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DC Motor TEST Box

Discussion in 'Sensors and Actuators' started by SCT27, Dec 5, 2017.

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  1. SCT27

    SCT27

    2
    0
    Dec 5, 2017
    Currently trying to make a test box with LED illumination for faster diagnosis.
    The voltages are DC which range from 0v to 115v DRIVING DC motors.

    I am using an LED driver:
    http://docs-europe.electrocomponents.com/webdocs/132e/0900766b8132e7d9.pdf

    Bridge Rectifier as the voltages change direction for the DC motor.

    Also using this LED:
    http://docs-europe.electrocomponents.com/webdocs/1395/0900766b813955e6.pdf

    Ive fitted a Heat Sink to the driver but still finding it cooking at 50v and above.

    Just ordered If anyone can suggest anything.......

    Many Thanks
     
  2. kellys_eye

    kellys_eye

    4,276
    1,146
    Jun 25, 2010
    How does the LED assist in your diagnosis? Does it just 'light up'?

    What form of heatsink did you fit? The tech sheet specifies an area of copper material (when pcb-mounted) such that the heat dissipation is via the limiter leads, not the case structure.
     
  3. SCT27

    SCT27

    2
    0
    Dec 5, 2017
    Yes basically the LED just needs to Light so that we Can see where getting Voltage at the motor. There is limited working time in the area where the motor is installed.

    Ive used the Heatsink below and this was attached to the casing:
    https://uk.rs-online.com/web/p/heatsinks/5040716/

    Not sure how it would be done via the limiter leads.?

    The LED is 30mA. So @115 DC would be 3.45W(looking at the driver spec its 3w) Still getting very hot
    at 60v
     
  4. kellys_eye

    kellys_eye

    4,276
    1,146
    Jun 25, 2010
    Fit a voltage limiting device across the LED arrangement (zener) to keep it within spec - say 30V.

    Page 3 of the datasheet notes that for dissipation of around 2000mW (2W) you need a copper dissipation plane on the leads that equals of exceeds 500mm^2 on a 1oz or 2oz copper plane. The maximum dissipation is stated at 3000mW (3W).

    AT 60V and 30mA you're at 1.8W and the heatsink requirement isn't being met.

    Even at 1W (30V @ 30mA) you need up to 100mm^2 of copper but that's only a 10mm square!
     
    SCT27 likes this.
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