9 replies to this topic

[HUBBA.HUBBA]

Using a T Handle Pull Cable as a emergency cut off. Anybody know how or what type of switch is used and how do you attach a pull cable to it.

[Timinichelsea]

Any battery cut off switch you buy will have a hole in the en dof teh 'key' you just have to install the switch in a convenient location, route the pull cable to it from wherever you want to have that located, also you'd probably need to make something to hold the cable near to the switch, cut to required length and use something like a cable nipple attachment to stop the cable coming through. You will also need to get as much oil into the pull cable as you can to stop the cable rusting to the lining.

Having one of these on a road car is a bit over the top.

[HUBBA.HUBBA]

Any battery cut off switch you buy will have a hole in the en dof teh 'key' you just have to install the switch in a convenient location, route the pull cable to it from wherever you want to have that located, also you'd probably need to make something to hold the cable near to the switch, cut to required length and use something like a cable nipple attachment to stop the cable coming through. You will also need to get as much oil into the pull cable as you can to stop the cable rusting to the lining.

Having one of these on a road car is a bit over the top.

[mini93]

You should use the correct cut off switch which has facility to cut power to ignition and not just the main battery feed because you will still run off the alternator. You will also need to fit the ceramic block as this is the part which soaks up the huge voltage surge if you were to cut off engine power at high revs, if it wasnt fitted you would damage the diodes inside the alternator etc

[steverose]

This is the type of thing that you will need Cut off switch im sure you can get them from other places but Merlin is normally cheaper. Then all you need is the pull cable for the outsdie, for mine I just fabricated a small L section to hold the pull cable a few inches before it goes into the master switch.

[mini93]

i got a link for you, cheaper

link 1 for switch

link 2 for 6ft pullcable

also a hint for you with the cable, use a small section of brake pipe as a guide for your cable that way you will be pulling at the switch in the correct direction, helps to turn the switch

[dklawson]

I don't understand what you are trying to achieve.

Are you using this on a street car and if so, where do you plan to mount the switch that it is not accessible to the driver?

If you are doing this on a race car, your sanctioning body will have rules on where the switch must be so corner workers can turn the car off. The links above are to the FIA switches. The FIA switches have two sets of contacts in addition to the battery power switch. One set of contacts is wired in series with the coil power (to kill the ignition) and the second is wired to the alternator and connects it to the "ceramic block". The block is a resistor that dumps the alternator output to earth to prevent a high voltage spike from burning up the alternator's electronics when the battery (load) suddenly disappears.

Some sanctioning bodies will allow two switches, one mounted on a wing for corner workers, the other dash mounted for the driver. If you choose the two switch option, the battery cable is routed through both switches in series. The coil power is also routed through both switches in series. However, the alternator kill circuit must be wired in parallel. Two wires leave the alternator output terminal, one wire going to each FIA switch. The other side of each switch has a dropping resistor connected to earth.

I think using a pull handle to remotely actuate an FIA switch is going to be a problem. In the off position the keys are practically ready to fall out of the switch. I expect that while you may be able to remotely turn the switch off, turning it on will be a two person job with one person pushing the key down into position while the other pushes the cable back in on the dash.

[mini93]

I think using a pull handle to remotely actuate an FIA switch is going to be a problem. In the off position the keys are practically ready to fall out of the switch. I expect that while you may be able to remotely turn the switch off, turning it on will be a two person job with one person pushing the key down into position while the other pushes the cable back in on the dash.

its really not a problem, all you do is push the cable in, the loose cable easy slides through the hole in the handle then you just flick the switch round. Its the same on most rally cars iv ever seen. the only time it will be remotly turned off is scruteneering and if theres a big accident, in which case i doubt he will be in a hurry and have time to get out, push in the cable then flick the switch back on

[charie t]

if it wasnt fitted you would damage the diodes inside the alternator etc

Think that would be the least of the worries if the battery cut off is needed

[mini93]

if it wasnt fitted you would damage the diodes inside the alternator etc

Think that would be the least of the worries if the battery cut off is needed

my cut off switch isnt far from my gear stick and have accidently caught it before, if i didnt have a resistor fitted it could have been a bit worse than my inconvenience (although i basicly bump started it whilst driving along)