Electric Machinery’s (EM) brushless excitation system provides high reliability through elimination of brushes, collector rings and carbon dust, which in turn greatly reduces inspection and maintenance costs. Rotating rectifier redundancy with detection of diode failure while in operation allows for more convenient maintenance intervals.

• 100% parallel redundant fused diodes are provided to ensure continuous service.

• No exciter outboard bearing is required which eliminates alignment problems associated with three bearing arrangements.

• No carbon dust problems. The exciter operates in the same enclosure as the generator.

• The shaft driven permanent magnet pilot exciter provides a reliable source of exciter field power that eliminates bulky power transformer and

dependence on station battery for field flashing.

• Short circuit sustaining capabilityprovides fault current support.

• No heavy bus work or cable connectionsare required between excitation cubiclesand the generator, thus simplifyinginstallations.

How the brushless exciterprovides generator mainfield excitation.

• Various designs are available to match voltage and current requirements.

• Ability to fit various shaft and mounting configurations.

• No collector rings, brushes or commutators which require maintenance, adjustments and inspections.

Experience

• EM has over a century of design and manufacturing experience, and more than 500 units installed.

• EM is the industry leader in brush- less excitation for 2-pole turbine generators.

• EM brushless exciters are utilized by

generator manufacturers worldwide to meet their brushless requirements.

Brushless Excitation SystemParallel Redundancy for 2-pole Generators70-449kW at 3,000-3,600rpm

WARRANTY

Brushless Excitation System

Parallel Redundancy for 2-pole Generators70-449kW at 3,000-3,600rpm

Converteam Electric Machinery’s (EM) brushless excitation system provides high reliability through elimination of brushes, collector rings and carbon dust, which in turn greatly reduces inspection and maintenance costs. Rotating rectifier redundancy with detection of diode failure while in operation allows for more convenient maintenance intervals.

How the brushless exciter provides generator main field excitation.• Various designs are available to match

voltage and current requirements.

• Ability to fit various shaft and mounting configurations.

• No collector rings, brushes or commutators which require maintenance, adjustments and inspections.

• 100% parallel redundant fused diodes are provided to ensure continuous service.

• No exciter outboard bearing is required which eliminates alignment problems associated with three bearing arrangements.

• No carbon dust problems. The exciter operates in the same enclosure as the generator.

• The shaft driven permanent magnet pilot exciter provides a reliable source of exciter field power that eliminates bulky power transformer and dependence on station battery for field flashing.

• Short circuit sustaining capability provides fault current support.

• No heavy bus work or cable connections are required between excitation cubicles and the generator, thus simplifying installations.

• Large expensive field circuit breaker and field discharge resistor are not required.

• Compact voltage regulator hardware for installation and control panel or switchgear eliminates large excitation cubicles.

Top row (L to R): PMG with armature and rectifiers; Armature with rectifiersBottom row (L to R): Fuse side of diode wheel; Exciter assembly with PMG stator and exciter field

Experience• Converteam EM has over a century of

design and manufacturing experience, and more than 500 units installed.

• Converteam EM is the industry leader in brushless excitation for 2-pole turbine generators.

• Converteam EM brushless exciters are utilized by generator manufacturers worldwide to meet their brushless requirements.

Top row (L to R): PMG with armature and rectifiers; Armature with rectifiers

Bottom row (L to R): Fuse side of diode wheel; Exciter assembly with PMG stator and exciter field

Brushless excitation providesincreased reliability andreduced maintenance costs.

The Permanent Magnet Generator (PMG)supplies high frequency AC power to thevoltage regulator. The voltage regulatorreceives voltage and reactive currentfeedback provided by potential and currenttransformers to provide voltage andreactive current feedback. Comparingthese signals to a reference setpoint in thevoltage regulator, the voltage regulatorprovides a controlled variable DC currentto the stationary field of the rotatingexciter. With its stationary field androtating armature, the exciter generatesthree phase high frequency AC output. Thisoutput is rectified by the rotating rectifiers.This DC current is fed via conductors to thecenter of the rotor shaft and carried by aspecial lead bar in the hollow shaft area

Electric Machinery800 Central Avenue NEMinneapolis, Minnesota 55413United StatesTel: +1 612 378 8000Fax: +1 612 378 8051www.electricmachinery.com

WEG EM Group 2010. Publication NA.10023.gb.06-10.01. WEG EM Group, the WEG EM Group logo and any alternative version thereof are trademarks and service marks of WEG EM Group. The other namesmentioned, registered or not, are the property of their respective companies

WARRANTY

www.converteam.com

Converteam Electric Machinery800 Central Avenue NEMinneapolis, Minnesota 55413United StatesTel: +1 612 378 8000Fax: +1 612 378 8051

North America Headquarters:Converteam Inc.Pittsburgh, PennsylvaniaTel: +1 412 967 0765

France Tel: +33 1 77 31 20 00Germany Tel: +49 30 76 22 0UK Tel: +44 1788 563563Brazil Tel: +55 31 3330 5800China Tel: +86 21 6442 1666India Tel: +91 44 2440 0900Russia Tel: +7 495 225 1916 ©

Con

vert

eam

201

0. P

ublic

atio

n N

A.10

023.

gb.0

6-10

.01.

Con

vert

eam

, the

Con

vert

eam

logo

and

any

alte

rnat

ive

vers

ion

ther

eof a

re tr

adem

arks

and

ser

vice

mar

ks o

f Con

vert

eam

. The

oth

er n

ames

m

entio

ned,

regi

ster

ed o

r not

, are

the

prop

erty

of t

heir

resp

ectiv

e co

mpa

nies

.

Functional diagram of exciter with Permanent Magnet Generator.

ROTATING COMPONENTS

EXCITERFIELD

PMG FIELD(IF FURNISHED)

AUTOMATICVOLTAGE

REGULATORCONTROL PKG

SENSING PT

CCCT

GENERATORFIELD

PERMANENT MAGNETGENERATOR(IF FURNISHED)

STROBELIGHT-FUSE DETECTION(USED WITH FUSEDDIODES ONLY)

STATOR

ROTATINGTRANSMITTERRELAY UNIT

(MOUNTEDIN SWITCHBOARD)

TO ALARM

STATIONARYRECEIVER

FIELD GROUNDDETECTOR

Brushless excitation provides increased reliability and reduced maintenance costs.The Permanent Magnet Generator (PMG) supplies high frequency AC power to the voltage regulator. The voltage regulator receives voltage and reactive current feedback provided by potential and current transformers to provide voltage and reactive current feedback. Comparing these signals to a reference setpoint in the voltage regulator, the voltage regulator provides a controlled variable DC current to the stationary field of the rotating exciter. With its stationary field and rotating armature, the exciter generates three phase high frequency AC output. This output is rectified by the rotating rectifiers. This DC current is fed via conductors to the center of the rotor shaft and carried by a special lead bar in the hollow shaft area under the bearing journal which is then applied to the main generator field winding.

The rotating rectifier is a three phase full wave diode bridge. 100% diode redundancy provides 100% of full rating with a diode out of service.

For parallel redundancy, 100% rated redundant diodes with indicating fuses in series connected in parallel paths permit full load operation even with one diode out of service caused by a failure to a shorted condition. Open fuses are detected during operation by using the strobe light furnished.

Field ground detection is provided without slip rings by means of a transmitter mounted on the diode wheel assembly. A light signal is sent across an airgap to a stationary receiver and relay to indicate presence of a ground.

under the bearing journal which is thenapplied to the main generator field winding.The rotating rectifier is a three phasefull wave diode bridge. 100% dioderedundancy provides 100% of full ratingwith a diode out of service.

For parallel redundancy, 100% ratedredundant diodes with indicating fuses inseries connected in parallel paths permitfull load operation even with one diode outof service caused by a failure to a shortedcondition. Open fuses are detected duringoperation by using the strobe lightfurnished.

Field ground detection is provided withoutslip rings by means of a transmittermounted on the diode wheel assembly.A light signal is sent across an airgap toa stationary receiver and relay to indicatepresence of a ground.