Jouan B4i User manual

CENTRIFUGE
B4i/BR4i
SERVICE MANUAL

CAREFULLY READ THIS MANUAL BEFORE OPERATING YOUR INSTRUMENT.
INFORMATION CONTAINED IN THIS DOCUMENT IS THE PROPERTY OF JOUAN ;
IT MAY NOT BE DUPLICATED OR DISTRIBUTED WITHOUT THE OWNER’S AUTHORIZATION.
CENTRIFUGE
B4i/BR4i
SERVICE MANUAL
89000833-a

B4i-M
REVISION STATUS
INDEX DATE AMENDED PAGES NOTES
a 08/97 Initial release

B4i-M
WARRANTY
Subject to the due observance of any installation, operating or maintenance instructions, we warrant that we will
at our option replace, or repair free of charge, or credit the purchaser with the full invoice price of any goods or
parts of goods of our own manufacture proved to be defective owing to faulty workmanship or materials,
provided that we are notified in writing of the alleged defect within 12 months of the date of despatch of the
goods and the goods are returned to us promptly on discovery of the alleged defect with details of the manner
and circumstances in which they are alleged to have become defective.
Replaced goods become our property.
Goods not manufactured by us are only guaranteed to the guarantee given to us by the actual manufacturers.
Our obligations in respect of defective goods set out above are exclusive and expressly in lieu of all other terms,
warranties and conditions, expressed or implied (including without prejudice to the generality of the foregoing)
warranties and conditions or merchantability and fitness for a particular purpose all of which terms warranties
and conditions are hereby expressly excluded.
It is a condition of sale that the purchaser agrees to keep us indemnified at all times in respect of all actions
proceedings, claims and demands whatsoever which may be made by any third party against us for any loss or
damage howsoever arising (including with prejudice to the generality of the foregoing loss or damage arising
out of the negligence of our employees or agents) which may be caused by goods sold to the purchaser, and all
costs and expenses incurred by us in connection therewith.
All liability for loss of profit, consequential loss, or any other loss whatsoever suffered by the purchaser
howsoever arising (including without prejudice to the generality of the foregoing loss arising out of our
negligence of our servants or agents) is hereby expressly excluded.
In the event that purchaser makes any claims for such or any loss or damage against any of our employees or
agents, it shall pay to us the amount (if any) recovered from such employee or agent and an amount equal to the
legal costs (on a full indemnity basis) incurred by such employee or agent in defending or compromising the
purchaser's claim).

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CHAPTER 1 - INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.1. Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.2. Presentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.3. Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
1.3.1. Dimensions and weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
1.3.2. Electrical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
1.3.3. Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
1.4. Installation procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
CHAPTER 2 - THEORY OF OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2.1. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2.2. Component lay-out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2.3. Motor control principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
2.3.1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
2.3.2. The motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
2.3.3. Power control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
2.4. Electronics - structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
2.4.1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
2.4.2. Microprocessor + power pcb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
2.4.3. Imbalance sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
2.4.4. Tacho sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
2.4.5. Temperature sensor (BR4i) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
2.4.6. Refrigeration control board (BR4i) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
2.4.7. Input - output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11
CHAPTER 3 - DIAGNOSTICS AND REPAIRS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3.1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3.2. Functional test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3.2.1. EPROM version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3.2.2. Test mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3.3. Fault codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
3.4. Troubleshooting chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
CHAPTER 4 - REPLACEMENT PROCEDURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
4.1. Motor replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
4.1.1. Unrefrigerated model (B4i) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
4.1.2. Refrigerated model (BR4i) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
4.2. Imbalance detector replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
4.3. Replacement of the lid lock assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
4.4. Lid lock assembly element replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
4.4.1. Lid lock microswitch replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
4.4.2. Lid lock replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
4.4.3. Lock solenoid microswitch replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
4.4.4. Solenoid replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
4.5. Power supply rack replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
4.5.1. Rack replacement for the B4i. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
4.5.2. Rack replacement for the BR4i. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6
4.5.3. Refrigeration board replacement (BR4i) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6
CONTENTS

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4.6. Electronic board replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7
4.6.1. Microprocessor + power pcb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7
4.6.2. Display board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8
4.7. Keyboard replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8
4.8. Gas spring replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8
4.8.1. Gas spring replacement on the B4i. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8
4.8.2. Gas spring replacement on the BR4i. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9
4.9. Tacho replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9
4.10. EPROM replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10
4.11. Lid replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10
4.12. Refrigeration group repairs (BR4i) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11
4.12.1. Refrigeration group replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11
4.12.2. Condenser components replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12
4.13 Motor checking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12
4.14 Checking and maintenance of the centering group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
CHAPTER 5 - CHECKS, ADJUSTMENTS, CALIBRATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
5.1. Imbalance adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
5.2. Temperature sensor calibration (BR4i) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
CHAPTER 6 - SPARE PARTS - DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.1
6.1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
6.2. Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2
6.3. AUTO-LOCK system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3
6.4. Lock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4
6.5. Feeder group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5
6.6. Refrigeration group (BR4i) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6
6.7. Condenser group (BR4i) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
APPENDIX A - RECOMMENDED LIST OF TOOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1
APPENDIX B - ELECTRICAL DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1

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1.1. PURPOSE
This manual contains maintenance instructions intended for use by a qualified maintenance or service
technician. It is organized to provide maintenance personnel with basic data on the theory of operation to
assist in troubleshooting. Moreover, it outlines parts replacement and calibration procedures for putting
the centrifuges back into service.
Should a specific maintenance problem arise which is not covered in this manual, please ask the
authorized service organization in your area for assistance, or contact our after sales department :
JOUAN SA
AFTER SALES SERVICE
C.P. 3203, 44805 SAINT-HERBLAIN CEDEX - FRANCE
Tel. [phone] - Fax : [phone]
Telex : 711062 JOUAN NT
JOUAN LTD JOUAN GmbH
Merlin Way, Quarry Hill Road Kapellenstrasse 22
ILKESTON, DERBYS, DE7 4RA - U.K. 82008 UNTERHACHING - GERMANY
Tel. [phone] Tel. : [phone]
Fax : [phone] Fax : [phone]
JOUAN INC.
Delivery address : 110-B Industrial Drive, WINCHESTER, VA 22602 - U.S.A
Postal address : P.O. Box 2716, WINCHESTER, VA 22604-9879 - U.S.A
Tel. [phone] - Fax : [phone] - Toll free : [phone]
1.2. PRESENTATION
The B4iand BR4i(refrigerated) centrifuges are instruments designed for laboratory use. Using relative
centrifuge force (RCF) allows elements of different density to be separated.
The rotor is the main load; a swing-out design allows a higher load than does an angle design. The larger
the rotor diameter is, the higher the load can be and thus the slower the speed will be.
The RCF is directly proportional to the radius of sedimentation and to the square of the speed.
The gas used in the refrigeration system (BR4i) is R134a, without CFC, recommended by the directive for
protection of the ozone layer.
1 INTRODUCTION

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1.3. SPECIFICATIONS
1.3.1. DIMENSIONS AND WEIGHT
Dimensions (H x W x D) B4i: 372 x 400 x 495 mm BR4i: 375 x 575 x 605 mm
Packed (H x W x D) B4i: 600 x 610 x 540 mm BR4i: 590 x 720 x 710 mm
Weight - uncrated / crated B4i: 40 kg / 52 kg BR4i: 72 kg / 85 kg
1.3.2. ELECTRICAL SPECIFICATIONS
Mains supply 220/240 VAC 50 Hz B4i: 11175600 BR4i: 11175603
Mains supply 120 VAC 60 Hz B4i: 11175601 BR4i: 11175604
Max power B4i: 500 W BR4i: 800 W
Average power B4i: 350 W BR4i: 550 W
Refrigeration BR4i: 235 W
1.3.3. PERFORMANCE
Max speed Swing-out : 4 000 rpm (B4i) Angle : 14 000 rpm
Swing-out : 4 100 rpm (BR4i)
Max RCF Swing-out : 2 880 x g (B4i) Angle : 18 407 x g
Swing-out : 3 026 x g (BR4i)
Max capacity Swing-out : 4 x 200 ml Angle : 6 x 50 ml
Microprocessor controlled
Display High visibility digital display
Memory size 5 programs, direct access
Program protection Recall key lock
Speed Range 500 to 14 000 rpm
Step 10 -100 rpm
Accuracy ± 20 rpm
Timer Range 30 sec to 99 min + hold position
Step 30 sec to 1 min
Acceleration rates 5
Braking rates 5
Temperature (BR4i) Range -9°C to +40°C
Step 1°C
Accuracy ± 1.5°C
Typical performance 4°C at 4 000 rpm, (4 x 200 ml swing-out)
1°C at 14 000 rpm, (20 x 1.5 ml angle)
Maximum density 1.2 g/cm3
Maximum energy 14 400 J

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1.4. INSTALLATION PROCEDURE
The environment must not be in a dusty room or corrosive environment.
The bench top must be of a rigid construction capable of supporting the weight of the centrifuge.
IMPORTANT : at least two people are required to lift the centrifuge from the palette and place it on the
bench.
WARNING : The rear panel of the instrument must be at least 30 cm from the walls to allows hot air coming
from the condenser to escape.

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2.1. DESCRIPTION
The microprocessor system which controls the B4ior BR4icentrifuges ensures the operation of the
following major elements :
- Management of the operating modes
- Generation of alternating current amplitude and frequency
- Adjustable components for the motor speed servo
- Management of the acceleration and braking profile/rates
- Management of the temperature regulation (BR4i)
- Management of the safety devices :
.Lid lock
.Zero speed detection
.Imbalance detection
.Motor overtemperature detection.
- Management of fault diagnosis.
2.2. COMPONENT LAY-OUT
The inpout and control devices are located on the front panel and comprise a membrane keyboard and
three digital displays.
Everything is controlled by a 16 bit microprocessor. The control program of the centrifuge is stored in an
EPROM.
Data are conveyed into a dynamic RAM and are kept even when the power is down, thanks to an internal
battery, which supplies power.
2 THEORY OF OPERATION

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FIG. 2.1 - BR4i FUNCTIONAL PRESENTATION
FLEXIBLE KEYBOARD
AND DISPLAY
USER
INTERFACE
TEMPERATURE (BR4i)
COMPRESSOR (BR4i)
BOWL (BR4i)
POWER RACK AND
FILTERS
MOTOR SUPPLY
SPEED
IMBALANCE MOTOR
TEMPERATURE
SWITCH
SWITCH
SOLENOID
LOCK ASSEMBLY
CONTROL
SYSTEM

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ROTOR
MOTOR CHAMBER SEAL
LID/BOWL SEAL
MOTOR
STABILIZER
SUSPENSION
IMBALANCE SENSOR
LID
GAS SPRING
LID HINGE
POWER INPUT RACK
CENTRIGUGE BODY
CENTRIFUGE BOWL
LOCKING SYSTEM
COMPRESSOR (BR4i)
FRAME
MOTOR FIXING BOLTS
MICROPROCESSOR + POWER
PCB
DISPLAY ASSEMBLY
FRONT PANEL
KEYBOARD
FIG. 2.2 - BR4i EXPLODED VIEW

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FIG. 2.3 - COMPONENTS OF THE B4i
1. Power supply rack
2. Imbalance sensor
3. Induction motor
4. Centrifugation chamber bowl
5. Lid lock solenoid
6. Display assembly and keyboard
7. Microprocessor/power pcb
8. Gas spring
1. Main socket and fuse carrier
2. Fast-on connection strip
3. Braking resistance
4. DC tranformer
5. Ground/Earth
6. Motor earthing reactor
7. Mains filter
8. Rack
FIG. 2.4 - POWER SUPPLY RACK B4i

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FIG. 2.5 - COMPONENTS OF THE BR4i
1. Cooling fan /condenser
2. Imbalance sensor
3. Induction motor
4. Compressor
5. Lid lock solenoid
6. Display assembly keyboard
7. Microprocessor/power pcb
FIG. 2.6 - POWER SUPPLY RACK BR4i
1. Mains socket
2. Compressor pcb
3. Braking resistances
4. Transformer
5. Ground/ earth
6. Motor earthing reactor
7. Mains filter
8. Rack

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2.3. MOTOR CONTROL PRINCIPLE
2.3.1. INTRODUCTION
The B4i/BR4ifamily of centrifuges is fitted with an asynchronous 3 phase motor. During the centrifugation,
the microprocessor generates a system of sinusoidal 3 phase voltages, variable in amplitude and
frequencies. During the braking phase the energy from the rotating parts is commuted across a resistance.
2.3.2. THE MOTOR
The motor comprises a 3 phase stator and a short-circuited rotor.
When correctly powered, the stator creates a magnetic field rotating at the synchronised speed Ns :
Ns = F/p
F : supply frequency
P : number of pairs of poles of the motor
The rotating field generated in the motor induces e.m.f.'s. These e.m.f.'s produce currents in the short
circuited rotor.
These induced currents found in the magnetic field create forces opposed to those which induced them.
It is the relative speed between the rotor and stator which is the cause of these induced currents, thus the
forces will reduce this relative speed by driving the rotor at a speed close to that of the field created at the
stator.
The difference (s) between the synchronised speed Ns and the actual speed N of the rotor is called the
slippage.
s = Ns - N
Ns
At a given frequency, the slippage value depends on the resisting torque (i.e. that of the rotor).

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The voltage is rectified then filtered by C to supply the constant voltage +E. The value of the capacitor C is
high.
For a 230V - 50 Hz mains supply E = 230 √2 = 325 V
C = 470µF / 400 V
For a 120V - 60 Hz mains supply E = 120 √2 = 170 V
C 1500 µF / 200 V
The 6 transistors act as switches (open or closed).
These transistors commute at a fixed frequency (8 kHz).
To affect the voltage at R we act upon the commands of the transistors a and b, b always being the
opposite to a (a = closed, b = open). By changing the cyclic ratio (closed/open) we obtain a mean
sinusoidal value so we are able to vary the amplitude and frequency.
It is necessary that the pilot frequency must be elevated compared to the frequency of the generated
sinusoidal voltage. The latter is around 400 Hz at 24000 r.p.m. (f pilot / f sin = 10 at N max. speed).
In the same way, the voltages at points S and T will be sinusoidal between OV and +E and dephased by
2π/3 between them.
These 3 voltages are simple voltages varying between OV and +E. They are partly sinusoidal and partly
on a baseline situated at +E/2. Thus the O of the sinusoidal voltage corresponds to 50 % of the cyclic ratio.
The voltages applied to the motor phases are the compound voltages VR-VS, VS-VT,VT-VR and will vary
between + E and - E ([O-(+E) = -E]
Thus at the motor terminals are recreated the voltages whose amplitude is close to that of the mains.
2.3.3. POWER CONTROL
Three voltages, variable in amplitude and frequency, dephased by 2π/3, must be supplied from a 50 or
60 Hz single phase mains supply.
V MAINS
STATOR

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2.4. ELECTRONICS - STRUCTURE
2.4.1. INTRODUCTION
The electronic part of the apparatus is formed of two boards : the microprocessor + power pcb, where
every function is located and the user interface pcb with display and LEDs. The former is located inside the
body of the machine (fig. 2.3 or 2.5, item 7), whereas the second one is in the back of the front panel (fig.
2.3 or 2.5, item 6).
The electronic imbalance sensor is located on the motor stabilizer (fig. 2.3 or 2.5, item 2) and allows the
detection of and excessive imbalance due to the rotor loading.
FIG. 2.7 - VARIATION OF THE CURVE OF THE MOTOR TORQUE AS A FUNCTION OF THE SPEED
C Max
Motor torque
Resistant torque
Torque
Operating point
Speed
Speed synchronisation is directly proportional to the frequency of the voltage supplied to the motor. Ns =
fx 60 (for a 2 pole motor).
The motor rotates at a speed N below the speed Ns.
Ns - N
Ns = SLIPPAGE (the slippage varies between 1 and 3%).
To vary the speed, it is necessary to vary Ns and thus the frequency of the voltage supplied to the motor.
The torque characteristics will be translated on the speed axis. The supply voltage will vary within 0 to
12000 r.p.m. in order to keep the U/f ratio constant and not saturate the magnetic circuit.

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ZONE 1 :
This zone includes the microprocessor, the EPROM containing the software and the non-volatile RAM
containing the program parameters. The set of components in this zone is at the potential of the
microprocessor : 5 VDC.
ZONE 2 :
This zone ensures the conformity of the signal type coming from the different detectors before their arrival
at the microcontroller via opto couplers.
It also monitors the lid lock control and refrigeration group commands.
The power supply for this zone is 12 VDC.
The different signals coming to this zone are :
- Bowl temperature.
- Signal coming from the imbalance sensor
- Tacho signal
- Lid position signal
- The motor overtemperature and the lid lock solenoid control.
2.4.2. MICROPROCESSOR + POWER PCB
On the microprocessor + power pcb, 3 distinct zones can be identified, whose functions are described
below. Each zone has its own independent power supply.

ZONE 3
WARNING ! THIS ZONE IS AT MAINS VOLTAGE
This zone isolated from the microprocessor part by opto-couplers, is the electronic part related to the
power in the system. This zone includes :
-The 15 VDC power supply for the control electronics for this zone.
-The control circuit of the 6 basic signals of the IGBT module.
-The 3 PWR commands coming from the microcontroller
-The brake GBT with the command which permits flow through the braking resistor.-
-The diode bridge which, from the mains, charge the capacitor of the continous bus
-The relay which, controlled by the supply of power, then short circuits the resistance of the charge of the
capacitors of the continuous bus a few moments after switch-on.
-The module of 6 IGBTs and its heat sink which power the motor.
2.4.3.IMBALANCE SENSOR
As described in the introduction, this sensor allows the detection of an excessive imbalance in the rotor
loading.
A piezzo ceramic converts the energy created by the vibration into an electrical signal. After shaping, this
signal is sent to the microprocessor for the safety devices.
2.4.4.TACHO SENSOR
The tacho sensor is comprised of an optical sensor, which, generates two pulses per revolution.
2.4.5.TEMPERATURE SENSOR (BR4i)
After the shaping circuit , the signal is 1.23 Vcc (0°C) ±80 mV/°C
2.4.6.REFRIGERATION CONTROL BOARD (BR4i)
The board controls the power signal to the refrigeration group.
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!

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2.4.7. INPUT - OUTPUT
+12 V
PROBE (°C)
(BR4i)
GROUND/EARTH
IMBALANCE
OPTICAL TACHO
MOTOR OVERTEMP +
SOLENOID SWITCH
230 VAC INPUT
300 VDC BUS
300 V BUS
BRAKING
RESISTOR
MOTOR CONNECTION
24 VAC FOR 15 V REGUL MOTOR CONTROL ZONE
13 VCC OUTPUT FOR REGUL 5 V DISPLAY
9 VAC INPUT FOR 5 V REGUL MICRO ZONE
DISPLAYSKEYBOARD + LEDS
18 VAC
INPUT
LID
SWITCHES
SOLENOID
COMMAND
COOLING
ON/OFF