A while back I was working on my controller for a big DC permanent magnet motor. That project has fizzled out for the time being, but one thing I was considering at the time was making an H-bridge out of automobile starter solenoids and providing PWM via a single array of high powered low side mosfets instead of 4 arrays. While working on a family member's car I encountered this drawing:
View attachment 64027
According to this (I don't know if it should be taken literally or not) the start signal engages only half of the solenoid coil, after which the solenoid closes and the remainder of the coil is powered through it's contact. This also should result in the solenoid latching closed IMO, which doesn't happen. So I'm a little confused about how the solenoid works, and if this drawing is flubbed or not.
1. If I wanted to use solenoids as I described above, is it possible to bring the negative side out the coil out so that it's not a chassis ground anymore?
2. If I wanted to use solenoids as I described above, when I apply voltage across it, will I be applying voltage across the entire coil or only half of it?
3. Is one side of the coil in fact internally connected to one side of the solenoid contact, and if so, why does it not latch?
4. How much current can a starter solenoid contact sustain for long periods of time? (keep in mind, it would not be switching heavy loads a whole lot, just remaining closed)
5. How much current does a starter solenoid draw?
View attachment 64027
According to this (I don't know if it should be taken literally or not) the start signal engages only half of the solenoid coil, after which the solenoid closes and the remainder of the coil is powered through it's contact. This also should result in the solenoid latching closed IMO, which doesn't happen. So I'm a little confused about how the solenoid works, and if this drawing is flubbed or not.
1. If I wanted to use solenoids as I described above, is it possible to bring the negative side out the coil out so that it's not a chassis ground anymore?
2. If I wanted to use solenoids as I described above, when I apply voltage across it, will I be applying voltage across the entire coil or only half of it?
3. Is one side of the coil in fact internally connected to one side of the solenoid contact, and if so, why does it not latch?
4. How much current can a starter solenoid contact sustain for long periods of time? (keep in mind, it would not be switching heavy loads a whole lot, just remaining closed)
5. How much current does a starter solenoid draw?