No announcement yet.

LW5 and 4 Construction forum

  • Filter
  • Time
  • Show
Clear All
new posts

  • #16
    Most electric prerotators that use a starter motor have a "soft start", a coil of resistance wire that limits the current to the motor during the initial few seconds of operation. Once the rotor has some rpms the resistance coil is shorted across by a second solenoid allowing full current to the motor.

    Pulsing the starter relay on and off isn't the way to go.

    You also want to eliminate the fuses as they are there to protect the wiring, but if you see the wiring burning just switch off the power.


    • #17

      Even in short circuit, your battery gives not much more than the current required by the stater. Thus, this wiring not need protected.
      If it is unable to support two times the normal without burning, then it is undersized
      Last edited by Jean - Claude; 07-10-2017, 09:02 AM.


      • #18
        Concerning the Belt PSRU, call me at 530 559 3897. Leave a message. Things are busy this week with all and EAA stuff.


        • #19
          Pre-Rotation Circuit Breaker problems.
          I have been reading up about this on the forum.
          I don't think I like the idea of watching for smoking wires, they are not separate from the rest of the wiring. My LI ion battery says it has 370 cold cranking amps.
          I just tried hand propping the rotor blades and pulsing the solenoid switch, I called it quits the second time I popped a 300A circuit breaker between the battery and the solenoid.
          My current circuit is, positive battery to 300A breaker to HD solenoid "0" gauge wire, then 7ft of 6 gauge wire to mast starter. Starter negative to battery negative, 6 gauge wire. Solenoid is on two cab panel mounted 12V switches in series.
          I see a soft start diagram on this Forum. It looks like that individual ran a completely separate medium voltage line from the starter into the cab through a switch and then a non breaker-ed line thru the firewall to the solenoid. Then across the solenoid terminals he has a resistor wire.
          I'm not an electrical guy, but ... If you only added a switch on the original hot lead to the starter and that switch was in the cab, then put a resistor wire across the main solenoid leads, You could switch the main hot lead in the cab and run the starter across the resistor wire on the solenoid, than switch on the solenoid and run higher amperage thru the solenoid straight from the battery???
          I really don't want to put a high amperage switch and reroute parts of the hot lead in the cab on its way to the starter.
          Is there another option?
          If not, OK. What type of wire, gauge, material, length and it will need to be insulated, it's in on the fire wall.
          Brad N954BH