MEDTEQ High Frequency Insulation Tester

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The MEDTEQ High Frequency Insulation Tester (HFIT 7.0) is designed for broad testing of HF insulation against the following clauses of IEC 60601-2-2:2009:

  201.8.8.3.102 Active accessory HF leakage*
  201.8.8.3.103 Active accessory HF dielectric strength*
  201.15.101.4  NE cord insulation

*These clauses are also referenced from IEC 60601-2-18:2009

The equipment has evolved over several years  and now provides the following five types
of test waveforms: 

Mode Peak voltage (Vp) Crest factor Description 
Sine 1500 1.4 Essentially sinusoidal waveform, 310-450kHz
Modified Sine 2000 1.8 Sine wave with amplitude modulation to increase the crest factor
Burst 3500 2.0-6.0 Bursts of sine waves, adjustable duty cycle (12kHz pulse repetition rate)
Pulse Low 5000 4.0-6.5 Decaying sine wave, adjustable damping (12kHz pulse repetition rate)
Pulse High  7200 4.0-6.5 Decaying sinewave, adjustable damping (11.7kHz pulse repetition rate)

Crest factor ranges may depend on the load characteristics (capacitance and dissipation factor). The HFIT is designed to have overlapping ranges so that the required crest factor in IEC 60601-2-2 can be obtained assuming reasonable quality insulation materials..

To handle the very high VA loads associated with both high voltage and high frequency, a resonant circuit is used. This method allows peak of up to 10kVA, and continuous outputs of 300VA. Due to the use of a resonant circuit, the fundamental frequency varies with the capacitive load. The equipment is designed to have approximately 440kHz open circuit, reducing to aroun 315kHz at full load (100pF for the standard model). 

Many manufacturers rate insulation using "volts peak to peak" or "Vpp", which is approximately two times Vp ratings. The maximum output of the MEDTEQ HFIT is approximately 13kVpp.  

For test laboratories, the standard model (HFIT 7.0) has been designed to provide a variety of waveforms to ensure that the requirements in IEC 60601-2-2 can be tested from the leakage current test (400Vp, crest factor 1.4) to insulated rated at up to 6000Vp (test volatge 7200V, crest factor 6.0).

Limited option models are also availble for manufacturers that may have a certain range of test requirements (e.g. endoscopic insulation). The load range (capacitance in pF) varies as a function of the peak output voltage required. Frequency stabilized versions are also available depending on the peak voltage and load requirements. 

The HFIT includes a internal 1000:1 divider which is adjusted to be within 0.5% in the range of 300-500kHz using two independent methods . The equipment also includes a 1Ω high frequency shunt to allow current monitoring and leakage current testing. The user can monitor the applied voltage and load current using an oscilloscope.  

The standard model is designed to handle a 100pF test load (equivalent to 360VA: 1200Vrms, 400kHz, 100pF). Higher capacitive loads are possible depending on the required peak output. For reference, 30cm of 300Vac rated insulation is typically around 50pF. The latest version of equipment is provided with:

  • overload detection 
  • overvoltage detection (excessive rms output)
  • overtemperature detection 
  • zero start detecton 
  • 48Vdc external dc power supply

Users can select from the following range of models, or request a special version:

Model Peak output
(Vp)
Modes / details Load (pF)
7.0 7200 Sine, Modified Sine, Burst, Pulse Low, Pulse High 100
6.0 6000 Sine, Modified Sine, Burst, Pulse Low, Pulse High 150
4.5 4500 Sine, Modified Sine and/or Burst and/or Pulse (3 modes) 250
1S 1500 Sine only 2000
1F 1400 Sine only, frequency stabilized (high internal capacitance, frequency adjusted requested value ) 200
- - Discount if user provides own power supply (output range may depend on power supply ratings) -
- - Addition of PICO PC oscilloscope 4224 and short BNC cables 
(order may take an additional 1 week) 
-

Customized versions are also available (including pulse repetiton rates, modes).

For more details, refer to the HFIT Operation Manual. For quotes or additional information please contact MEDTEQ.