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Summary of Contents for MEDTEQ HFIT 8.0
- Page 1 MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net MEDTEQ High Frequency Insulation Tester HFIT 8.0 Operation Manual Issue 16 March 2018 Revision 16 March 2018 Page 1 of 40...
- Page 2 MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net {this page is intentionally blank} Revision 16 March 2018 Page 2 of 40...
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Page 3: Table Of Contents
MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net CONTENTS Overview ..............................5 Significant Risks ............................6 Getting started ............................7 Functional Description..........................8 Front panel controls, connections and display ..................8 Rear panel connections ......................... 9 Connection to external equipment and test load ................ - Page 4 MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net History of development ......................... 36 Calibration ............................. 37 11.1 Voltage ..............................37 11.2 Current monitor, BNC (1Ω shunt) ......................38 11.3 Current monitor (display) ........................38 11.4...
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Page 5: Overview
100pF capacitive load and up to 150pF in many conditions. The HFIT 8.0 achieves a new level in the series with in-built monitoring of Vp+, Vp-, Vrms, crest factor, Irms, Ipeak and frequency. Display of peak and rms utilize specially developed measurement systems designed to be intrinsically accurate at the frequency of interest, far exceeding the accuracy and reliability of existing measurement systems based on oscilloscopes and probes. -
Page 6: Significant Risks
MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net 2 Significant Risks As a result of risk assessment, the following significant risks/hazards were identified: Potential risk Information / Risk control Burns If the output is touched by the user when activated a burn hazard exists, similar to that provided by electrosurgical equipment. -
Page 7: Getting Started
MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net 3 Getting started This operation manual contains a significant amount of information. It is understood that users may wish to experiment with the controls prior to reading all the detail. In general the equipment is fairly robust and not easily damaged. -
Page 8: Functional Description
MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net 4 Functional Description 4.1 Front panel controls, connections and display Part Function HF HV output Output terminal with up to 7200Vp / 1200Vrms Return terminal Provides the return path and used to measure leakage current flowing through the test sample. -
Page 9: Rear Panel Connections
MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net 4.2 Rear panel connections Part Function Voltage monitor BNC type connection for output to an oscilloscope. output Output provides 1V/1000V of load voltage (1000:1 divider). -
Page 10: Connection To External Equipment And Test Load
Environment ground (earth) Notes on the set up: For the HFIT 8.0, an oscilloscope is optional (tests can be performed stand alone). The common laboratory practice of disconnecting the oscilloscope earth should be avoided, as this creates high noise and affects any peak measurement on the oscilloscope... -
Page 11: Display
MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net 4.4 Display Figure 4-1: Typical display The display includes the following items: Positive peak of the waveform, measured with range up to 8000Vp Negative peak of the waveform, measured with range up to -8000Vp... -
Page 12: Modes Of Operation
MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net 4.5 Modes of operation 4.5.1 Off Off Mode provides a secure way to ensure the output off. The output is inhibited by two different methods and the voltage control is not effective. -
Page 13: Modified Sine
MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net 4.5.3 Modified Sine Modified sine is similar to Sine mode except that it includes a small amount of 12kHz amplitude modulation in order to achieve a slightly higher crest factor around 1.6-1.9 depending on the test... -
Page 14: Burst
MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net 4.5.4 Burst Burst mode consists of bursts of sine waves at a 12kHz pulse repetition rate. At the end of the burst, the main pulses are turned off and the output is “damped” by switching in a resistor to quickly discharge the energy in the resonant circuit. -
Page 15: Pulse
MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net 4.5.5 Pulse In Pulse mode, a high pulse is output which is then allowed to decay at the natural frequency of the circuit. As with Burst, the crest factor can be adjusted by varying the timing in which a damping resistor is switched in to remove energy from the resonant circuit. -
Page 16: Auto Mode
MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net 4.5.6 Auto Mode In Auto mode, the user sets the target peak value (VpSet) and presses the start button for 2s to start the test. -
Page 17: Warning Messages
MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net 4.6 Warning messages The following table shows the warning messages, meaning, system response and user action. All warnings are accompanied by a triple beep (may be repeated every 3s depending on warning). -
Page 18: Principle Of Operation
MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net 5 Principle of operation 5.1 Basic pulse The main output is created using a switched resonant circuit: Step up transformer Power supply MOSFET Figure 5-1: Simplified circuit of the HFIT 7.0 The MOSFET switch is pulsed (turned on) for less than 1µs during which energy is stored in both the... - Page 19 MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net If new MOSFET pulses are provided regularly, the result is a pulsed decaying waveform as follows: Figure 5-3: Repeated pulses of decaying sine waves (pulse repetition rate 10kHz)
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Page 20: Pulse, Crest Factor Modification
MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net 5.2 Pulse, crest factor modification The crest factor of the pulse waveform can be increased by switching in a “damping” resistor (after the peak) to absorb the energy of the pulse. -
Page 21: Modified Sine, Burst Modes
MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net 5.4 Modified sine, Burst modes As described in Section 4.5.3 Modified Sine is a amplitude modified sine wave. It is created by temporarily turning off the top up pulses and allowing the waveform to decay naturally for a short period at the 12kHz repetition rate. -
Page 22: Operation
MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net 6 Operation 6.1 HF Dielectric strength testing Always use the standard (e.g. IEC 60601-2-2) as the primary reference. The dielectric strength test should be performed according to the following procedure: Pre-condition the sample as required in the standard (e.g. -
Page 23: Mode Selection, Load Limit (Based On Rated Voltage)
NG2 = for a 150pF load, the usable range is limited to 6000Vp The HFIT 8.0 displays the target crest factor based on the current peak (for Sine ~ Pulse modes) or target peak (for Auto mode). Since the test voltage is 20% of rated voltage, the effective formula used is: = (Vp/1.2-400)/600... -
Page 24: Hf Leakage Current Testing
400Vp (or as required for the test). In the 2017 edition of IEC 60601-2-2, the limit has been raised by a factor of approximately 2.2. The HFIT 8.0 has a resolution of 1mA for displayed values, and an accuracy of ±3%. Revision 16 March 2018... -
Page 25: Hf Insulation Breakdown - Theory And Detection
MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net 7 HF insulation breakdown – theory and detection 7.1 Thermal effects / dielectric dissipation factor (δ) All insulating materials heat up when an ac voltage is applied. -
Page 26: Dielectric Breakdown
Also, it is possible to perform experiments on the temperature of the insulation. A method used by MEDTEQ is to wrap the insulation in thin copper foil (0.05mm) with a thermocouple inserted. Apply the HIT HF HV terminal to the internal conductor, and the HFIT Return terminal to the copper foil (to avoid damage of the temperature monitor/logger). -
Page 27: Limitations In Iec 60601-2-2
MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net additional 1000V causes no breakdown. Theoretical simulations indicate that the thinner the insulation, the lower the voltage at which corona occurs. Since the damage mechanism is surface damage, thinner insulation is also more likely to be permanently damaged from corona. -
Page 28: Hfit Measurement Methods, Error Analysis And Validation
As such, a detailed description, error analysis and validation are provided to give users confidence in the measurement methods used in the HFIT. These methods have been specially designed by MEDTEQ to be intrinsically or inherently accurate in the range of interest. Most accurate measurement systems are designed approximately and then adjusted against a higher accuracy reference system. -
Page 29: Voltage Divider
MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net 8.2 Voltage divider The system includes a 1000:1 capacitive voltage divider which uses a series of 150pF mica capacitors (15 in total, resulting in a 10pF load to the high voltage output). -
Page 30: Error Analysis
MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net Any trigger indicates the DAC is below the peak of the output waveform (i.e. the peak is >4000Vp), while no trigger indicates the peak must be <4000Vp. The software uses this indication together with successive approximation method to find the precise value of the actual peak. -
Page 31: Validation (Oscilloscope Method)
MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net 8.3.3 Validation (Oscilloscope method) The peak detection system was validated by an external 12 bit oscilloscope and active high voltage probe: Prior to the test, the following steps were taken to ensure the accuracy of the reference system: A suitable range was selected for the particular test (e.g. -
Page 32: Vrms Measurement
MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net 8.4 Vrms measurement 8.4.1 Available methods For rms/dc conversion, there are four well established methods: Thermal/transfer – uses the property that the heat produced in a wide band resistor will be •... -
Page 33: Hfit Implementation
It is the opinion of MEDTEQ that these small transients are not relevant to the test target (thermal burns from HF leakage current) and are difficult to measure accurately. -
Page 34: Crest Factor
100mVrms (at the divider, shunt BNC output) 1200Vrms, peak voltages from 400Vp to 7200Vp in the frequency range of 300-500kHz. These devices have been validated in MEDTEQ Reports 58050 and 58051 which are available on request. From February 2018, shipped products will include a formal calibration report and a traceability chart which provides an overview of how traceability at high frequency is achieved. -
Page 35: Measurements By Oscilloscope/Probe
MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net 9 Measurements by oscilloscope/probe Although it is common to use oscilloscopes (scopes) and high voltage probes for measurements at high voltage and high frequency, in actual case they are designed to prioritize bandwidth over absolute accuracy. -
Page 36: History Of Development
As the load under test is part of the resonant circuit, the test frequency depends on the test sample. A test sample will typically have around 10-70pF capacitance. The MEDTEQ HFIT is designed to stay within the range required by the standard (300-500kHz) with loads of up to 100pF up to 7.2kVp and up to 150pF for 6000Vp. -
Page 37: Calibration
MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net 11 Calibration 11.1 Voltage As discussed in previous sections calibration of high voltage at high frequency is difficult. Users should be aware that it is unlikely for ISO 17025 accredited calibration laboratories to offer traceable calibration at 300-500kHz for a 7.5kV 1000:1 divider for both peak and rms measurements. -
Page 38: Current Monitor, Bnc (1Ω Shunt)
MEDTEQ 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan Medical Device Test Equipment Ph (+81) 090-9897-2340 Education Qualification www.medteq.net 11.2 Current monitor, BNC (1Ω shunt) The resistance of the current monitor shunt can be confirmed using a 4 wire resistance method or equivalent (e.g. passing a known current and measuring the voltage drop), as per the following... -
Page 39: Other Displayed Values
It is the opinion of MEDTEQ that such transients should not be considered based on the principles of the leakage current tests (rms effect). -
Page 40: Specifications
Overvoltage (Vrms, Vpeak) Over temperature Power supply 48Vdc 160W (approximately 3.3Amax) Dedicated power supply 100-240Vac, worldwide approvals. 13 Contact details MEDTEQ can be contacted by the following means: Email: equipment@medteq.info peter.selvey@medteq.jp Post: 545-56 Tsujikuru-cho, Ise-shi, Mie, Japan 516-0046 Phone: +81 90 9897 2340...
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