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DCR010505 Isolation Test

Rushil K K
Prodigy 650 points
Other Parts Discussed in Thread: DCR010505

A customer of mine needs to conduct EN61010-1 Safety tests for the DCR010505.
Please confirm whether the device will be able to withstand 1000Vrms for 1 minute duration for this test, like the datasheet says.

From datasheet:
 

Regards,
Rushil K K,
Analog Application Engineer 

  • 0
    TI__Mastermind 38230 points
    1. The isolated converter is a ground loop isolation regulator only. .
    2. The external continuous voltage difference limits are defined as voltages as measured between VIN (-) and Vout (-) ground). The converter is designed as ground fault isolation device. It is not designed to operate with a continuous voltage isolation barrier at greater than 60VDC. The isolation 1 second test validates only the magnetic coating separation between primary and secondary transformer wire. The purpose of the 1 second manufacturing isolation test detects typical barrier capacitance, CISO, of 24pf between transformer primary and secondary .When the barrier capacitance is greater than maximum limits, the converter is not released.
    3. The converter is not IEC 60950 rated. The UL requirement is a 1sec high voltage test immediately after manufacturing processing.
      1. Our 1 second 1kV test validates the transformer leakage. We temporarily short the primary pins, pins 1, 2&3 and secondary pins 12, 13, 14 for this 1 sec test. Any additional dielectric strength testing at 1 minute violates the SELV limits from the UL report UL1950.
      2. The 60 second orignal UL1950 recogition High voltagetest was  conducted only during the original approval UL testing . Note 2 in the product specifciation .
    4. The proposed HV  1 minute test can lead to immediate or long term degradation with possible failure of the isolation  barrier.

    Tom

     

  • 0 in reply to Tom Guerin
    TI__Prodigy 650 points

    Thank you Tom!

    I need your help to understand the significance of the 60 second test during UL approval. 
    I understand from your reply that the device would not be able to withstand 1kVrms for 60 seconds, and that in fact it can only take 60VDC for 60 seconds. What then is the use of the 60 second figure in the datasheet?
    Is it just to compare the level of isolation between different devices? 

    Regards,
    Rushil 

  • 0 in reply to Rushil K K
    TI__Mastermind 38230 points

    The 60 Second test was only required by UL one time only test during the initial UL1950 approval.The UL1950 safety report states the SELV rating as the converter does not have any creepage or clearance rating to operate at any other voltage rating limit.

    The 1 second HV isolation test is required by Ul on all isolated DCR-DCP converters.

    The electric strength for these converters is stated below.

    The external continuous voltage difference limits are defined as voltages as measured between VIN (-) and Vout (-) ground). The converter is designed as ground fault isolation device. It is not designed to operate with a continuous voltage isolation barrier at greater than 60VDC.

    The isolation 1 second production  test validates confirms magnetic coating separation and there is isolation  between primary and secondary transformer wires .

    The maximum potential difference ( Vin(+) to Vout ground ) as referenced to  a common ground is limited to continuous 60V DC or 42V Peak  AC transient between Vin(-) and Output ( ground) . . The primary and secondary transformer wires will  contact each other separated by magnet wire over-coating. The transformer wires are single coating material and not dual coated. The UL listing, E199929, voltage limits are SELV or 60VDC continuous or 42V transient peak.

    Tom

    Any further discussion can be completed off line at

    tguerin@ti.com