Why do bikes have a solenoid?
I understand that it is a switch to connect the battery to the sarter. But why not just make the ignition switch the actual switch?
Is it because the amps are high so the switch would be too big to comfortably use? Because if that is the case, wouldn't a simple mechanical solution be better?
11 replies
Oooh you are talking about motorbikes. In my mind a bike is the manual peddle bicycle kind and I was wondering what kind of bicycle has a solenoid.
yeah it's kind of funny how the world can't decide if they are called motorcycles or motorbikes or bikes
Because a starter motor draws a hundred amps or so. The solenoid ensures that closing the circuit is done as quickly as possible to limit sparking - and also keep the sparking as far from the driver's fingers as possible. Also, it's closer to the starter motor and the battery, so the cables are short and don't waste as much power as if they had to snake through the firewall - not to mention the PITA of routing monter copper cables through the firewall.
Thanks!
Yes. I don't know about for motorcycles, but in a car, it's like hundreds of amps. That's a lot of fucking amps.
Thanks!
If you've ever seen a spaceship show or movie (Star Trek or Star Wars) where control consoles explode, you understand why solenoids are used for high power controls.
I do now!
The well-known "hundreds of amperes" are exactly the strongest current that the battery is able to give, and that's what the engineer wanted.
The starter motor practically short circuits the battery in the first moment. The idea is to set the engine in motion as quick as possible.
With a set of drag wheels the bike could take off without you.
The other comments are correct. Also, a solenoid that switches another set of contacts is called a relay, or contactor.