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amps vs volts

Discussion in 'Truck & Equipment Repair' started by Snaaar, Dec 15, 2006.

  1. Snaaar

    Snaaar Member
    Messages: 76

    This is related to my thread in the Fisher forum.

    There is a power wire connected to the positive terminal of my battery. The wire runs into a fusible link, and there is a 30 amp fuse in there. My voltmeter tells me there is 12.30 volts coming into the fusible link, and 1.62 volts coming out (going towards a spreader control box). Does this sound right? Maybe I need basic electrical training, but I thought the fuse was there to protect components from a surge, not to reduce the voltage.:confused:
  2. Brian Young

    Brian Young PlowSite Veteran
    Messages: 3,394

    There should be 12+ volts coming out the "other"end too.
  3. Snaaar

    Snaaar Member
    Messages: 76

    OK, thanks. What I overlooked was that the power wire to the controller actually splits in two. After I detached the second connection, then I got the proper 12 volt reading on the other side of the fuse. This stuff really gets me flustered and makes me feel DUMB.
  4. clark lawn

    clark lawn PlowSite.com Addict
    from NE ohio
    Messages: 1,233

    there should be 12 volts coming out if the fuseable link if not there is probably corrosion in it giving it resistence.
  5. justme-

    justme- 2000 Club Member
    Messages: 2,138

    Just to clarify for future references:
    Fuses and fusable links are to protect against excessive and unsafe current draw- not necessarily surges. Actually, most fuses (which encompases all types includeing fusable links) will pass through a substantial surge without blowing, they are generally rated for sustained draw over a given length of time- 1 second, 1/4 second, etc. Fuses that need to protect sensative items like in test equipment have "quick blow" or "fast acting" fuses.

    Resistors resist the flow of electricity, normally reducing current, not voltage. Voltage drop across a portion of a circuit in automotive context usually signals a short circuit.

    Remember, Voltage is the pressure of a circuit, current is the rate of flow. (voltage is the pressure behind the water in the garden hose, current is how fast the water is flowing....)
  6. starc

    starc Senior Member
    Messages: 229

    More future reference:
    Watts = Amps x Volts
    Watts / Amps = Volts
    Watts / Volts = Amps
    Ohms = Volts / Amps