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Curso de capacitacin GMDRingmotor
ABB University Chile, Noviembre 2012
Contents
Brief history/overview of GMDs Installed base Synchronous motors Insulation systems Ringmotor design
ABB Group November 16, 2012 | Slide 2
Ringmotor design Ringmotor components Ringmotor manufacturing
Fame, laminations, winding, poles, sealing, cooling Instrumentation: Air gap (stationary and rotating), PD
Summary
GMD System overview
T1 T1T1
S
T2
Converter transformer
Cycloconverter & excitation
E-house &
Harmonic filter & power factor compensation
ABB Group November 16, 2012 | Slide 3
SMie
iT
n2
B
A
u+
u-
n1
iR
uR uSuT
iS
i+
i-
3 Ringmotor
excitation Auxiliaries
Controller (drive control, system control)
History, overview of GMDs
In the sixties the cement process started to be controllable, requirements of large cement and raw mills came up
The cement plant Le Havre in France, was the biggest and most advanced cement plant at that time in1969
It was the first straight single line cement plant at that timeSingle cement mill of 160 metric tons / hour was required
ABB Group November 16, 2012 | Slide 4
Single cement mill of 160 metric tons / hour was required No gearbox manufacturer could supply a gearbox for this
size of power BBC (later ABB) came up with the idea of a Gearless Mill Drive
(GMD) of 6400 kW BBC was awarded to supply the first GMD in 1969 Le
Havre/France
History, overview of GMDs (cont.)
The first GMD was running with its original design from 1969 until 2000 and continuous with a new power part (cycloconverter) its operation under full production
Le Havre GMD was controlled by the last generation of mercury rectifiers
Since successfully beginning operation at the end of 1969,
ABB Group November 16, 2012 | Slide 5
Since successfully beginning operation at the end of 1969, this first GMD in the world, operating with a cycloconverter fed synchronous motor, has been followed by much more such drives, firm confirmation that BBC were on the right path
Competition came later into the game when performance data from BBC was visibly very positive
BBC delivered first GMD for the mining industry in 1970 to the Bougainville plant in Papua New Guinea
Recently ordered and installed base
ABB Group November 16, 2012 | Slide 6
Installed Base - Collahuasi, Chile
ABB Group November 16, 2012 | Slide 7
General
No upper design limit to the rated output High power, huge capacity & throughput Drive is constructed with a single motor The air gap can be made sufficiently large This allows the rotor to be mounted directly on the rotating
ABB Group November 16, 2012 | Slide 8
This allows the rotor to be mounted directly on the rotating part of the mill body
Large air gap permits large air gap variations Motor to operate at unit power factor
Basic GMD data
Motor type: Synchronous motor Power range: 528 MW Altitude: 4600 m.a.s.l. Speed range: 015.5 rpm Motor poles: up to 76 poles
ABB Group November 16, 2012 | Slide 9
Motor poles: up to 76 poles Motor torque: up to 28000 kNm Motor frequency: 0 5.8 Hz Motor voltage: 0 5730 V ac Motor current: 0 2500 A Excitation current: 0 700 A dc
Basic GMD data (cont.)
Motor weight: up to 650 tons Pole weight: up to 3 tons Motor height: up to 20 m Motor cooling: air or water cooled Motor air gap: 12.5 22 mm
ABB Group November 16, 2012 | Slide 10
Motor air gap: 12.5 22 mm Motor lifetime: up to 40 years or even more
System advantages
No gear box Minimum number of mechanical components Minimum number of electrical components Only two wearing parts - brushes and dry sealing No inching drive required
ABB Group November 16, 2012 | Slide 11
No inching drive required Variable speed, the base for process optimization Low maintenance
High availability & reliability Bi-directional operation possible
Synchronous motors
Can be used in a very wide range (due to its possibilities of adjustment)
Higher efficiency than induction motors Less voltage drop during start-up Number 2 with respect to number of drives
ABB Group November 16, 2012 | Slide 12
Number 1 with respect to output Its a working horse !
Synchronous motors - fields of application
Compressors (turbo or reciprocating) Pumps Wind tunnels Mills ! Wood grinders
ABB Group November 16, 2012 | Slide 13
Hot rolling mills Hoist drives Excavators Tunnel bore machines T-Bar drive (winter sport) Vertical roller mills And more
Synchronous motors (cont.)
ABB Group November 16, 2012 | Slide 14
Synchronous motors - Turbo-compressor rotor
ABB Group November 16, 2012 | Slide 15
Synchronous motors - Reciprocating compressor rotor
ABB Group November 16, 2012 | Slide 16
Synchronous motors - Mill drive rotor
ABB Group November 16, 2012 | Slide 17
Synchronous motors - components
ABB Group November 16, 2012 | Slide 18
Synchronous motor - basics
Rotational speed n = n0 = f1/p (synchronous speed) Slip s = 0 Stator with 3-phase AC winding DC excitation for rotor winding (excitation current IF)
Either by an external DC generator or by a rectifier
ABB Group November 16, 2012 | Slide 19
Either by an external DC generator or by a rectifier Current to the rotating field windings carried by brushes
and slip rings Alternative: brushless excitation with diode bridge
Synchronous motor basics (cont.)
Cylindrical Motor
ABB Group November 16, 2012 | Slide 20
Salient Pole Motor
Synchronous motor basics (cont.)
ABB Group November 16, 2012 | Slide 21
Synchronous motor basics (cont.)
Cylindrical Typically used for higher speeds (windage losses,
noise) Often 2 pole design, e.g. turbo-generators (50 or 60 Hz)
with 3000 rpm or 3600 rpmLong rotors
ABB Group November 16, 2012 | Slide 22
Long rotors Cylindrical rotor design
Solid rotor (2p = 2 or 4) Laminated rotor (2p 6)
Synchronous motor basics (cont.)
Salient pole Typically used for lower speeds Larger number of poles Single poles feasible due to lower centrifugal forces Large diameter, short axial length
ABB Group November 16, 2012 | Slide 23
Air gap not constant over circumference Salient pole rotor design
Solid poles (with or without damper rings) Laminated poles
With complete damper winding With damper cage Nothing
Synchronous motor Stator core and frame
ABB Group November 16, 2012 | Slide 24
Synchronous motor Salient pole rotor (14P)
ABB Group November 16, 2012 | Slide 25
Synchronous motor Salient pole rotor (4P)
ABB Group November 16, 2012 | Slide 26
Synchronous motor Damper winding
Mechanical or electrical load variations can lead to torque oscillations
This results in torsional vibrations and oscillations in the current
The motor may fall out of synchronizationDamper winding
ABB Group November 16, 2012 | Slide 27
Damper winding Damper winding is similar to cage of induction motor Dampens these oscillations Higher harmonics and resulting losses Used to start synchronous motors similar to induction
motors
Synchronous motor Damper Winding (cont.)
ABB Group November 16, 2012 | Slide 28
Synchronous motor Slip rings on ringmotor
ABB Group November 16, 2012 | Slide 29
Synchronous motor Slip rings on ringmotor (cont.)
ABB Group November 16, 2012 | Slide 30
Synchronous motor Reactive power
Over-excitation Generates reactive power Motor acts as capacitor
Under-excitation Uses reactive power
ABB Group November 16, 2012 | Slide 31
Uses reactive power Motor acts as inductor
Sometimes used as phase shifting element to generate reactive power needed for transformers and induction motors
Synchronous condensor
Synchronous motor Power factor diagram
U1
U
Uh
jXh I1
jX I1
U1
U
.
Uh
jXh I1jX I1
ABB Group November 16, 2012 | Slide 32
Up
.I1
I
jX I1
Up
I1
I
Inductive (Lagging PF) Capacitive (Leading PF)
Synchronous motor Frame of reference
+ q axis- q axis+ d axis
ABB Group November 16, 2012 | Slide 33
- d axis
d: direct axis (in excitation direction) q: quadrature axis (in torque direction)
Synchronous motor Equivalent circuit
ABB Group November 16, 2012 | Slide 34
Quadrature axis (q)Direct axis (d)
Synchronous motor Unbalanced magnetic pull
Depends on magnetic flux (distribution) Occurs when the rotor is eccentric (out of center) Can also occur from magnetic flux asymmetry Force is destabilizing Use of parallel paths in motor stator windings can reduce
ABB Group November 16, 2012 | Slide 35
Use of parallel paths in motor stator windings can reduce UMP effects
Insulation systems
Temperature often the dominating ageing factor Thermal classes (IEC 60085)
Maximum appropriate temperature Class B 130C Class F 155C
ABB Group November 16, 2012 | Slide 36
Class F 155C Other factors of influence
Mechanical stress, vibration, different thermal expansion
Moisture, dirt, chemicals, contaminants
Insulation systems (cont.)
Temperature rise (IEC 60034) Difference of temperature of part and temperature
of coolant Maximum ambient air temperature: 40C Temperature rise is reduced if coolant temperature
exceeds 40C
ABB Group November 16, 2012 | Slide 37
exceeds 40C Class B 85K
Motor winding is only a single turn winding; no interturn failure possible
Temperature rise typically only approximately 50C
GMD Operating parameters
ABB Group November 16, 2012 | Slide 38
GMD - Mill diameters and power (typical)
> 25 feet: typically SAG Mills Pedestal Mounted Ringmotor
15 MW SAG Mills 28 MWMill Cylinder
ABB Group November 16, 2012 | Slide 39
25 feet: typically Ball Mills Foot Mounted Ringmotor
8 MW Ball Mills 22 MW
GMD Mill speed
Critical Speed speed at which the centrifugal
force is big enough that the material sticks to the mill shell and therefore no grinding effect occurs.
ABB Group November 16, 2012 | Slide 40
Mill internal diameter definition depends on the mill supplier:
Shell to Shell Liner to liner
GMD Mill speed on grinding process
ABB Group November 16, 2012 | Slide 41
GMD Mill speed on grinding process (cont.)
SAG Mills: Rated Speed is btw. 74 % and 80 % of Mills Critical Speed Max. Speed is btw. 80 % and 85 % of Mills Critical Speed 8 RPM Rated Speed (RS) 11 RPM (Typical)
Ball Mills Rated Speed is btw. 74 % and 80 % of Mills Critical Speed
ABB Group November 16, 2012 | Slide 42
Rated Speed is btw. 74 % and 80 % of Mills Critical Speed Max. Speed is btw. 80 % and 85 % of Mills Critical Speed 11 RPM Rated Speed (RS) 14 RPM (Typical)
Mill Speeds related parameters 0.3 Hz GMD Operating Frequency 6 Hz Number of Rotor poles
48 to 76 poles (or more) The bigger the Mill diameter the lower the Critical Speed
the higher the number of Rotor Poles
GMD Efficiency, operation
Motors have a high efficiency Less number of poles than other designs Low cooling air flow
Motor is running very soft; no unbalanced torque can be noted (measured with the mill bearing pressure device)
ABB Group November 16, 2012 | Slide 43
Isolation switches for rotor and stator are directly built onto the main terminal box
Only a 3 phase winding in the stator used (no parallel circuits); no uncontrolled torque possible
GMD Mechanical design
Motor is rigid Less deformation of the stator More flexibility for the mill manufacturer
Motor poles can be individually adjusted All torques and forces from rotor to mill flange only by
ABB Group November 16, 2012 | Slide 44
All torques and forces from rotor to mill flange only by friction (no shear forces)
Good access to the liner bolts directly below the motor Advanced sealing system (axial spring loaded dry system) Motor heat exchanger not fixed to the motor housing. No
vibration will be transferred
GMD Ringmotor
Typical SAG Mill design Typical Ball Mill design Manufacturing
Frame Stator core pack
ABB Group November 16, 2012 | Slide 45
Windings Poles and pole fixing Sealing Cooling Instrumentation
Air gap measurement Partial discharge
Pedestal mounted motor
ABB Group November 16, 2012 | Slide 46
Typical SAG mill arrangement
ABB Group November 16, 2012 | Slide 47
Typical SAG mill arrangement (cont.)
ABB Group November 16, 2012 | Slide 48
Antamina SAG mill
ABB Group November 16, 2012 | Slide 49
Century Zinc SAG mill
ABB Group November 16, 2012 | Slide 50
Foot mounted motor
ABB Group November 16, 2012 | Slide 51
Typical Ball mill arrangement
ABB Group November 16, 2012 | Slide 52
Typical Ball mill arrangement (cont.)
ABB Group November 16, 2012 | Slide 53
Antamina Ball Mills
ABB Group November 16, 2012 | Slide 54
Cerro Verde ball mills
ABB Group November 16, 2012 | Slide 55
Cerro Verde ball mills
ABB Group November 16, 2012 | Slide 56
Manufacturing
Stator frame Stator laminations Stator winding Rotor poles Sealing system
ABB Group November 16, 2012 | Slide 57
Sealing system Overpressure fans Cooling circuit Instrumentation
Air gap sensors Partial discharge monitoring
Stator frame
ABB Group November 16, 2012 | Slide 58
Stator frame (cont.)
ABB Group November 16, 2012 | Slide 59
Stator frame (cont.)
ABB Group November 16, 2012 | Slide 60
Stator frame (cont.)
ABB Group November 16, 2012 | Slide 61
Stator frame (cont.)
ABB Group November 16, 2012 | Slide 62
Stator frame (cont.)
ABB Group November 16, 2012 | Slide 63
Stator frame (cont.)
ABB Group November 16, 2012 | Slide 64
Stator frame (cont.)
ABB Group November 16, 2012 | Slide 65
Stator frame (cont.)
ABB Group November 16, 2012 | Slide 66
Stator laminations
ABB Group November 16, 2012 | Slide 67
Stator lamination stacking
ABB Group November 16, 2012 | Slide 68
Stator lamination stacking (cont.)
First lamination 2 mm carbon steel plate
Remaining laminations 0.5 mm non grain orientated silicon steel
ABB Group November 16, 2012 | Slide 69
Stator lamination stacking (cont.)
First package of laminations glued together with resin
Same resin as the windings, slightly diluted to reduce viscosity
ABB Group November 16, 2012 | Slide 70
Stator lamination stacking (cont.)
Keybars, hanging plates and first set of laminations.
ABB Group November 16, 2012 | Slide 71
Stator lamination stacking (cont.)
Lamination being stacked.
ABB Group November 16, 2012 | Slide 72
Lamination at stator partition.
Stator lamination stacking (cont.)
ABB Group November 16, 2012 | Slide 73
Stator lamination pressing
ABB Group November 16, 2012 | Slide 74
Stator lamination pressing (cont.)
ABB Group November 16, 2012 | Slide 75
Stator winding - Slot fill
Upper Wedge
Ripple Spring
Lower wedge, packer
Main insulation with
ABB Group November 16, 2012 | Slide 76
Main insulation with
Outer corona protection
Separator or RTD
Round Packing
Inner corona protection(if necessary)
Stator winding Automatic taping
ABB Group November 16, 2012 | Slide 77
Stator winding - Bars
ABB Group November 16, 2012 | Slide 78
Stator winding Bars ready for insertion
ABB Group November 16, 2012 | Slide 79
Stator winding - Stator bar insertion
ABB Group November 16, 2012 | Slide 80
Stator winding - Wedging
ABB Group November 16, 2012 | Slide 81
Stator winding End connections
ABB Group November 16, 2012 | Slide 82
Stator winding End connections (cont.)
ABB Group November 16, 2012 | Slide 83
Stator winding End connections (cont.)
ABB Group November 16, 2012 | Slide 84
Stator winding - Stator terminals
ABB Group November 16, 2012 | Slide 85
Rotor Pole
ABB Group November 16, 2012 | Slide 86
Rotor Pole (cont.)
ABB Group November 16, 2012 | Slide 87
Pole mounting
ABB Group November 16, 2012 | Slide 88
Pole mounting (cont.)
ABB Group November 16, 2012 | Slide 89
Rotor pole
ABB Group November 16, 2012 | Slide 90
Rotor pole arrangement
ABB Group November 16, 2012 | Slide 91
Rotor pole arrangement (cont.)
Slip rings
ABB Group November 16, 2012 | Slide 92
Face forteflon seal
Rotor cover
Central fixation bolt
Mill flange Eccentric bushings
Lateralfixation bolt
Pole central plate
Rotor cover
Rotor pole arrangement (cont.)
Slip rings
ABB Group November 16, 2012 | Slide 93
Face forteflon seal
Rotor cover
Pole bolt with eccentric bushing
Mill flange
Central fixation bolt
Rotor pole - Manufacturing
ABB Group November 16, 2012 | Slide 94
Rotor pole - Pole units prior to impregnation
ABB Group November 16, 2012 | Slide 95
Sealing system
ABB Group November 16, 2012 | Slide 96
Sealing system (cont.)
Stator cover
Inside motor
ABB Group November 16, 2012 | Slide 97
Rotor cover Spring
Mechanicalprotection
Rubber seal
Sealing lip
Sealing lip
Teflon spacers
Inside mill
Inside motor
Sealing system (cont.)
ABB Group November 16, 2012 | Slide 98
Sealing system: Over-pressure fans
ABB Group November 16, 2012 | Slide 99
Sealing system: Over-pressure fans
2 fans with ~2 kW each To generate over-pressure
inside the motor Typical values:
400 Pa static pressure 1 m3/s air flow
ABB Group November 16, 2012 | Slide 100
1 m3/s air flow At site altitude
Keep dust out of the motor Symmetric design Filter cartridge
1 10 m Water resistant
Sealing system: Type 3 filter cartridge
ABB Group November 16, 2012 | Slide 101
Sealing system: Type 3 filter cartridge
ABB Group November 16, 2012 | Slide 102
Motor cooling
ABB Group November 16, 2012 | Slide 103
Motor general cooling arrangement
Air to water
Fan
Air
ABB Group November 16, 2012 | Slide 104
ACMotor
Air
Heat Exchanger
Water
Motor general cooling arrangement (cont.)
Air to Water Air
Fan
Air
Fan
ABB Group November 16, 2012 | Slide 105
Air
Heat Exchanger
ACMotor
Motor general cooling arrangement (cont.)
Air to Water to Air
FanFan
AirAir
ABB Group November 16, 2012 | Slide 106
Heat Exchanger Heat Exchanger
Air
WaterAC
Motor
Motor cooling systems: Chillers
ABB Group November 16, 2012 | Slide 107
Ringmotor instrumentation Stationary air gap sensors
Terminal Box
ABB Group November 16, 2012 | Slide 108
Terminal Box
Stationary air gap sensors (cont.)
3 static sensors Redundancy Alarm- and trip levels of the
air gap Normal operation
ABB Group November 16, 2012 | Slide 109
16 mm, rotor centered Alarm
Out of center by 4 mm Trip
Out of center by 5 mm
Stationary air gap sensors - conditioner box
ABB Group November 16, 2012 | Slide 110
Stationary air gap sensors - Air gap measurement
Measuring method: Contactless, capacitive
Scale range: 0,5 - 100 mm (depending on
probe dimensions) Accuracy:
ABB Group November 16, 2012 | Slide 111
Accuracy: 2% approx.
Temperature range: 0C ....... +125C
Probe: 120 x 90 x 2 mm
Meter amplifier: 190 x 120 x 60 mm
Ringmotor instrumentation - Rotating air gap measurement
ABB Group November 16, 2012 | Slide 112
Rotating air gap measurement (cont.)
Rotating sensor installed on a rotor pole, e.g. Pole # 1. Same sensor type as static system Transmitter and antenna installed on rotor cover Power for transmitter supplied from rotor poles suitably
transformed and protected.
ABB Group November 16, 2012 | Slide 113
Digital signal transfer between transmitter and receiver Frequency 2.4 GHz Receiver installed outside stator frame . As close to line of
sight installation for optimum signal. Key phasor (proximity sensor) installed on motor to
develop actual rotor pole position.
Rotating air gap measurement - Transmitter
ABB Group November 16, 2012 | Slide 114
Rotating air gap measurement Probe and Conditioner
ABB Group November 16, 2012 | Slide 115
Rotating air gap measurement Antenna
ABB Group November 16, 2012 | Slide 116
Rotating air gap measurement - Visualisation
ABB Group November 16, 2012 | Slide 117
Rotating air gap measurement Visualisation (cont.)
ABB Group November 16, 2012 | Slide 118
Instrumentation - Partial Discharge (PD) Monitoring
During operation the insulation system of any electric motor is subjected to a number of stresses.
On-line partial discharge allows PD activity to be recorded whilst the GMD is subjected to normal operating stresses:
Thermal winding temperature, thermal cycling, etc
Electrical grid over-voltage, discharges in voids, etc.
ABB Group November 16, 2012 | Slide 119
Ambient humidity, oil, carbon dust, etc.Mechanical vibrations, electromagnetic forces, etc.
On-line partial discharge is an additional measurement tool to assess the integrity of the insulation of the GMD without having to shut the GMD down.
Important terms: On-line versus off-line Continuous versus time interval measurements
PD possible areas of discharge
ABB Group November 16, 2012 | Slide 120
PD - Mechanisms
PD is a local breakdown phenomenon of microscopic voids causing small sparks.
PD produce high frequency signals as a superposition to the line voltage.
The high frequency signals can be measured by installing couplers.
ABB Group November 16, 2012 | Slide 121
couplers. Patterns gained from measurements allow identification
and localization of insulation defects and upcoming failures.
Over time PD has an ageing effect on the insulation.
PD - Typical schematic
ABB Group November 16, 2012 | Slide 122
PD - Components
One per phase, one in neutral for noise filteringType CC7, 1000 pFIEC 60034-27 gives guidelines for value of coupling capacitor capacitance to be at least 1000 pF.Allows safe and consistent hook-up point for measurement.
ABB Group November 16, 2012 | Slide 123
measurement.
Surge protected to 90 V
IP65 enclosureClosed during normal mill operation
MICAMAXX pdplus portable measurement deviceUse for all installations
On-line PD measurements
Takes 30 seconds per phase measurement Accomplished in approximately two minutes Ringmotor is RUNNING (on-line measurement)
Thermal equilibrium (constant full load) Rated Voltage
ABB Group November 16, 2012 | Slide 124
Rated Voltage Rated Speed Measured humidity Measured winding temperature Measured current/load and voltage Allows for subsequent measurement comparisons
PD - Typical report information
ABB Group November 16, 2012 | Slide 125
PD - Typical report (cont.)
Specific report per measurement instance. PD measurement is a trending tool. Can compare subsequent measurements and be able to
advise future of the insulation. Can advise suitable preventative maintenance measures,
e.g. clean the end winding from contamination.
ABB Group November 16, 2012 | Slide 126
e.g. clean the end winding from contamination. Made more valuable when coupled with additional
measurement methods.
Summary, recap
Brief history/overview of GMDs Installed base Synchronous motors Insulation systems Ringmotor design
ABB Group November 16, 2012 | Slide 127
Ringmotor design Ringmotor components Ringmotor manufacturing
Fame, laminations, winding, poles, sealing, cooling Instrumentation: Air gap (stationary and rotating), PD
ABB Group November 16, 2012 | Slide 128