

5. Tools w

ill be secure with a string to enter in the

comm

utator compartim

ent

2. Assistant sw

itch on for DC

-motor em

ergency stop.


RE

PLA

CE

ME

NT

OF

BR

US

HE

S:

Disassem

bly

a. Loose bolts on brushes.b. Lift spring on brushes.c. T

ake out the brushes.d. B

low carbon dust w

ith dry pressure air.

NO

TE

:During operation, the operator should w

ear the protective clothing, glove, and eyeshade and com

ply with the rules.

Assem

bly a. A

ssemble new

brushes; ensure the brushes can move freely in brush

box.b. P

ress spring to the side of new brush carefully, itis incorrect to push

down the spring fast, because it m

ay damage the brush.

NO

TE

:Brushes m

ust be specified; it is not allowed that use brushes in

different types. Replace w

hole set brushes in one motor, or reversing

performance and brush life m

ay be affected. When assem

ble the brushes, brush pigtail should be above the spring, or brush pigtail m

ay be damaged.

c. Screw

down the connection bolts, torque value shallcom

ply with

20±3N,m

ake sure that pigtail above the spring and keep away from

com

mutator surface for a certain distance, can’t be scraped each other.

d. Check spring pressure, w

hich shall comply w

ith 40±4N.

e. Check and screw

down all brush holders connection

f. Rub brushes w

ith glass sand paper, the contact area between

brush and comm

utator should not be less than 80% of brush area.

g. Run the m

otor; inspect operating status of new brushes.

NO

TE

:Em

ery paper is prohibited.


Slide caliper

Max 900m

mM

ini: 550mm

2 bolts

Brushes-H

older

characteristics of brushT

900 carbon/graphitelength : 900m

mU

se size max: 350m

mC

ut angle: 50°et 60°C

ontact area surface: minim

um 80%

3 springs


If the motor appear the failures as follow

s, which should be returned to

manufacturer for repairing w

ithin warranty period, out of the w

arranty period, the m

otor should be returned to manufacture or special plant for

repairing.

a)If m

otor can’t run normally because of com

mutator surface abrasion or burnt.

b) The depth of the slot on com

mutator surface less than 0.9m

m.

c) The m

ica undercutting depth on the comm

utator less than 1mm

.

The depth m

inimum

of the mica

between bars is 1m

m.

Com

mutator m

aintenance:

Keep com

mutator surface clean m

ake. Wipe the surface w

ith a clean cloth with

alcohol if there is oil dust and light burnt mark on com

mutator surface.

If there is obvious burnt mark on com

mutator surface and it can’t be w

iped down by

clean cloth, deal with com

mutator surface w

ith 00# glass emery cloth per follow

ing steps:

NO

TE

:It is forbidden to abrade com

mutator by carborundum

sand cloth,because friction practical m

ay scrap comm

utator surface, and also may adhere in

comm

utator bars and then affect reversing direction. When blow

the motor w

ith pressed air, operator should w

ear protective clothing, gloves and eye patch, and com

ply with the operating instructions


Lead mark of pow

er connection box for the motor

Arm

ature and comm

utator end winding: A

1 A2

Main field w

inding: S

1 S2

A1

A2

S1

S2

Lead box Lead box

Insulation resistance test

Insulating resistance should be tested periodically, measure m

ain field, com

mutator field, arm

ature winding resistance to the ground and insulating

resistance between each other w

ith 1000V m

ega meter, it should not less than

5M

. Hi-pot test applied for 1m

in on every winding and brush holder w

ith50H

Z,

2500V sinusoidal current, should not have the sign of breakdow

n and flashover. H

umidity, dust and carbon pow

der may affect the reading of m

egs measurem

ent, so w

hen the reading is on the low side, cleaning and drying the parts. If the reading is

still low, then the m

otor needs to be disassembled for inspecting.


Lead mark of tem

perature sensor in signal connection box for motor

Main field coil 1 1,2,3,4

Main field coil 2 5,6,7,8

Com

mutator coil 1 9,10,11,12

Com

mutator coil 2 13,14,15,16

Com

mutator end bearing 17,18,19,20

Shaft extension bearing 21,22,23,24

Connect to ground 32

Spare term

inal 25,26,27,28,29,30,31

Pressure sw

itch: 1, 2 normally open (2 and 3 connect perm

anently)

Assistant sw

itch: 3. 4 normally close

Heater : 16.17.18.19

480AC

V blow

er motor 8,9,10

To earth: 20

Spare term

inals: 5.6.7.11.12.13.14.15


Hum

idity, dust and carbon powder m

ay be affecting the reader of megs

measurem

ent, so DC

-motor m

ust be cleaning and drying with air pressure.

the periods during which D

C-m

otors are stopped the heating must be put in

function, thus moisture creates by condensation does not low

er and prevent electric insulation.

Insulating resistance should be tested periodically (see schedule table), with

1000V m

ega meter

-1) m

easure main field, resistance to the ground

-2) com

mutator field, resistance to the ground

It should not less than 5MΩ

.

-3) m

easure resistance between m

ain field & arm

ature.

-4) m

easure the armature resistance value

1,50Ω

-5) m

easure the field resistance value 0,50

Ω

Mega-tester

2Gohm

s.1000V

11 2233 2415

NO

TE

!:Insulation m

easurements above take in count the electric cables supply.

In the event of lower m

easurements than the specifications, insulation m

ust be m

easure again after disconnection of the 10 cables of powers.

If the reading is still low, then, the D

C-

motor needs to be check by E

lectrician specialist or disassem

bled for inspecting.


Arm

ature bearing lubrication

DC

-motors assem

bled without greaser-nose

Arm

ature bearing must be greased before assem

bly. During a period of

overhaul about 2 years, adding grease is not allowed.

At overhauling tim

e, bearings can be cleaned, checked, and greased. Volum

e of lubrication is 1.531kg.

DC

-motors assem

bled with greaser-nose

Bearing

must be to lubricate periodically according to the num

ber operating hour. (see schedule table).

NO

TE

!:S

uper greasing is harmful it involves a too great quantity of grease and of this fact

the bearing enters in overheating quickly.SH

ELL

D6 A

2 G0

FA

GA

RC

AN

OL L135V

BR

AN

DB

earing type grease

Aft bearing

Forw

ard bearing


1300±65(N

.m)

700±36 (N

.m)

340±24 (N

.m)

300±20(N

.m)

155±15(N

.m)

20±3(N

.m)

20±3(N

.m)

20±3(N

.m)

7±1(N

.m)

Fastening

torque (N.m

)

M33

M24

M22

M20

M16

M12

M10

M8

M6

Bolt

diameter

Note:

A bolt

over tightening can damage the filtage

definitively and create a hot spot at the tim

e of the passage of the current.

PE

RIO

DIC

AL IN

SP

EC

TIO

N:

Bolt fasting torque: (N

.m)

6000-R

emove and clean fan blades and housing.

In addition to items 1-2-3

Blow

er4

3000-

Each com

mutator bar m

ust be check and clean with

ethanol and no-cotton cloth(see page 3 m

aintenance manual)

-Check blow

er pressure contactor-T

est emergency contact

-Add bearing grease

In addition to items 1-2

Coils

Field

Com

mutator

brushes

3

1400-B

low out inside connecting box

-check alls terminal connections for tightness

-measure the length and check each brushes

-Test insulation resistance.

In addition to item 1

Control connecting box

2

700B

low out w

ith clean dry compressed air. Inspect

brushes , brush-holders, spring pressure, comm

utator and leads.

Com

mutator B

rushes olderS

pring brush

1

INT

ER

VA

L(hours)

PR

OC

ED

UR

EE

QU

IPE

ME

NT

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DC-Motor Description & Maintenance

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