I had labored as vascular Help engineer to Help the cardio vascular imaging techniques within the area assigned to me. I had taken the accountability to handle the general service supply and make sure the buyer satisfaction to the optimum degree. I offered knowledgeable telephone and/or onsite technical Help to area service and prospects to attenuate gear downtime whereas bettering buyer satisfaction. I had taken further accountability to attach and configure all of the imaging techniques to the distant on-line centre by way of broad band and digital non-public community connectivity.
Since I used to be the technical Help for the area, I had the accountability to deal with the troublesome technical points which couldn’t be solved by the sector service engineers. I had taken initiative to carry out the facility and grounding audit for the southern area of India. I had been accountable to construct the technical Help workforce. i had reported on stable line to the regional service supervisor and dotted line to all India service supervisor. I had been assigned to deal with and resolve the frequent failure in cellular cardiac catheterization imaging system in one in every of our necessary finish consumer web site.
This method had a number of breakdown and picture high quality points. I needed to resolve the problem and convey again the client confidence degree in our gear high quality and repair supply. I had taken it as a problem and began the work on the web site. This Free CDR Template is dropped at your courtesy of gettingdownunder. com – Free Australian Immigration recommendation and sources for these seeking to make the transfer down underneath. Private Office Exercise: Prior to begin the service work , i had gone by way of the service log books and the error log information of the system to know the foundation explanation for the a number of and frequent failure of the system.
The info Assessment from the log e book and the service information, I discovered some severe energy high quality and grounding problem on the location. I had determined to conduct the preliminary energy and high quality audit within the web site. I inspected the facility distribution panel and located the facility cable measurement was underneath rated and unable to take the load. Throughout the imaging system utilization these energy feeding cables began heating up and resulted in cable insulation meltdown. So I advisable to alter the facility feeding cables with the proper measurement to face up to the load.
I measured the bottom impedance and located it extraordinarily excessive. So I inspected the earth pit and located the bonding between the earth wire and the earth rod open. upkeep division of the hospital knowledgeable and corrective motion had been taken instantly. As soon as the corrective motion was taken, I measured the bottom impedance once more and located throughout the advisable degree. I had booted up the imaging system and run the system diagnostic exams to isolate the issue. From the diagnostic take a look at outcomes, I suspected the issue within the Excessive voltage and the management electronics.
The excessive voltage circuit consists of inverter circuit, HV voltage tank with the filament transformer, HV cables for the anode and the cathode, and the x-ray tube. The block diagram as follows Since there was no x-ray output from the tube, I began the troubleshooting from the snubber board which feed the first facet of the HV tank. The snubber board accommodates 4 Insulated Gate Bipolar Transistors that switches the very massive currents utilized to the enter of the massive step – up transformer within the Excessive voltage tank.
This pcb is designed with very low DC resistance and inductance to attenuate the voltage drops at excessive currents. The resistorcapacitor-diode community on the board is used to damp the IGBT swap spikes. P. E. 2. eight As a result of absence of x-ray technology, the system displayed low MA and low KV error message on the console monitor. This is because of absence of output from the secondary facet of the HV tank. So I switched off the whole system and I checked the 400v, 70amps semiconductor fuse on the snubber board and located it faulty.
This fuse may be blown because of the fault present generated from the x-ray tube spit. The x-ray tube spit is generated within the glass tube insert of the x-ray because of the formation of metallization on the glass partitions. Then I checked This Free CDR Template is dropped at your courtesy of gettingdownunder. com – Free Australian Immigration recommendation and sources for these seeking to make the transfer down underneath. resistance between IGBT emitter terminal and the chassis floor with the true RMS multimeter and located quick. This indicated the harm of wire insulation within the IGBT.
I discovered each the IGBT module defective with the emitter to chassis floor quick. So I changed the IGBT module with the brand new one. After the alternative of IGBT module, I eliminated the anode and cathode HV cable on the tube facet and inspected the HV cable connector and located lot of carbon deposits because of the tube spit. The carbon deposit on the HV cable pins hamper the efficient conductivity, so I cleaned the connectors with Chemotronics Electro-wash resolution. I checked the HV receptacle properly on the xray tube and located it fully broken.
The insulation between the filament provide and grid was fully misplaced. So I discovered it not repairable and the whole x ray tube meeting wanted the alternative. I changed the x-ray tube meeting with the brand new one. Earlier than the facility on, I made a decision to double test the HV tank which is the primary a part of HV Circuit. The HV tank develops the extraordinarily excessive voltage essential to function the x-ray tube (as much as 125kv). The tank consists of resonant step up transformer, excessive voltage rectifiers, x-ray tube filament transformers, output ma and KV sensors and connectors.
I checked the rectifiers and the first and secondary windings of the transformer for any defect and located every thing okay. P. E. 2. 11 Then I made a decision to do the KV in Open Loop take a look at in HV tank. So I eliminated the HV cables on the HV tank output and stuffed the HV tank output receptacle with mineral oil. Later I switched on the system and run the KV open loop take a look at and it handed okay. Then I restored the HV cable connection between the tank and the x-ray tube in system off state. P. E. 2. 12 The x-ray tube and IGBT module alternative required the next calibration and changes for the conventional and secure perform of the system
IGBT Module Lifeless time wave type changes Filament Calibration KV and MA metering calibration Radiation dose calibration First I needed to regulate the lifeless time between the KV drives indicators on every of the IGBT pairs to proceed with the opposite calibration correctly. The improper lifeless time adjustment may result in harm of IGBT and the Generator driver board (which provides the set off pulse to the IGBT module). I linked the twin hint oscilloscope on the take a look at factors on the Generator driver board and noticed the waveform of each the IGBT drive sign.
I discovered the drive sign between the bottom and emitter of the IGBTs out of tolerance through the peak load. So this may result in cross-conduction within the IGBT module and the destruction of IGBT module. This Free CDR Template is dropped at your courtesy of gettingdownunder. com – Free Australian Immigration recommendation and sources for these seeking to make the transfer down underneath. The Generator driver PCB’s major job is to transform the KVP drive sign from the Excessive Voltage Provide regulator PCB to the degrees essential to drive the IGBTs on the SNUBBER PCB.
So I linked the oscilloscope within the excessive voltage regulator PCB take a look at factors and located the amplitude and frequency of the waveforms regular. So the foundation trigger was remoted and recognized with the Generator driver PCB. The issue was discovered on two of comparator’s output drives the gate transformers, which offer isolation from the excessive present circuitry and from excessive voltages current on every of the IGBT module. The faulty comparator IC chips have been eliminated and changed with the brand new one. After the alternative of the comparator IC chips the drive indicators have been discovered regular.
I had proceeded with the IGBT lifeless time adjustment with the scope meter linked with the generator driver PCB and set it throughout the safer restrict. I had checked the waveforms on the scope meter through the peak load situation and located okay. I carried out the filament calibration at totally different KV and Ma station and up to date the system filament drive database. This up to date database may be utilized by the filament driver PCB to drive the filament transformer to output right x-ray tube present in accordance the radiation approach.
After the filament calibration, I adjusted the KV and MA metering adjustment to sense and show the proper KV and MA worth of X-ray tube on the console through the time radiation publicity. Additionally I aligned the X-ray beam with the picture intensifier in numerous Subject of views. Subsequently I had run the collimator calibration for adjusting the collimator blades in numerous area of views. The digicam Iris opening is adjusted to set the radiation dose at a safer restrict advisable by the producer. The picture high quality was tuned to optimum degree. Abstract
I had checked and tuned the imaging system for the optimum picture high quality. I run totally different publicity methods with the Picture High quality Signature Take a look at Phantom and located the values throughout the specification. The client was delighted with the efficiency and the This Free CDR Template is dropped at your courtesy of gettingdownunder. com – Free Australian Immigration recommendation and sources for these seeking to make the transfer down underneath. picture high quality of the system after the completion of the service work. It was a problem for me to troubleshoot the system with a number of failures.
Throughout the course of hassle capturing I analyzed the circuits and remoted the issue areas with the Helpance of the data acquired from my area expertise and engineering course. I had learnt and utilized totally different troubleshooting methods to unravel this points. In nutshell I had thought-about this challenge as necessary milestone in my studying course of and in my profession development. This Free CDR Template is dropped at your courtesy of gettingdownunder. com – Free Australian Immigration recommendation and sources for these seeking to make the transfer down underneath.
