The Forestry Forum

General Forestry => Sawmills and Milling => Topic started by: bedway on May 09, 2008, 12:56:07 PM

Title: 12 volt motor
Post by: bedway on May 09, 2008, 12:56:07 PM
 Ok guys and ladies, I just need some reassurance on an electrical issue. Im hooking up my 12 volt gearmotor for my power up and down on the sawhead. Im installing a fuse in the system. Should it go between the battery and switch, or between the gearmotor and switch? Also does it mater if its on the hot wire or ground?    thanks bedway
Title: Re: 12 volt motor
Post by: theorm on May 09, 2008, 01:35:41 PM
Bedway,

You definitely want to put the fuse on the hot side so pulling it will kill the whole circuit. The preferred place would be between the battery & the switch.

Electricity will go where ever it can, so if you kill the whole circuit you won't get any surprises when you think the circuit is disabled. If you fused the ground side, a short to ground would allow the motor to still operate when you think it is disabled. Be very careful.

Theo
ex-submarine electrician (BIG batteries)
Title: Re: 12 volt motor
Post by: solidwoods on May 09, 2008, 01:54:53 PM
He is using a dc motor with a reversing switch.
So which side would he fuse?

I think it goes before the reversing switch, + side.

Also what fuse to use?
jim
Title: Re: 12 volt motor
Post by: bedway on May 09, 2008, 02:13:07 PM
The motor pulls 3 amps according to the plate. I have a 5 amp fuse.
Title: Re: 12 volt motor
Post by: sparks on May 09, 2008, 02:16:01 PM
You will want to put a circuit breaker between your switch control and your 12 volt source. You cannot fuse the hot of the motor because you are using a reverse polarity to change motor direction. You will need to raise and lower your head and see what the amp draw on the motor is and then increase the curcuit breaker by 10 amps to cover the initial amp spike when you fisrt get the head moving.
Here is a sample diagram explaining what I mean.   Thanks all and be careful out there.