Philips Optimus 50, Optimus 65, Optimus 80 Operation Manual

4512 984 22721 REV AB

0.5

UNIT_ConvTestKit_div05_22721_AB

FILING INSTRUCTIONS

File this documentation in binder:

SUBSYSTEM manual OPTIMUS

Converter test kit OPTIMUS

for OPTIMUS 50/65/80 generators Release 3.x

with converters 4512 104 7231 1/2/3

4512 104 91681

Converter test kit

742

4512 984 22721 REV AB

H

Philips Medical Systems DMC GmbH

SERVICE MANUAL 742 UNIT

Converter test kit OPTIMUS

for OPTIMUS 50/65/80 generators Release 3.x

with converters 4512 104 7231 1/2/3

4512 104 91681

Printed in Hamburg, Germany

4512 984 22721 REV AB 1

DMC Hamburg

OPTIMUS CONVERTER TEST KIT

SERVICE MANUAL - UNIT

Converter test kit OPTIMUS for OPTIMUS 50/65/80 generators Release 3.x

Author: A. Duve

with converters 4512 104 7231 1/2/3

Type No: 4512 104 91681

In case there are any questions concerning this manual, please send this LOPAD via fax to 49/(0)40/5078 2481

File: UNIT_ConvTestKit_22721_AB_BW.doc

List of pages and drawings (LOPAD) Manual Order No: 4512 984 22721 released 11/2002

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1 2

3...39 (02.0)

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6-01 (b/02.0) OPTIMUS RF

6-1 ... 6-24 (b/02.0) OPTIMUS RF

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CONVERTER TEST KIT OPTIMUS

TEXT

Contents .......................................................................................5

Introduction.................................................................................. 5

1.

1.1. Scope of delivery ............................................................................................ 5

1.2. Tools...............................................................................................................5

2. Generator condition after failure event .....................................6

2.1. Special case ...................................................................................................6

2.2. All other cases ................................................................................................6

2.3. Prerequisites before checking the generator ..................................................6

3. Check of generator mains supply parts .................................... 7

3.1. Condition(s) when the service comes to the site ............................................8

3.1.1. ENF2 tripped, possibly in combination with ENF1 and? mains fuses...................................... 8

3.1.2. ENF1 tripped, possibly in combination with mains fuses ......................................................... 8

3.2. Check for open springs at damping resistors.................................................. 9

3.3. Check for contacts that are welded at breakers and contactors ..................... 9

4. Converter checks (EQ frontal and E2Q rear)...........................10

4.1. Visual converter check..................................................................................10

4.2. Measuring of converter parts ........................................................................10

4.2.1. Rectifier check........................................................................................................................ 10

4.2.2. IGBT check............................................................................................................................. 11

4.2.3. Overvoltage diode check........................................................................................................ 12

4.2.4. Resistor check (PCB versions 4512 108 0862x / 0934x)....................................................... 12

4.2.5. Power cable harness check ................................................................................................... 13

4.2.6. Resonance capacitor check ................................................................................................... 13

5. Check of the high voltage transformer....................................14

5.1. Analysis ........................................................................................................15

6. Visual check of the X-ray tube.................................................. 16

7. Interim results ............................................................................ 16

8. Tube check with Rotor Control part 1.....................................17

9. kV-driver test.............................................................................. 17

10. Tube check with Rotor Control part 2.....................................18

11. Tube and high-voltage cable test with high voltage............... 19

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12. Measuring of primary currents................................................. 23

12.1. Measuring of the resonance frequency.........................................................28

12.2. Measurement of kV behavior with an adapted tube...................................... 29

12.3. Measuring of kV behavior with a non-adapted tube (Optimus 65/80) ........... 30

13. Reconditioning of the tube(s)................................................... 31

14. Final system test........................................................................ 33

APPENDIX

List of checked parts of generator 3x...................................... 37

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1. Introduction

With this document it should be possible to determine which part of kV units of an Optimus generator is still operational and which part is defective and has to be replaced.

1.1. Scope of delivery

- 2 current transformers (ratio 1:1000, 20Ω resistors at the secondary coil give a ratio of 50A primary / 1V secondary)

- Test cable with resistor

- Test cable with diode

- Unit Manual Converter R/F

- This documentation

1.2. Tools

- Standard tools

- Extension boards C (96-pin)

- Dual trace oscilloscope with:

- 2 probes for signals

- 1 probe for external triggering

- Multimeter with diode test option

- 1 battery 1.5V D cell (R20) preferred C cell (R14) or AA cell (R6) possible

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2. Generator condition after failure event

ENF1 and/or ENF2 and/or ENF3 tripped.

Mains fuses might have additionally tripped.

2.1. Special case

ENF3 tripped, possibly in combination with ENF2 and? ENF1 and? mains fuses:

Problem most likely caused by rotor control unit EY (high speed) or EYA (low speed). Solutions for rotor control problems are not part of this document.

2.2. All other cases

The generator has to be kept in this condition to discover the cause of the problem.

A non-qualified person (e.g. hospital technician not familiar with Optimus) should not be asked to just turn the fuses back on to prevent further damage.

A qualified person like a Philips field engineer (trained on Optimus) must visit the site.

2.3. Prerequisites before checking the generator

CAUTION!

Do not remove PCB kV-power from the IGBT transistors. Electrostatic discharge and mobile phone waves can damage and destroy IGBTs when gate connections are open.

WARNING!

The generator must be switched OFF and must be completely cut from mains (e.g. room mains switch or earth leakage current breaker).

All following checks must be made without mains power.

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3. Check of generator mains supply parts

• Measure DC voltage at auxiliary contacts 41-42 of ENK2. (Converter DC discharging contact, max voltage can be 750VDC.)

If 0V is measured:

-

the contact is closed (and the converter DC is discharged within 1 minute)

or

- the contact is open and the converter DC is discharged and safe.

WARNING!

In case one of the ENK2 main contacts is welded the converter DC discharge time is much longer as the discharging auxiliary contact ENK2 41-42 cannot be closed.

600VDC discharge time to < 60VDC normally With open contact

> 11 minutes

to be < 60VDC.

40 seconds.

• Check if any main contact of contactor ENK2 is welded:

Mechanical check: If snap-on auxiliary contacts or auxiliary contact block cannot be removed from the main

contactor at least one contact is welded.

ENK2 phase 1 1 - 2 contactor ENK2 2422 132 06621 phase 2 3 - 4 + 3 aux. contacts NO 2422 135 04355 phase 3 5 - 6 + 1 aux. contact NC 2422 135 04023

or

successor contactor 2422 132 07381 + succ. aux. cont. block 2422 135 04464

+ succ. R/C circuit 2422 135 04661

• Record the conditions on last page.

• If contacts have been found to be welded replace contactor, its auxiliary contacts or contact block

+ the R/C circuit.

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3.1. Condition(s) when the service comes to the site

3.1.1. ENF2 tripped, possibly in combination with ENF1 and? mains fuses

Problem might be caused by any of the:

- internal generator units (Optimus RAD + R/F)

or

- external units (Optimus RAD only) connected to breaker ENF2 :T1 :T2 :T3.

Solutions for such a case are not part of this document.

3.1.2. ENF1 tripped, possibly in combination with mains fuses

Problem most likely caused by kV unit malfunction (kV-control, kV-power, converter(s), HV transformer) or external parts e.g. HV cable(s) or tube.

• Open the cover of the frontal (and rear where present) converter.

• Measure DC at PCB kV-power EQ100 at E2 – C1 (at both converters, see layout drawings attached).

The measured DC must be < 10VDC.

WARNING!

Make sure that the DC voltage in the converter is discharged.

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3.2. Check for open springs at damping resistors

EN :R1 safety resistor 47Ω 100W 4512 100 45441

:R2 :R3

• Record the conditions on sheet of appendix.

• Check for open springs at damping resistors.

Springs might be open if all breakers are ON when the service comes to the site. In this case the generator must have been switched ON after all fuses and breakers were reactivated. Shortcircuit in the converter or its mains rectifier/filter could have happened. Springs can be resoldered. If the springs have to be resoldered, use as little solder as possible.

• Check that the ceramic resistor bodies do not have cracks. In case of cracks the springs must be resoldered.

3.3. Check for contacts that are welded at breakers and contactors

• Switch OFF breakers ENF1 and ENF2.

ENF1 L1 – T1 automatic circuit-breaker ENF1 Optimus 50 2422 129 15514 L2 – T2 or successor 2422 129 16291 L3 – T3 Optimus 65/80 2422 129 15513

or successor 2422 129 16292

ENF2 L1 – T1 automatic circuit-breaker ENF2 Optimus 50/65/80 2412 129 00341 L2 – T2 or successor 2422 129 16288 L3 – T3

ENK1 phase 1 2 – 1 contactor ENK1 Optimus 50 2422 132 06625 phase 2 4 – 3 or successor 2422 132 07382 phase 3 6 – 5 + R/C circuit 2422 135 04662

Optimus 65/80 2422 132 06624 or successor 2422 132 07383 + R/C circuit 2422 135 04662

• Record the conditions of the breakers in the appendix.

• Check for contacts that are welded at breakers and contactors.

If contacts have been found to be welded replace breaker(s) and/or contactor(s).

• Remove the converter mains lines (frontal and rear converter) from contactor ENK1 :1 :3 :5. Measure with an ohmmeter each line against the others (of each converter). There should be no short-circuit, the meter should display 2MΩ ±5% after at least 20 seconds (filter resistors).

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OPTIMUS CONVERTER TEST KIT

4. Converter checks (EQ frontal and E2Q rear)

4.1. Visual converter check

• Check the converter visually. The entire converter chassis must be replaced if cracks are visible at the white IGBT body (looking through the converter cage grid) or if the kV-power PCB Q100 is bent towards the cover plate.

4.2. Measuring of converter parts

Use an ohmmeter which has a diode test feature.

• Check the polarity of the meter (for ohm and diode testing):

Anode of diode symbol on meter = positive voltage >>

Cathode of diode symbol on meter = negative voltage >>

Ω

= Normal ohm measurements

➙

= Diode test option of meter

4.2.1. Rectifier check

• Open the right side of the converter(s) to get access to the mains rectifier.

L1 ⊘ ⊘ –

L2 ⊘ ⊘ –

L3 ⊘ ⊘ +

MINUS PLUS ➙ PLUS MINUS ➙

L1 / L2 / L3 ⊘ ⊘ – ⊘ + L1 / L2 / L3 ⊘ ⊘ – ⊘ +

450mV ±10%

• Record the conditions in the appendix.

Rectifier EQV5 layout

∞

PLUS

MINUS

(see measurement)

(tables)

∞

450mV ±10%

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4.2.2. IGBT check

Legend

typical values when part is OK

typical values of defective parts

If at least one test fails the converter must be exchanged.

Proceed with chapter 5.

The table below shows results of IGBT emitter - collector measurement. Converter working OK and completely assembled. Q100 kV-power PCB 4512 108 0862x / 0934x

MINUS PLUS

E1

E2,3,4

C1

C2,3,4

Ω

21.5 - 22kΩ

➙

∞

PLUS MINUS

E1

E2,3,4

C1

C2,3,4

Ω

16.5kΩ ±10%

➙

300mV ±10%

Ex Cx

0 Ω

< 200mV

Ex Cx

The table below shows values of IGBT gate - emitter resistances. Converter working OK and completely assembled. Q100 kV-power PCB 4512 108 0862x / 0934x

MINUS PLUS

G1

G2,3,4

E1

E2,3,4

Gx Ex

Ω

3.8kΩ ±10%

0Ω

PLUS MINUS

G1

G2,3,4

E1

E2,3,4

Gx Ex

4.2kΩ ±10%

• Record the conditions in the appendix.

Ω

0Ω

< 200mV

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4.2.3. Overvoltage diode check

cathode = heat sink plate

MINUS PLUS

cathode

V500

V501,2,3

anode

V500

V501,2,3

➙

310mV ±10%

PLUS MINUS

cathode

V500

V501,2,3

anode

V500

V501,2,3

➙

∞

cathode V5xx anode V5xx 0 cathode V5xx anode V5xx 0

• Record the conditions in the appendix.

4.2.4. Resistor check (PCB versions 4512 108 0862x / 0934x)

• Check 2 groups of 3 parallel resistors:

R506 / 507 / 508

and

R509 / 510 / 511

With 39Ω ±5% per group. Each resistor must have a resistance of 13Ω ±5%.

• Record the conditions in the appendix.

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4.2.5. Power cable harness check

• Check internal converter power cable connections at resonance capacitors C3:2 and C13:2. If the connectors look like (2) no additional action is necessary. If one of the connectors looks like (1) and if signs of overheating are visible replace the converter.

(1) (2)

• Record the conditions in the appendix.

4.2.6. Resonance capacitor check

• Remove primary lines from resonance capacitors C3:1 and C13:1 of frontal (and rear) converter.

• Check both capacitors for:

- short-circuit

- open connection

As it is not possible to measure the capacitance with an ohmmeter it is sufficient to see a variable resistance value for a certain time and finally a high resistance or open connection. Once a high resistance or open connection is displayed reverse the measuring lines. If it comes again to an unstable resistance display with a high resistance or open connection display at the end, the capacitor should be OK.

If a capacitance measuring device is available it should display 8µF ±5% (apart from the meter tolerance).

If a capacitor is defective (short or open) and no other part of the converter is defective which requires a converter unit exchange, replace the capacitor (2019 321 00016).

• Record the conditions in the appendix.

NOTE

Leave the primary lines disconnected from the capacitors for further tests.

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OPTIMUS CONVERTER TEST KIT

5. Check of the high voltage transformer

• Remove PCB EZ130 kV-control.

• Insert extender PCB at EZ130 X1 (or use the backpanel connections, which is less convenient).

• Establish oscilloscope connections:

channel 1 = anode EZ130 X1:C17 10 or 20mV/div channel 2 = cathode EZ130 X1:C16 10 or 20mV/div ground = EZ130 X1 :A17 :A16 trigger = positive slope anode ch1 or negative slope cathode ch2

trigger level according to signal level time base = 500ms/div or 1s/div

Signal amplitudes might look different depending on the battery type, connection cables used and the "contact force" at the battery.

• Measure

(1) with high voltage cables and tube connected.

(2) with high voltage cables only.

(3) without high voltage cables connected.

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5.1. Analysis

(1) and (2) have to look almost the same (symmetry and amplitude).

If (1) has a lower amplitude or a different kV behavior compared to (2) and (3) the tube might be defective.

(3) should have a steeper (faster) discharging ramp as the capacitance of the HV cable is missing

(tank only 3nF, 20m cable typically 1.5nF) assuming amplitude and symmetry are the same.

If (2) and (3) look different (amplitude and symmetry) and if (3) is symmetric the HV cable(s) might be defective.

If (3) shows an asymmetric amplitude the HV tank must be replaced.

• Check against the following chart:

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6. Visual check of the X-ray tube

• If possible remove the collimator and the X-ray tube window assembly. is there any visible damage?

A cracked tube or the loss of its vacuum could be a reason to destroy the converter.

• Record the conditions in the appendix.

7. Interim results

At this point

-

generator parts and units

-

tube(s)

-

HV cables

have been checked.

Something might have been exchanged or all tests came to an OK-result.

• Remove the extender PCB and reinsert kV-control EZ130.

WARNING!

All followings checks must be made

Check that the converter mains lines mains at ENK1 :1 :3 :5

• Switch ON all generator breakers and the mains supply.

with

mains power.

still

have no connection to

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8. Tube check with Rotor Control part 1

In case the tube was rotating during tripping of mains breakers the CPU remembers that the brake process has not been carried out (high speed rotor control only). About 40 seconds after switch-ON the tube brakes.

NOTE!

If the anode disk is not rotating before switch-ON it sounds like an acceleration process.

• Switch ON the generator and perform an audible check at the tube housing during the generator start-up (for further explanations see chapter 10.)

As the mains lines are not connected to the converters, error messages 02HI and 02HJ come up (converter DC is 0V, therefore out of range).

9. kV-driver test

• Perform the kV-driver test according to chapter 5.3 of the Converter R/F manual attached.

If the kV-driver test is successful prepare the generator for a next test:

• Lead the primary power cable(s) of QC13:1 (front and rear) through the current transformer(s) at each converter and reestablish the connection to the capacitor.

Optimus 65/80 with 2 converters:

Both current transformers must be inserted the same way. (Polarity, secondary transformer pins are marked with 1 and 2).

• Reestablish primary cable(s) at QC3:1 too.

• Reestablish all connections (mains cables of converter(s) at ENK1 :1 :3 :5.

WARNING!

Switch the generator OFF. Cut the generator completely from mains.

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10. Tube check with Rotor Control part 2

• Switch ON the generator. The system and the generator should be in ready condition.

Check of the tube vacuum:

• Push and hold PREP.

• Switch OFF the generator.

The anode is in free run now.

• Listen at the tube housing:

-

If the anode speed is down within 2 ... 3 minutes the tube is defective (no vacuum) and must be replaced.

-

If a decrease of anode speed is not audible within several minutes the vacuum is still OK.

• Switch the generator back ON.

-

A generator with high-speed rotor control brakes the tube automatically (chapter 8).

-

At generators with low -speed rotor control wait for ready condition, push PREP once and let go of the PREP switch to brake the tube.

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11. Tube and high-voltage cable test with high voltage

Even if

-

the battery test to check a short at the high voltage cables (chapter 5),

-

the visual tube check (chapter 6) and

-

the audible tube check (chapters 8 + 10)

did not lead to defective parts at first sight, these might be discovered once high voltage is up again.

Therefore the following test procedure was created to switch exposures just for 1ms before any part of the generator might be overloaded from a defective tube or HV cable.

• Switch the generator OFF.

• Establish the test cable with diode at the backpanel service measuring points:

EZX74 (CTRL_X_C/ = cathode of diode) > open plug

and

EZX77 (X_ACT_S/ = anode of diode) > green plug cover

• Establish just one side first (with the 4mm plug) of the test cable with resistor at the mAs short-circuit plug (either side, short-circuit plug remains in) of the measuring circuit EG100 (if access is not possible loosen screening cap of primary lines.)

• Establish oscilloscope connections:

channel 1 = anode EZ130 X4 AV_AN 20kV = 1V 0.5V/div

channel 2 = cathode (also positive) EZ130 X5 AV_CA 20kV = 1V 0.5V/div

ground = EZ130 X6/X32 GNDA

trigger = signal CTRL_X_C/ at EZX74 must be used , negative slope, trigger level 2.5V

(if a third probe is not available use one channel for triggering with CTRL_X_C/ and check anode and cathode side individually)

time base = 200µs/div, trigger delay -1div

Explanation: With these hardware modifications and exposure settings the exposure time is only 1ms.

The additional resistor simulates an emission current of 500mA which lets the mAs counter of mA-control terminate the exposure at 1ms (= 0.5mAs).

Under normal conditions the mAs counter is triggered by the signal X_ACT_S/. As this might be missing due to a problem in the system the additional diode drives, the kV start command CTRL_X_C/ also at X_ACT_S/ to trigger the mAs counter and ensures the short exposure. The oscilloscope must be triggered with CRTL_X_C/ for the same reason to get a display.

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