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Primary Current Draw — Parallax Forums

Primary Current Draw

LightfootLightfoot Posts: 228
edited 2007-03-27 03:02 in General Discussion
The current transformer I have in my HO train throttle power supply has a primary winding of 115 volts.

The secondary is 24 volts with a center tap and is rated at 10 amps.

How do I calculate the current draw on the primary for selecting a fuse?

Thanks

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Comments

  • Robert KubichekRobert Kubichek Posts: 343
    edited 2007-03-27 02:58
    10amps / (115/24) or 115/24=4.79 10/4.795=2.1

    24v 10 amps = 241 watts
    115v 2.1 amps = 241 watts

    I would go with a 2.5 or 3 amp fuse for primary.
    But if you want to protect the transformer,
    use a 2 amp fuse and don't draw the full load of 10 amps.

    Those transformers are kind of expensive aren't they???

    Bob
  • T ChapT Chap Posts: 4,241
    edited 2007-03-27 03:02
    Why not meter it?
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